dump

This reverts commit 6a8394852e.

.github/workflows/server.yml

@@ -49,7 +49,7 @@ jobs:
           cache: maven
 
       - name: Test with Maven
-        run: cd dhfs-parent && mvn --batch-mode --update-snapshots package verify
+        run: cd dhfs-parent && mvn -T $(nproc) --batch-mode --update-snapshots package verify
 
       # - name: Build with Maven
       #   run: cd dhfs-parent && mvn --batch-mode --update-snapshots package # -Dquarkus.log.category.\"com.usatiuk.dhfs\".min-level=DEBUG

dhfs-parent/.run/Main 2.run.xml

@@ -0,0 +1,17 @@
+<component name="ProjectRunConfigurationManager">
+    <configuration default="false" name="Main 2" type="QsApplicationConfigurationType" factoryName="QuarkusApplication">
+        <option name="MAIN_CLASS_NAME" value="com.usatiuk.dhfs.Main"/>
+        <module name="server"/>
+        <option name="VM_PARAMETERS"
+                value="-XX:+UnlockDiagnosticVMOptions -XX:+DebugNonSafepoints --add-exports java.base/sun.nio.ch=ALL-UNNAMED --add-opens=java.base/java.nio=ALL-UNNAMED --add-exports java.base/jdk.internal.access=ALL-UNNAMED -ea -Dcom.usatiuk.dhfs.supportlib.native-path=$ProjectFileDir$/target/classes/native -Xmx2G -Ddhfs.webui.root=$ProjectFileDir$/../webui/dist -Ddhfs.fuse.root=${HOME}/dhfs_test/2/fuse -Ddhfs.objects.persistence.files.root=${HOME}/dhfs_test/2/data -Ddhfs.objects.persistence.stuff.root=${HOME}/dhfs_test/2/data/stuff -Ddhfs.objects.peerdiscovery.broadcast=false -Dquarkus.http.port=9020 -Dquarkus.http.ssl-port=9021 -Ddhfs.peerdiscovery.preset-uuid=22000000-0000-0000-0000-000000000000 -Ddhfs.peerdiscovery.static-peers=11000000-0000-0000-0000-000000000000:127.0.0.1:9010:9011"/>
+        <extension name="coverage">
+            <pattern>
+                <option name="PATTERN" value="com.usatiuk.dhfs.*"/>
+                <option name="ENABLED" value="true"/>
+            </pattern>
+        </extension>
+        <method v="2">
+            <option name="Make" enabled="true"/>
+        </method>
+    </configuration>
+</component>

dhfs-parent/.run/Main.run.xml

@@ -0,0 +1,18 @@
+<component name="ProjectRunConfigurationManager">
+    <configuration default="false" name="Main" type="QsApplicationConfigurationType" factoryName="QuarkusApplication"
+                   nameIsGenerated="true">
+        <option name="MAIN_CLASS_NAME" value="com.usatiuk.dhfs.Main"/>
+        <module name="server"/>
+        <option name="VM_PARAMETERS"
+                value="-XX:+UnlockDiagnosticVMOptions -XX:+DebugNonSafepoints --add-exports java.base/sun.nio.ch=ALL-UNNAMED --add-opens=java.base/java.nio=ALL-UNNAMED --add-exports java.base/jdk.internal.access=ALL-UNNAMED -ea -Dcom.usatiuk.dhfs.supportlib.native-path=$ProjectFileDir$/target/classes/native -Xmx2G -Ddhfs.webui.root=$ProjectFileDir$/../webui/dist -Ddhfs.fuse.root=${HOME}/dhfs_test/1/fuse -Ddhfs.objects.persistence.files.root=${HOME}/dhfs_test/1/data -Ddhfs.objects.persistence.stuff.root=${HOME}/dhfs_test/1/data/stuff -Ddhfs.objects.peerdiscovery.broadcast=false -Dquarkus.http.port=9010 -Dquarkus.http.ssl-port=9011 -Ddhfs.peerdiscovery.preset-uuid=11000000-0000-0000-0000-000000000000 -Ddhfs.peerdiscovery.static-peers=22000000-0000-0000-0000-000000000000:127.0.0.1:9020:9021"/>
+        <extension name="coverage">
+            <pattern>
+                <option name="PATTERN" value="com.usatiuk.dhfs.*"/>
+                <option name="ENABLED" value="true"/>
+            </pattern>
+        </extension>
+        <method v="2">
+            <option name="Make" enabled="true"/>
+        </method>
+    </configuration>
+</component>

dhfs-parent/autoprotomap/deployment/src/main/java/com/usatiuk/autoprotomap/deployment/ProtoSerializerGenerator.java

@@ -6,8 +6,8 @@ import com.usatiuk.autoprotomap.runtime.ProtoSerializer;
 import io.quarkus.gizmo.*;
 import jakarta.inject.Inject;
 import org.apache.commons.lang3.tuple.Pair;
-import org.jboss.jandex.Type;
 import org.jboss.jandex.*;
+import org.jboss.jandex.Type;
 import org.objectweb.asm.Opcodes;
 
 import java.util.ArrayList;

dhfs-parent/autoprotomap/integration-tests/pom.xml

@@ -82,7 +82,7 @@
 
     <profiles>
         <profile>
-            <id>native-image</id>
+            <id>native</id>
             <activation>
                 <property>
                     <name>native</name>

dhfs-parent/autoprotomap/integration-tests/src/main/resources/application.properties

@@ -1 +0,0 @@
-quarkus.package.jar.decompiler.enabled=true

dhfs-parent/kleppmanntree/pom.xml

@@ -18,6 +18,11 @@
             <artifactId>junit-jupiter-engine</artifactId>
             <scope>test</scope>
         </dependency>
+        <dependency>
+            <groupId>org.junit.jupiter</groupId>
+            <artifactId>junit-jupiter</artifactId>
+            <scope>test</scope>
+        </dependency>
         <dependency>
             <groupId>org.apache.commons</groupId>
             <artifactId>commons-collections4</artifactId>
@@ -30,5 +35,9 @@
             <groupId>org.pcollections</groupId>
             <artifactId>pcollections</artifactId>
         </dependency>
+        <dependency>
+            <groupId>jakarta.annotation</groupId>
+            <artifactId>jakarta.annotation-api</artifactId>
+        </dependency>
     </dependencies>
 </project>

dhfs-parent/kleppmanntree/src/main/java/com/usatiuk/kleppmanntree/KleppmannTree.java

@@ -1,5 +1,7 @@
 package com.usatiuk.kleppmanntree;
 
+import jakarta.annotation.Nonnull;
+import jakarta.annotation.Nullable;
 import org.apache.commons.lang3.tuple.Pair;
 
 import java.util.*;
@@ -53,18 +55,20 @@ public class KleppmannTree<TimestampT extends Comparable<TimestampT>, PeerIdT ex
             var node = _storage.getById(effect.childId());
             var curParent = _storage.getById(effect.newParentId());
             {
-                var newCurParentChildren = curParent.children().minus(node.meta().getName());
+                var newCurParentChildren = curParent.children().minus(node.name());
                 curParent = curParent.withChildren(newCurParentChildren);
                 _storage.putNode(curParent);
             }
 
-            if (!node.meta().getClass().equals(effect.oldInfo().oldMeta().getClass()))
+            if (effect.oldInfo().oldMeta() != null
+                    && node.meta() != null
+                    && !node.meta().getClass().equals(effect.oldInfo().oldMeta().getClass()))
                 throw new IllegalArgumentException("Class mismatch for meta for node " + node.key());
 
             // Needs to be read after changing curParent, as it might be the same node
             var oldParent = _storage.getById(effect.oldInfo().oldParent());
             {
-                var newOldParentChildren = oldParent.children().plus(node.meta().getName(), node.key());
+                var newOldParentChildren = oldParent.children().plus(effect.oldName(), node.key());
                 oldParent = oldParent.withChildren(newOldParentChildren);
                 _storage.putNode(oldParent);
             }
@@ -77,7 +81,7 @@ public class KleppmannTree<TimestampT extends Comparable<TimestampT>, PeerIdT ex
             var node = _storage.getById(effect.childId());
             var curParent = _storage.getById(effect.newParentId());
             {
-                var newCurParentChildren = curParent.children().minus(node.meta().getName());
+                var newCurParentChildren = curParent.children().minus(node.name());
                 curParent = curParent.withChildren(newCurParentChildren);
                 _storage.putNode(curParent);
             }
@@ -90,6 +94,7 @@ public class KleppmannTree<TimestampT extends Comparable<TimestampT>, PeerIdT ex
     }
 
     private void undoOp(LogRecord<TimestampT, PeerIdT, MetaT, NodeIdT> op) {
+        LOGGER.finer(() -> "Will undo op: " + op);
         if (op.effects() != null)
             for (var e : op.effects().reversed())
                 undoEffect(e);
@@ -140,8 +145,8 @@ public class KleppmannTree<TimestampT extends Comparable<TimestampT>, PeerIdT ex
                             }
                         }
                 }
-
             }
+
             if (!inTrash.isEmpty()) {
                 var trash = _storage.getById(_storage.getTrashId());
                 for (var n : inTrash) {
@@ -166,8 +171,8 @@ public class KleppmannTree<TimestampT extends Comparable<TimestampT>, PeerIdT ex
 
     public void move(NodeIdT newParent, MetaT newMeta, NodeIdT child, boolean failCreatingIfExists) {
         var createdMove = createMove(newParent, newMeta, child);
-        _opRecorder.recordOp(createdMove);
         applyOp(_peers.getSelfId(), createdMove, failCreatingIfExists);
+        _opRecorder.recordOp(createdMove);
     }
 
     public void applyExternalOp(PeerIdT from, OpMove<TimestampT, PeerIdT, MetaT, NodeIdT> op) {
@@ -178,7 +183,7 @@ public class KleppmannTree<TimestampT extends Comparable<TimestampT>, PeerIdT ex
     // Returns true if the timestamp is newer than what's seen, false otherwise
     private boolean updateTimestampImpl(PeerIdT from, TimestampT newTimestamp) {
         TimestampT oldRef = _storage.getPeerTimestampLog().getForPeer(from);
-        if (oldRef != null && oldRef.compareTo(newTimestamp) > 0) { // FIXME?
+        if (oldRef != null && oldRef.compareTo(newTimestamp) >= 0) { // FIXME?
             LOGGER.warning("Wrong op order: received older than known from " + from.toString());
             return false;
         }
@@ -186,20 +191,20 @@ public class KleppmannTree<TimestampT extends Comparable<TimestampT>, PeerIdT ex
         return true;
     }
 
-    public boolean updateExternalTimestamp(PeerIdT from, TimestampT timestamp) {
-        // TODO: Ideally no point in this separate locking?
+    public void updateExternalTimestamp(PeerIdT from, TimestampT timestamp) {
         var gotExt = _storage.getPeerTimestampLog().getForPeer(from);
         var gotSelf = _storage.getPeerTimestampLog().getForPeer(_peers.getSelfId());
-        if ((gotExt != null && gotExt.compareTo(timestamp) >= 0)
-                && (gotSelf != null && gotSelf.compareTo(_clock.peekTimestamp()) >= 0)) return false;
-        updateTimestampImpl(_peers.getSelfId(), _clock.peekTimestamp()); // FIXME:? Kind of a hack?
-        updateTimestampImpl(from, timestamp);
+        if (!(gotExt != null && gotExt.compareTo(timestamp) >= 0))
+            updateTimestampImpl(from, timestamp);
+        if (!(gotSelf != null && gotSelf.compareTo(_clock.peekTimestamp()) >= 0))
+            updateTimestampImpl(_peers.getSelfId(), _clock.peekTimestamp()); // FIXME:? Kind of a hack?
         tryTrimLog();
-        return true;
     }
 
     private void applyOp(PeerIdT from, OpMove<TimestampT, PeerIdT, MetaT, NodeIdT> op, boolean failCreatingIfExists) {
-        if (!updateTimestampImpl(from, op.timestamp().timestamp())) return;
+        if (!updateTimestampImpl(op.timestamp().nodeId(), op.timestamp().timestamp())) return;
+
+        LOGGER.finer(() -> "Will apply op: " + op + " from " + from);
 
         var log = _storage.getLog();
 
@@ -252,6 +257,7 @@ public class KleppmannTree<TimestampT extends Comparable<TimestampT>, PeerIdT ex
     }
 
     private LogRecord<TimestampT, PeerIdT, MetaT, NodeIdT> doOp(OpMove<TimestampT, PeerIdT, MetaT, NodeIdT> op, boolean failCreatingIfExists) {
+        LOGGER.finer(() -> "Doing op: " + op);
         LogRecord<TimestampT, PeerIdT, MetaT, NodeIdT> computed;
         try {
             computed = computeEffects(op, failCreatingIfExists);
@@ -291,6 +297,7 @@ public class KleppmannTree<TimestampT extends Comparable<TimestampT>, PeerIdT ex
 
     private void applyEffects(OpMove<TimestampT, PeerIdT, MetaT, NodeIdT> sourceOp, List<LogEffect<TimestampT, PeerIdT, MetaT, NodeIdT>> effects) {
         for (var effect : effects) {
+            LOGGER.finer(() -> "Applying effect: " + effect + " from op " + sourceOp);
             TreeNode<TimestampT, PeerIdT, MetaT, NodeIdT> oldParentNode = null;
             TreeNode<TimestampT, PeerIdT, MetaT, NodeIdT> newParentNode;
             TreeNode<TimestampT, PeerIdT, MetaT, NodeIdT> node;
@@ -304,7 +311,7 @@ public class KleppmannTree<TimestampT extends Comparable<TimestampT>, PeerIdT ex
                 node = _storage.getById(effect.childId());
             }
             if (oldParentNode != null) {
-                var newOldParentChildren = oldParentNode.children().minus(effect.oldInfo().oldMeta().getName());
+                var newOldParentChildren = oldParentNode.children().minus(effect.oldName());
                 oldParentNode = oldParentNode.withChildren(newOldParentChildren);
                 _storage.putNode(oldParentNode);
             }
@@ -313,12 +320,12 @@ public class KleppmannTree<TimestampT extends Comparable<TimestampT>, PeerIdT ex
             newParentNode = _storage.getById(effect.newParentId());
 
             {
-                var newNewParentChildren = newParentNode.children().plus(effect.newMeta().getName(), effect.childId());
+                var newNewParentChildren = newParentNode.children().plus(effect.newName(), effect.childId());
                 newParentNode = newParentNode.withChildren(newNewParentChildren);
                 _storage.putNode(newParentNode);
             }
             if (effect.newParentId().equals(_storage.getTrashId()) &&
-                    !Objects.equals(effect.newMeta().getName(), effect.childId().toString()))
+                    !Objects.equals(effect.newName(), effect.childId().toString()))
                 throw new IllegalArgumentException("Move to trash should have id of node as name");
             _storage.putNode(
                     node.withParent(effect.newParentId())
@@ -335,17 +342,32 @@ public class KleppmannTree<TimestampT extends Comparable<TimestampT>, PeerIdT ex
         NodeIdT newParentId = op.newParentId();
         TreeNode<TimestampT, PeerIdT, MetaT, NodeIdT> newParent = _storage.getById(newParentId);
 
+
         if (newParent == null) {
-            LOGGER.log(Level.SEVERE, "New parent not found " + op.newMeta().getName() + " " + op.childId());
-            return new LogRecord<>(op, null);
+            LOGGER.log(Level.SEVERE, "New parent not found " + op.newName() + " " + op.childId());
+
+            // Creation
+            if (oldParentId == null) {
+                LOGGER.severe(() -> "Creating both dummy parent and child node");
+                return new LogRecord<>(op, List.of(
+                        new LogEffect<>(null, op, _storage.getLostFoundId(), null, newParentId),
+                        new LogEffect<>(null, op, newParentId, op.newMeta(), op.childId())
+                ));
+            } else {
+                LOGGER.severe(() -> "Moving child node to dummy parent");
+                return new LogRecord<>(op, List.of(
+                        new LogEffect<>(null, op, _storage.getLostFoundId(), null, newParentId),
+                        new LogEffect<>(new LogEffectOld<>(node.lastEffectiveOp(), oldParentId, node.meta()), op, op.newParentId(), op.newMeta(), op.childId())
+                ));
+            }
         }
 
         if (oldParentId == null) {
-            var conflictNodeId = newParent.children().get(op.newMeta().getName());
+            var conflictNodeId = newParent.children().get(op.newName());
 
             if (conflictNodeId != null) {
                 if (failCreatingIfExists)
-                    throw new AlreadyExistsException("Already exists: " + op.newMeta().getName() + ": " + conflictNodeId);
+                    throw new AlreadyExistsException("Already exists: " + op.newName() + ": " + conflictNodeId);
 
                 var conflictNode = _storage.getById(conflictNodeId);
                 MetaT conflictNodeMeta = conflictNode.meta();
@@ -354,13 +376,16 @@ public class KleppmannTree<TimestampT extends Comparable<TimestampT>, PeerIdT ex
                     return new LogRecord<>(op, null);
                 }
 
-                String newConflictNodeName = conflictNodeMeta.getName() + ".conflict." + conflictNode.key();
-                String newOursName = op.newMeta().getName() + ".conflict." + op.childId();
+                LOGGER.finer(() -> "Node creation conflict: " + conflictNode);
+
+                String newConflictNodeName = op.newName() + ".conflict." + conflictNode.key();
+                String newOursName = op.newName() + ".conflict." + op.childId();
                 return new LogRecord<>(op, List.of(
                         new LogEffect<>(new LogEffectOld<>(conflictNode.lastEffectiveOp(), newParentId, conflictNodeMeta), conflictNode.lastEffectiveOp(), newParentId, (MetaT) conflictNodeMeta.withName(newConflictNodeName), conflictNodeId),
                         new LogEffect<>(null, op, op.newParentId(), (MetaT) op.newMeta().withName(newOursName), op.childId())
                 ));
             } else {
+                LOGGER.finer(() -> "Simple node creation");
                 return new LogRecord<>(op, List.of(
                         new LogEffect<>(null, op, newParentId, op.newMeta(), op.childId())
                 ));
@@ -372,11 +397,13 @@ public class KleppmannTree<TimestampT extends Comparable<TimestampT>, PeerIdT ex
         }
 
         MetaT oldMeta = node.meta();
-        if (!oldMeta.getClass().equals(op.newMeta().getClass())) {
+        if (oldMeta != null
+                && op.newMeta() != null
+                && !oldMeta.getClass().equals(op.newMeta().getClass())) {
             LOGGER.log(Level.SEVERE, "Class mismatch for meta for node " + node.key());
             return new LogRecord<>(op, null);
         }
-        var replaceNodeId = newParent.children().get(op.newMeta().getName());
+        var replaceNodeId = newParent.children().get(op.newName());
         if (replaceNodeId != null) {
             var replaceNode = _storage.getById(replaceNodeId);
             var replaceNodeMeta = replaceNode.meta();
@@ -385,11 +412,15 @@ public class KleppmannTree<TimestampT extends Comparable<TimestampT>, PeerIdT ex
                 return new LogRecord<>(op, null);
             }
 
+            LOGGER.finer(() -> "Node replacement: " + replaceNode);
+
             return new LogRecord<>(op, List.of(
                     new LogEffect<>(new LogEffectOld<>(replaceNode.lastEffectiveOp(), newParentId, replaceNodeMeta), replaceNode.lastEffectiveOp(), _storage.getTrashId(), (MetaT) replaceNodeMeta.withName(replaceNodeId.toString()), replaceNodeId),
                     new LogEffect<>(new LogEffectOld<>(node.lastEffectiveOp(), oldParentId, oldMeta), op, op.newParentId(), op.newMeta(), op.childId())
             ));
         }
+
+        LOGGER.finer(() -> "Simple node move");
         return new LogRecord<>(op, List.of(
                 new LogEffect<>(new LogEffectOld<>(node.lastEffectiveOp(), oldParentId, oldMeta), op, op.newParentId(), op.newMeta(), op.childId())
         ));
@@ -444,18 +475,18 @@ public class KleppmannTree<TimestampT extends Comparable<TimestampT>, PeerIdT ex
         walkTree(node -> {
             var op = node.lastEffectiveOp();
             if (node.lastEffectiveOp() == null) return;
-            LOGGER.info("visited bootstrap op for " + host + ": " + op.timestamp().toString() + " " + op.newMeta().getName() + " " + op.childId() + "->" + op.newParentId());
+            LOGGER.info("visited bootstrap op for " + host + ": " + op.timestamp().toString() + " " + op.newName() + " " + op.childId() + "->" + op.newParentId());
             result.put(node.lastEffectiveOp().timestamp(), node.lastEffectiveOp());
         });
 
         for (var le : _storage.getLog().getAll()) {
             var op = le.getValue().op();
-            LOGGER.info("bootstrap op from log for " + host + ": " + op.timestamp().toString() + " " + op.newMeta().getName() + " " + op.childId() + "->" + op.newParentId());
+            LOGGER.info("bootstrap op from log for " + host + ": " + op.timestamp().toString() + " " + op.newName() + " " + op.childId() + "->" + op.newParentId());
             result.put(le.getKey(), le.getValue().op());
         }
 
         for (var op : result.values()) {
-            LOGGER.info("Recording bootstrap op for " + host + ": " + op.timestamp().toString() + " " + op.newMeta().getName() + " " + op.childId() + "->" + op.newParentId());
+            LOGGER.info("Recording bootstrap op for " + host + ": " + op.timestamp().toString() + " " + op.newName() + " " + op.childId() + "->" + op.newParentId());
             _opRecorder.recordOpForPeer(host, op);
         }
     }

dhfs-parent/kleppmanntree/src/main/java/com/usatiuk/kleppmanntree/LogEffect.java

@@ -8,4 +8,17 @@ public record LogEffect<TimestampT extends Comparable<TimestampT>, PeerIdT exten
         NodeIdT newParentId,
         MetaT newMeta,
         NodeIdT childId) implements Serializable {
+    public String oldName() {
+        if (oldInfo.oldMeta() != null) {
+            return oldInfo.oldMeta().getName();
+        }
+        return childId.toString();
+    }
+
+    public String newName() {
+        if (newMeta != null) {
+            return newMeta.getName();
+        }
+        return childId.toString();
+    }
 }

dhfs-parent/kleppmanntree/src/main/java/com/usatiuk/kleppmanntree/OpMove.java

@@ -5,4 +5,9 @@ import java.io.Serializable;
 public record OpMove<TimestampT extends Comparable<TimestampT>, PeerIdT extends Comparable<PeerIdT>, MetaT extends NodeMeta, NodeIdT>
         (CombinedTimestamp<TimestampT, PeerIdT> timestamp, NodeIdT newParentId, MetaT newMeta,
          NodeIdT childId) implements Serializable {
+    public String newName() {
+        if (newMeta != null)
+            return newMeta.getName();
+        return childId.toString();
+    }
 }

dhfs-parent/kleppmanntree/src/main/java/com/usatiuk/kleppmanntree/StorageInterface.java

@@ -9,6 +9,8 @@ public interface StorageInterface<
 
     NodeIdT getTrashId();
 
+    NodeIdT getLostFoundId();
+
     NodeIdT getNewNodeId();
 
     TreeNode<TimestampT, PeerIdT, MetaT, NodeIdT> getById(NodeIdT id);

dhfs-parent/kleppmanntree/src/main/java/com/usatiuk/kleppmanntree/TreeNode.java

@@ -1,9 +1,9 @@
 package com.usatiuk.kleppmanntree;
 
+import jakarta.annotation.Nullable;
 import org.pcollections.PMap;
 
 import java.io.Serializable;
-import java.util.Map;
 
 public interface TreeNode<TimestampT extends Comparable<TimestampT>, PeerIdT extends Comparable<PeerIdT>, MetaT extends NodeMeta, NodeIdT> extends Serializable {
     NodeIdT key();
@@ -12,8 +12,15 @@ public interface TreeNode<TimestampT extends Comparable<TimestampT>, PeerIdT ext
 
     OpMove<TimestampT, PeerIdT, MetaT, NodeIdT> lastEffectiveOp();
 
+    @Nullable
     MetaT meta();
 
+    default String name() {
+        var meta = meta();
+        if (meta != null) return meta.getName();
+        return key().toString();
+    }
+
     PMap<String, NodeIdT> children();
 
     TreeNode<TimestampT, PeerIdT, MetaT, NodeIdT> withParent(NodeIdT parent);

dhfs-parent/kleppmanntree/src/test/java/com/usatiuk/kleppmanntree/KleppmanTreeSimpleTest.java

@@ -2,13 +2,15 @@ package com.usatiuk.kleppmanntree;
 
 import org.junit.jupiter.api.Assertions;
 import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.ValueSource;
 
 import java.util.List;
 
 public class KleppmanTreeSimpleTest {
     private final TestNode testNode1 = new TestNode(1);
     private final TestNode testNode2 = new TestNode(2);
-
+    private final TestNode testNode3 = new TestNode(3);
 
     @Test
     void circularTest() {
@@ -89,4 +91,75 @@ public class KleppmanTreeSimpleTest {
         Assertions.assertTrue(testNode2._storageInterface.getLog().size() <= 1);
     }
 
+    @ParameterizedTest
+    @ValueSource(booleans = {true, false})
+    void undoWithRenameTest(boolean opOrder) {
+        var d1id = testNode1._storageInterface.getNewNodeId();
+        var d2id = testNode2._storageInterface.getNewNodeId();
+        var d3id = testNode3._storageInterface.getNewNodeId();
+        testNode1._tree.move(testNode1._storageInterface.getRootId(), new TestNodeMetaDir("Test1"), d1id);
+        testNode2._tree.move(testNode1._storageInterface.getRootId(), new TestNodeMetaDir("Test1"), d2id);
+        testNode3._tree.move(testNode1._storageInterface.getRootId(), new TestNodeMetaDir("Test1"), d3id);
+        var r1 = testNode1.getRecorded();
+        var r2 = testNode2.getRecorded();
+        var r3 = testNode3.getRecorded();
+        Assertions.assertEquals(1, r1.size());
+        Assertions.assertEquals(1, r2.size());
+        Assertions.assertEquals(1, r3.size());
+
+        if (opOrder) {
+            testNode2._tree.applyExternalOp(3L, r3.getFirst());
+            testNode2._tree.applyExternalOp(1L, r1.getFirst());
+        } else {
+            testNode2._tree.applyExternalOp(1L, r1.getFirst());
+            testNode2._tree.applyExternalOp(3L, r3.getFirst());
+        }
+
+        Assertions.assertIterableEquals(List.of("Test1", "Test1.conflict." + d1id, "Test1.conflict." + d2id), testNode2._storageInterface.getById(testNode2._storageInterface.getRootId()).children().keySet());
+
+        if (opOrder) {
+            testNode1._tree.applyExternalOp(3L, r3.getFirst());
+            testNode1._tree.applyExternalOp(2L, r2.getFirst());
+        } else {
+            testNode1._tree.applyExternalOp(2L, r2.getFirst());
+            testNode1._tree.applyExternalOp(3L, r3.getFirst());
+        }
+
+        Assertions.assertIterableEquals(List.of("Test1", "Test1.conflict." + d1id, "Test1.conflict." + d2id), testNode1._storageInterface.getById(testNode1._storageInterface.getRootId()).children().keySet());
+
+        if (opOrder) {
+            testNode3._tree.applyExternalOp(2L, r2.getFirst());
+            testNode3._tree.applyExternalOp(1L, r1.getFirst());
+        } else {
+            testNode3._tree.applyExternalOp(1L, r1.getFirst());
+            testNode3._tree.applyExternalOp(2L, r2.getFirst());
+        }
+
+        Assertions.assertIterableEquals(List.of("Test1", "Test1.conflict." + d1id, "Test1.conflict." + d2id), testNode3._storageInterface.getById(testNode3._storageInterface.getRootId()).children().keySet());
+    }
+
+    @Test
+    void noFailedOpRecordTest() {
+        var d1id = testNode1._storageInterface.getNewNodeId();
+        var d2id = testNode1._storageInterface.getNewNodeId();
+        testNode1._tree.move(testNode1._storageInterface.getRootId(), new TestNodeMetaDir("Test1"), d1id);
+        Assertions.assertThrows(AlreadyExistsException.class, () -> testNode1._tree.move(testNode1._storageInterface.getRootId(), new TestNodeMetaDir("Test1"), d2id));
+        var r1 = testNode1.getRecorded();
+        Assertions.assertEquals(1, r1.size());
+    }
+
+    @Test
+    void externalOpWithDummy() {
+        Long d1id = testNode1._storageInterface.getNewNodeId();
+        Long f1id = testNode1._storageInterface.getNewNodeId();
+
+        testNode1._tree.applyExternalOp(2L, new OpMove<>(
+                new CombinedTimestamp<>(2L, 2L), d1id, new TestNodeMetaFile("Hi", 123), f1id
+        ));
+        testNode1._tree.applyExternalOp(2L, new OpMove<>(
+                new CombinedTimestamp<>(3L, 2L), testNode1._storageInterface.getRootId(), new TestNodeMetaDir("HiDir"), d1id
+        ));
+
+        Assertions.assertEquals(f1id, testNode1._tree.traverse(List.of("HiDir", "Hi")));
+    }
 }

dhfs-parent/kleppmanntree/src/test/java/com/usatiuk/kleppmanntree/TestStorageInterface.java

@@ -14,6 +14,7 @@ public class TestStorageInterface implements StorageInterface<Long, Long, TestNo
         _peerId = peerId;
         _nodes.put(getRootId(), new TestTreeNode(getRootId(), null, null));
         _nodes.put(getTrashId(), new TestTreeNode(getTrashId(), null, null));
+        _nodes.put(getLostFoundId(), new TestTreeNode(getLostFoundId(), null, null));
     }
 
     @Override
@@ -26,6 +27,11 @@ public class TestStorageInterface implements StorageInterface<Long, Long, TestNo
         return -1L;
     }
 
+    @Override
+    public Long getLostFoundId() {
+        return -2L;
+    }
+
     @Override
     public Long getNewNodeId() {
         return _curId++ | _peerId << 32;

dhfs-parent/objects/src/main/java/com/usatiuk/dhfs/objects/JDataVersionedWrapperLazy.java

@@ -1,44 +0,0 @@
-package com.usatiuk.dhfs.objects;
-
-import com.google.protobuf.ByteString;
-import com.usatiuk.dhfs.utils.SerializationHelper;
-
-public class JDataVersionedWrapperLazy implements JDataVersionedWrapper {
-    private final long _version;
-    private ByteString _rawData;
-    private JData _data;
-
-    public JDataVersionedWrapperLazy(long version, ByteString rawData) {
-        _version = version;
-        _rawData = rawData;
-    }
-
-    public JData data() {
-        if (_data != null)
-            return _data;
-
-        synchronized (this) {
-            if (_data != null)
-                return _data;
-
-            try (var is = _rawData.newInput()) {
-                _data = SerializationHelper.deserialize(is);
-            } catch (Exception e) {
-                throw new RuntimeException(e);
-            }
-            _rawData = null;
-            return _data;
-        }
-    }
-
-    public long version() {
-        return _version;
-    }
-
-    @Override
-    public int estimateSize() {
-        if (_data != null)
-            return _data.estimateSize();
-        return _rawData.size();
-    }
-}

dhfs-parent/objects/src/main/java/com/usatiuk/dhfs/objects/MergingKvIterator.java

@@ -1,192 +0,0 @@
-package com.usatiuk.dhfs.objects;
-
-import com.usatiuk.dhfs.objects.persistence.IteratorStart;
-import io.quarkus.logging.Log;
-import org.apache.commons.lang3.tuple.Pair;
-
-import java.util.*;
-import java.util.stream.Collectors;
-
-public class MergingKvIterator<K extends Comparable<K>, V> extends ReversibleKvIterator<K, V> {
-    private final Map<CloseableKvIterator<K, V>, Integer> _iterators;
-    private final NavigableMap<K, CloseableKvIterator<K, V>> _sortedIterators = new TreeMap<>();
-    private final String _name;
-
-    public MergingKvIterator(String name, IteratorStart startType, K startKey, List<IterProdFn<K, V>> iterators) {
-        _goingForward = true;
-        _name = name;
-
-        IteratorStart initialStartType = startType;
-        K initialStartKey = startKey;
-        boolean fail = false;
-        if (startType == IteratorStart.LT || startType == IteratorStart.LE) {
-            // Starting at a greatest key less than/less or equal than:
-            // We have a bunch of iterators that have given us theirs "greatest LT/LE key"
-            // now we need to pick the greatest of those to start with
-            // But if some of them don't have a lesser key, we need to pick the smallest of those
-            var initialIterators = iterators.stream().map(p -> p.get(initialStartType, initialStartKey)).toList();
-            try {
-                IteratorStart finalStartType = startType;
-                var found = initialIterators.stream()
-                        .filter(CloseableKvIterator::hasNext)
-                        .map((i) -> {
-                            var peeked = i.peekNextKey();
-//                            Log.warnv("peeked: {0}, from {1}", peeked, i.getClass());
-                            return peeked;
-                        }).distinct().collect(Collectors.partitioningBy(e -> finalStartType == IteratorStart.LE ? e.compareTo(initialStartKey) <= 0 : e.compareTo(initialStartKey) < 0));
-                K initialMaxValue;
-                if (!found.get(true).isEmpty())
-                    initialMaxValue = found.get(true).stream().max(Comparator.naturalOrder()).orElse(null);
-                else
-                    initialMaxValue = found.get(false).stream().min(Comparator.naturalOrder()).orElse(null);
-                if (initialMaxValue == null) {
-                    fail = true;
-                }
-                startKey = initialMaxValue;
-                startType = IteratorStart.GE;
-            } finally {
-                initialIterators.forEach(CloseableKvIterator::close);
-            }
-        }
-
-        if (fail) {
-            _iterators = Map.of();
-            return;
-        }
-
-        int counter = 0;
-        var iteratorsTmp = new HashMap<CloseableKvIterator<K, V>, Integer>();
-        for (var iteratorFn : iterators) {
-            var iterator = iteratorFn.get(startType, startKey);
-            iteratorsTmp.put(iterator, counter++);
-        }
-        _iterators = Map.copyOf(iteratorsTmp);
-
-        for (CloseableKvIterator<K, V> iterator : _iterators.keySet()) {
-            advanceIterator(iterator);
-        }
-
-        Log.tracev("{0} Created: {1}", _name, _sortedIterators);
-        switch (initialStartType) {
-//            case LT -> {
-//                assert _sortedIterators.isEmpty() || _sortedIterators.firstKey().compareTo(initialStartKey) < 0;
-//            }
-//            case LE -> {
-//                assert _sortedIterators.isEmpty() || _sortedIterators.firstKey().compareTo(initialStartKey) <= 0;
-//            }
-            case GT -> {
-                assert _sortedIterators.isEmpty() || _sortedIterators.firstKey().compareTo(initialStartKey) > 0;
-            }
-            case GE -> {
-                assert _sortedIterators.isEmpty() || _sortedIterators.firstKey().compareTo(initialStartKey) >= 0;
-            }
-        }
-    }
-
-    @SafeVarargs
-    public MergingKvIterator(String name, IteratorStart startType, K startKey, IterProdFn<K, V>... iterators) {
-        this(name, startType, startKey, List.of(iterators));
-    }
-
-
-    private void advanceIterator(CloseableKvIterator<K, V> iterator) {
-        if (!iterator.hasNext()) {
-            return;
-        }
-
-        K key = iterator.peekNextKey();
-        Log.tracev("{0} Advance peeked: {1}-{2}", _name, iterator, key);
-        if (!_sortedIterators.containsKey(key)) {
-            _sortedIterators.put(key, iterator);
-            return;
-        }
-
-        // Expects that reversed iterator returns itself when reversed again
-        var oursPrio = _iterators.get(_goingForward ? iterator : iterator.reversed());
-        var them = _sortedIterators.get(key);
-        var theirsPrio = _iterators.get(_goingForward ? them : them.reversed());
-        if (oursPrio < theirsPrio) {
-            _sortedIterators.put(key, iterator);
-            advanceIterator(them);
-        } else {
-            Log.tracev("{0} Skipped: {1}", _name, iterator.peekNextKey());
-            iterator.skip();
-            advanceIterator(iterator);
-        }
-    }
-
-    @Override
-    protected void reverse() {
-        var cur = _goingForward ? _sortedIterators.pollFirstEntry() : _sortedIterators.pollLastEntry();
-        Log.tracev("{0} Reversing from {1}", _name, cur);
-        _goingForward = !_goingForward;
-        _sortedIterators.clear();
-        for (CloseableKvIterator<K, V> iterator : _iterators.keySet()) {
-            // _goingForward inverted already
-            advanceIterator(!_goingForward ? iterator.reversed() : iterator);
-        }
-        if (_sortedIterators.isEmpty() || cur == null) {
-            return;
-        }
-        // Advance to the expected key, as we might have brought back some iterators
-        // that were at their ends
-        while (!_sortedIterators.isEmpty()
-                && ((_goingForward && peekImpl().compareTo(cur.getKey()) <= 0)
-                || (!_goingForward && peekImpl().compareTo(cur.getKey()) >= 0))) {
-            skipImpl();
-        }
-        Log.tracev("{0} Reversed to {1}", _name, _sortedIterators);
-    }
-
-    @Override
-    protected K peekImpl() {
-        if (_sortedIterators.isEmpty())
-            throw new NoSuchElementException();
-        return _goingForward ? _sortedIterators.firstKey() : _sortedIterators.lastKey();
-    }
-
-    @Override
-    protected void skipImpl() {
-        var cur = _goingForward ? _sortedIterators.pollFirstEntry() : _sortedIterators.pollLastEntry();
-        if (cur == null) {
-            throw new NoSuchElementException();
-        }
-        cur.getValue().skip();
-        advanceIterator(cur.getValue());
-        Log.tracev("{0} Skip: {1}, next: {2}", _name, cur, _sortedIterators);
-    }
-
-    @Override
-    protected boolean hasImpl() {
-        return !_sortedIterators.isEmpty();
-    }
-
-    @Override
-    protected Pair<K, V> nextImpl() {
-        var cur = _goingForward ? _sortedIterators.pollFirstEntry() : _sortedIterators.pollLastEntry();
-        if (cur == null) {
-            throw new NoSuchElementException();
-        }
-        var curVal = cur.getValue().next();
-        advanceIterator(cur.getValue());
-//        Log.tracev("{0} Read from {1}: {2}, next: {3}", _name, cur.getValue(), curVal, _sortedIterators.keySet());
-        return curVal;
-    }
-
-
-    @Override
-    public void close() {
-        for (CloseableKvIterator<K, V> iterator : _iterators.keySet()) {
-            iterator.close();
-        }
-    }
-
-    @Override
-    public String toString() {
-        return "MergingKvIterator{" +
-                "_name='" + _name + '\'' +
-                ", _sortedIterators=" + _sortedIterators.keySet() +
-                ", _iterators=" + _iterators +
-                '}';
-    }
-}

dhfs-parent/objects/src/main/java/com/usatiuk/dhfs/objects/persistence/CachingObjectPersistentStore.java

@@ -1,230 +0,0 @@
-package com.usatiuk.dhfs.objects.persistence;
-
-import com.usatiuk.dhfs.objects.*;
-import com.usatiuk.dhfs.utils.DataLocker;
-import io.quarkus.logging.Log;
-import io.quarkus.runtime.Startup;
-import jakarta.enterprise.context.ApplicationScoped;
-import jakarta.inject.Inject;
-import org.apache.commons.lang3.tuple.Pair;
-import org.eclipse.microprofile.config.inject.ConfigProperty;
-import org.pcollections.TreePMap;
-
-import javax.annotation.Nonnull;
-import java.util.LinkedHashMap;
-import java.util.Optional;
-import java.util.concurrent.ExecutorService;
-import java.util.concurrent.Executors;
-import java.util.concurrent.locks.ReentrantReadWriteLock;
-
-@ApplicationScoped
-public class CachingObjectPersistentStore {
-    private final LinkedHashMap<JObjectKey, CacheEntry> _cache = new LinkedHashMap<>();
-    private TreePMap<JObjectKey, CacheEntry> _sortedCache = TreePMap.empty();
-    private long _cacheVersion = 0;
-
-    private final ReentrantReadWriteLock _lock = new ReentrantReadWriteLock();
-    private final DataLocker _readerLocker = new DataLocker();
-
-    @Inject
-    SerializingObjectPersistentStore delegate;
-    @ConfigProperty(name = "dhfs.objects.lru.limit")
-    long sizeLimit;
-    @ConfigProperty(name = "dhfs.objects.lru.print-stats")
-    boolean printStats;
-
-    private long _curSize = 0;
-    private long _evict = 0;
-
-    private ExecutorService _statusExecutor = null;
-
-    @Startup
-    void init() {
-        if (printStats) {
-            _statusExecutor = Executors.newSingleThreadExecutor();
-            _statusExecutor.submit(() -> {
-                try {
-                    while (true) {
-                        Thread.sleep(10000);
-                        if (_curSize > 0)
-                            Log.info("Cache status: size=" + _curSize / 1024 / 1024 + "MB" + " evicted=" + _evict);
-                        _evict = 0;
-                    }
-                } catch (InterruptedException ignored) {
-                }
-            });
-        }
-    }
-
-    private void put(JObjectKey key, Optional<JDataVersionedWrapper> obj) {
-//        Log.tracev("Adding {0} to cache: {1}", key, obj);
-        _lock.writeLock().lock();
-        try {
-            int size = obj.map(JDataVersionedWrapper::estimateSize).orElse(16);
-
-            _curSize += size;
-            var entry = new CacheEntry(obj.<MaybeTombstone<JDataVersionedWrapper>>map(Data::new).orElse(new Tombstone<>()), size);
-            var old = _cache.putLast(key, entry);
-
-            _sortedCache = _sortedCache.plus(key, entry);
-            if (old != null)
-                _curSize -= old.size();
-
-            while (_curSize >= sizeLimit) {
-                var del = _cache.pollFirstEntry();
-                _sortedCache = _sortedCache.minus(del.getKey());
-                _curSize -= del.getValue().size();
-                _evict++;
-            }
-        } finally {
-            _lock.writeLock().unlock();
-        }
-    }
-
-    @Nonnull
-    public Optional<JDataVersionedWrapper> readObject(JObjectKey name) {
-        _lock.readLock().lock();
-        try {
-            var got = _cache.get(name);
-            if (got != null) {
-                return got.object().opt();
-            }
-        } finally {
-            _lock.readLock().unlock();
-        }
-        try (var lock = _readerLocker.lock(name)) {
-            // TODO: This is possibly racy
-//            var got = delegate.readObject(name);
-//            put(name, got);
-            return delegate.readObject(name);
-        }
-    }
-
-    public void commitTx(TxManifestObj<? extends JDataVersionedWrapper> names, long txId) {
-        var serialized = delegate.prepareManifest(names);
-        Log.tracev("Committing: {0} writes, {1} deletes", names.written().size(), names.deleted().size());
-        delegate.commitTx(serialized, txId, (commit) -> {
-            _lock.writeLock().lock();
-            try {
-                // Make the changes visible atomically both in cache and in the underlying store
-                for (var write : names.written()) {
-                    put(write.getLeft(), Optional.of(write.getRight()));
-                }
-                for (var del : names.deleted()) {
-                    put(del, Optional.empty());
-                }
-                ++_cacheVersion;
-                commit.run();
-            } finally {
-                _lock.writeLock().unlock();
-            }
-        });
-        Log.tracev("Committed: {0} writes, {1} deletes", names.written().size(), names.deleted().size());
-    }
-
-
-    private class CachingKvIterator implements CloseableKvIterator<JObjectKey, JDataVersionedWrapper> {
-        private final CloseableKvIterator<JObjectKey, JDataVersionedWrapper> _delegate;
-        // This should be created under lock
-        private final long _curCacheVersion = _cacheVersion;
-
-        private CachingKvIterator(CloseableKvIterator<JObjectKey, JDataVersionedWrapper> delegate) {
-            _delegate = delegate;
-        }
-
-        @Override
-        public JObjectKey peekNextKey() {
-            return _delegate.peekNextKey();
-        }
-
-        @Override
-        public void skip() {
-            _delegate.skip();
-        }
-
-        @Override
-        public void close() {
-            _delegate.close();
-        }
-
-        @Override
-        public boolean hasNext() {
-            return _delegate.hasNext();
-        }
-
-        @Override
-        public JObjectKey peekPrevKey() {
-            return _delegate.peekPrevKey();
-        }
-
-        private void maybeCache(Pair<JObjectKey, JDataVersionedWrapper> prev) {
-            _lock.writeLock().lock();
-            try {
-                if (_cacheVersion != _curCacheVersion) {
-                    Log.tracev("Not caching: {0}", prev);
-                } else {
-                    Log.tracev("Caching: {0}", prev);
-                    put(prev.getKey(), Optional.of(prev.getValue()));
-                }
-            } finally {
-                _lock.writeLock().unlock();
-            }
-        }
-
-        @Override
-        public Pair<JObjectKey, JDataVersionedWrapper> prev() {
-            var prev = _delegate.prev();
-            maybeCache(prev);
-            return prev;
-        }
-
-        @Override
-        public boolean hasPrev() {
-            return _delegate.hasPrev();
-        }
-
-        @Override
-        public void skipPrev() {
-            _delegate.skipPrev();
-        }
-
-        @Override
-        public Pair<JObjectKey, JDataVersionedWrapper> next() {
-            var next = _delegate.next();
-            maybeCache(next);
-            return next;
-        }
-    }
-
-    // Returns an iterator with a view of all commited objects
-    // Does not have to guarantee consistent view, snapshots are handled by upper layers
-    // Warning: it has a nasty side effect of global caching, so in this case don't even call next on it,
-    // if some objects are still in writeback
-    public CloseableKvIterator<JObjectKey, MaybeTombstone<JDataVersionedWrapper>> getIterator(IteratorStart start, JObjectKey key) {
-        _lock.readLock().lock();
-        try {
-            Log.tracev("Getting cache iterator: {0}, {1}", start, key);
-            var curSortedCache = _sortedCache;
-            return new MergingKvIterator<>("cache", start, key,
-                    (mS, mK)
-                            -> new MappingKvIterator<>(
-                            new NavigableMapKvIterator<>(curSortedCache, mS, mK),
-                            e -> {
-                                Log.tracev("Taken from cache: {0}", e);
-                                return e.object();
-                            }
-                    ),
-                    (mS, mK)
-                            -> new MappingKvIterator<>(new CachingKvIterator(delegate.getIterator(mS, mK)), Data::new));
-        } finally {
-            _lock.readLock().unlock();
-        }
-    }
-
-    private record CacheEntry(MaybeTombstone<JDataVersionedWrapper> object, long size) {
-    }
-
-    public long getLastTxId() {
-        return delegate.getLastCommitId();
-    }
-}

dhfs-parent/objects/src/main/java/com/usatiuk/dhfs/objects/persistence/SerializingObjectPersistentStore.java

@@ -1,56 +0,0 @@
-package com.usatiuk.dhfs.objects.persistence;
-
-import com.usatiuk.dhfs.objects.*;
-import jakarta.enterprise.context.ApplicationScoped;
-import jakarta.inject.Inject;
-import org.apache.commons.lang3.tuple.Pair;
-
-import javax.annotation.Nonnull;
-import java.util.Collection;
-import java.util.Optional;
-import java.util.function.Consumer;
-
-@ApplicationScoped
-public class SerializingObjectPersistentStore {
-    @Inject
-    ObjectSerializer<JDataVersionedWrapper> serializer;
-
-    @Inject
-    ObjectPersistentStore delegateStore;
-
-    @Nonnull
-    Collection<JObjectKey> findAllObjects() {
-        return delegateStore.findAllObjects();
-    }
-
-    @Nonnull
-    Optional<JDataVersionedWrapper> readObject(JObjectKey name) {
-        return delegateStore.readObject(name).map(serializer::deserialize);
-    }
-
-    // Returns an iterator with a view of all commited objects
-    // Does not have to guarantee consistent view, snapshots are handled by upper layers
-    public CloseableKvIterator<JObjectKey, JDataVersionedWrapper> getIterator(IteratorStart start, JObjectKey key) {
-        return new MappingKvIterator<>(delegateStore.getIterator(start, key), d -> serializer.deserialize(d));
-    }
-
-    public TxManifestRaw prepareManifest(TxManifestObj<? extends JDataVersionedWrapper> names) {
-        return new TxManifestRaw(
-                names.written().stream()
-                        .map(e -> Pair.of(e.getKey(), serializer.serialize(e.getValue())))
-                        .toList()
-                , names.deleted());
-    }
-
-//    void commitTx(TxManifestObj<? extends JDataVersionedWrapper> names, Consumer<Runnable> commitLocked) {
-//        delegateStore.commitTx(prepareManifest(names), commitLocked);
-//    }
-
-    void commitTx(TxManifestRaw names, long txId, Consumer<Runnable> commitLocked) {
-        delegateStore.commitTx(names, txId, commitLocked);
-    }
-
-    long getLastCommitId() {
-        return delegateStore.getLastCommitId();
-    }
-}

dhfs-parent/objects/src/main/java/com/usatiuk/dhfs/objects/snapshot/SnapshotManager.java

@@ -1,342 +0,0 @@
-package com.usatiuk.dhfs.objects.snapshot;
-
-import com.usatiuk.dhfs.objects.*;
-import com.usatiuk.dhfs.objects.persistence.IteratorStart;
-import com.usatiuk.dhfs.objects.transaction.TxRecord;
-import com.usatiuk.dhfs.utils.AutoCloseableNoThrow;
-import io.quarkus.logging.Log;
-import jakarta.enterprise.context.ApplicationScoped;
-import jakarta.inject.Inject;
-import org.apache.commons.lang3.mutable.MutableObject;
-import org.apache.commons.lang3.tuple.Pair;
-import org.eclipse.microprofile.config.inject.ConfigProperty;
-import org.pcollections.TreePMap;
-
-import javax.annotation.Nonnull;
-import java.lang.ref.Cleaner;
-import java.util.*;
-import java.util.concurrent.locks.ReentrantReadWriteLock;
-import java.util.function.Consumer;
-
-@ApplicationScoped
-public class SnapshotManager {
-    @Inject
-    WritebackObjectPersistentStore writebackStore;
-
-    private final ReentrantReadWriteLock _lock = new ReentrantReadWriteLock();
-
-    @ConfigProperty(name = "dhfs.objects.persistence.snapshot-extra-checks")
-    boolean extraChecks;
-
-    private long _lastSnapshotId = 0;
-    private long _lastAliveSnapshotId = -1;
-
-    private final Queue<Long> _snapshotIds = new ArrayDeque<>();
-    private TreePMap<SnapshotKey, SnapshotEntry> _objects = TreePMap.empty();
-    private final TreeMap<Long, ArrayDeque<SnapshotKey>> _snapshotBounds = new TreeMap<>();
-    private final HashMap<Long, Long> _snapshotRefCounts = new HashMap<>();
-
-    private void verify() {
-        assert _snapshotIds.isEmpty() == (_lastAliveSnapshotId == -1);
-        assert _snapshotIds.isEmpty() || _snapshotIds.peek() == _lastAliveSnapshotId;
-    }
-
-    // This should not be called for the same objects concurrently
-    public Consumer<Runnable> commitTx(Collection<TxRecord.TxObjectRecord<?>> writes) {
-//        _lock.writeLock().lock();
-//        try {
-//        if (!_snapshotIds.isEmpty()) {
-//        verify();
-        HashMap<SnapshotKey, SnapshotEntry> newEntries = new HashMap<>();
-        for (var action : writes) {
-            var current = writebackStore.readObjectVerbose(action.key());
-            // Add to snapshot the previous visible version of the replaced object
-            // I.e. should be visible to all transactions with id <= id
-            // and at least as its corresponding version
-            Pair<SnapshotKey, SnapshotEntry> newSnapshotEntry = switch (current) {
-                case WritebackObjectPersistentStore.VerboseReadResultPersisted(
-                        Optional<JDataVersionedWrapper> data
-                ) -> Pair.of(new SnapshotKey(action.key(), data.map(JDataVersionedWrapper::version).orElse(-1L)),
-                        data.<SnapshotEntry>map(o -> new SnapshotEntryObject(o, -1)).orElse(new SnapshotEntryDeleted(-1)));
-                case WritebackObjectPersistentStore.VerboseReadResultPending(
-                        PendingWriteEntry pending
-                ) -> {
-                    yield switch (pending) {
-                        case PendingWrite write ->
-                                Pair.of(new SnapshotKey(action.key(), write.bundleId()), new SnapshotEntryObject(write.data(), -1));
-                        case PendingDelete delete ->
-                                Pair.of(new SnapshotKey(action.key(), delete.bundleId()), new SnapshotEntryDeleted(-1));
-                        default -> throw new IllegalStateException("Unexpected value: " + pending);
-                    };
-                }
-                default -> throw new IllegalStateException("Unexpected value: " + current);
-            };
-
-
-            Log.tracev("Adding snapshot entry {0}", newSnapshotEntry);
-
-            newEntries.put(newSnapshotEntry.getLeft(), newSnapshotEntry.getRight());
-        }
-
-        _lock.writeLock().lock();
-        try {
-            return writebackStore.commitTx(writes, (id, commit) -> {
-                if (!_snapshotIds.isEmpty()) {
-                    assert id > _lastSnapshotId;
-                    for (var newSnapshotEntry : newEntries.entrySet()) {
-                        assert newSnapshotEntry.getKey().version() < id;
-                        var realNewSnapshotEntry = newSnapshotEntry.getValue().withWhenToRemove(id);
-                        if (realNewSnapshotEntry instanceof SnapshotEntryObject re) {
-                            assert re.data().version() <= newSnapshotEntry.getKey().version();
-                        }
-                        _objects = _objects.plus(newSnapshotEntry.getKey(), realNewSnapshotEntry);
-//                    assert val == null;
-                        _snapshotBounds.merge(newSnapshotEntry.getKey().version(), new ArrayDeque<>(List.of(newSnapshotEntry.getKey())),
-                                (a, b) -> {
-                                    a.addAll(b);
-                                    return a;
-                                });
-                    }
-                }
-                commit.run();
-            });
-        } finally {
-            _lock.writeLock().unlock();
-        }
-
-//        }
-
-//        verify();
-        // Commit under lock, iterators will see new version after the lock is released and writeback
-        // cache is updated
-        // TODO: Maybe writeback iterator being invalidated wouldn't be a problem?
-//        } finally {
-//            _lock.writeLock().unlock();
-//        }
-    }
-
-    private void unrefSnapshot(long id) {
-        Log.tracev("Unref snapshot {0}", id);
-        _lock.writeLock().lock();
-        try {
-            verify();
-            var refCount = _snapshotRefCounts.merge(id, -1L, (a, b) -> a + b == 0 ? null : a + b);
-            if (!(refCount == null && id == _lastAliveSnapshotId)) {
-                return;
-            }
-
-            long curCount;
-            long curId = id;
-            long nextId;
-            do {
-                Log.tracev("Removing snapshot {0}", curId);
-                _snapshotIds.poll();
-                nextId = _snapshotIds.isEmpty() ? -1 : _snapshotIds.peek();
-                while (nextId == curId) {
-                    _snapshotIds.poll();
-                    nextId = _snapshotIds.isEmpty() ? -1 : _snapshotIds.peek();
-                }
-
-                var keys = _snapshotBounds.headMap(curId, true);
-
-                long finalCurId = curId;
-                long finalNextId = nextId;
-                ArrayList<Pair<Long, SnapshotKey>> toReAdd = new ArrayList<>();
-                keys.values().stream().flatMap(Collection::stream).forEach(key -> {
-                    var entry = _objects.get(key);
-                    if (entry == null) {
-//                        Log.warnv("Entry not found for key {0}", key);
-                        return;
-                    }
-                    if (finalNextId == -1) {
-                        Log.tracev("Could not find place to place entry {0}, curId={1}, nextId={2}, whenToRemove={3}, snapshotIds={4}",
-                                entry, finalCurId, finalNextId, entry.whenToRemove(), _snapshotIds);
-                    } else if (finalNextId < entry.whenToRemove()) {
-                        _objects = _objects.plus(new SnapshotKey(key.key(), finalNextId), entry);
-                        assert finalNextId > finalCurId;
-                        toReAdd.add(Pair.of(finalNextId, new SnapshotKey(key.key(), finalNextId)));
-                    }
-                    _objects = _objects.minus(key);
-                });
-
-                toReAdd.forEach(p -> {
-                    _snapshotBounds.merge(p.getLeft(), new ArrayDeque<>(List.of(p.getRight())),
-                            (a, b) -> {
-                                a.addAll(b);
-                                return a;
-                            });
-                });
-
-                keys.clear();
-
-                if (_snapshotIds.isEmpty()) {
-                    _lastAliveSnapshotId = -1;
-                    break;
-                }
-
-                curId = _snapshotIds.peek();
-                _lastAliveSnapshotId = curId;
-
-                curCount = _snapshotRefCounts.getOrDefault(curId, 0L);
-            } while (curCount == 0);
-            verify();
-        } finally {
-            _lock.writeLock().unlock();
-        }
-    }
-
-    public static class IllegalSnapshotIdException extends IllegalArgumentException {
-        public IllegalSnapshotIdException(String message) {
-            super(message);
-        }
-
-        @Override
-        public synchronized Throwable fillInStackTrace() {
-            return this;
-        }
-    }
-
-    public class Snapshot implements AutoCloseableNoThrow {
-        private final long _id;
-        private static final Cleaner CLEANER = Cleaner.create();
-        private final MutableObject<Boolean> _closed = new MutableObject<>(false);
-
-        public long id() {
-            return _id;
-        }
-
-        private Snapshot(long id) {
-            _id = id;
-            _lock.writeLock().lock();
-            try {
-                verify();
-                if (_lastSnapshotId > id)
-                    throw new IllegalSnapshotIdException("Snapshot id " + id + " is less than last snapshot id " + _lastSnapshotId);
-                _lastSnapshotId = id;
-                if (_lastAliveSnapshotId == -1)
-                    _lastAliveSnapshotId = id;
-                if (_snapshotRefCounts.merge(id, 1L, Long::sum) == 1) {
-                    _snapshotIds.add(id);
-                }
-                verify();
-            } finally {
-                _lock.writeLock().unlock();
-            }
-            var closedRef = _closed;
-            var idRef = _id;
-            CLEANER.register(this, () -> {
-                if (!closedRef.getValue()) {
-                    Log.error("Snapshot " + idRef + " was not closed before GC");
-                }
-            });
-        }
-
-        public class CheckingSnapshotKvIterator implements CloseableKvIterator<JObjectKey, JDataVersionedWrapper> {
-            private final CloseableKvIterator<JObjectKey, JDataVersionedWrapper> _backing;
-
-            public CheckingSnapshotKvIterator(CloseableKvIterator<JObjectKey, JDataVersionedWrapper> backing) {
-                _backing = backing;
-            }
-
-            @Override
-            public JObjectKey peekNextKey() {
-                return _backing.peekNextKey();
-            }
-
-            @Override
-            public void skip() {
-                _backing.skip();
-            }
-
-            @Override
-            public JObjectKey peekPrevKey() {
-                return _backing.peekPrevKey();
-            }
-
-            @Override
-            public Pair<JObjectKey, JDataVersionedWrapper> prev() {
-                var ret = _backing.prev();
-                assert ret.getValue().version() <= _id;
-                return ret;
-            }
-
-            @Override
-            public boolean hasPrev() {
-                return _backing.hasPrev();
-            }
-
-            @Override
-            public void skipPrev() {
-                _backing.skipPrev();
-            }
-
-            @Override
-            public void close() {
-                _backing.close();
-            }
-
-            @Override
-            public boolean hasNext() {
-                return _backing.hasNext();
-            }
-
-            @Override
-            public Pair<JObjectKey, JDataVersionedWrapper> next() {
-                var ret = _backing.next();
-                assert ret.getValue().version() <= _id;
-                return ret;
-            }
-        }
-
-        public CloseableKvIterator<JObjectKey, JDataVersionedWrapper> getIterator(IteratorStart start, JObjectKey key) {
-            _lock.readLock().lock();
-            try {
-                Log.tracev("Getting snapshot {0} iterator for {1} {2}\n" +
-                        "objects in snapshots: {3}", _id, start, key, _objects);
-                return new CheckingSnapshotKvIterator(new TombstoneMergingKvIterator<>("snapshot", start, key,
-                        (tS, tK) -> new SnapshotKvIterator(_objects, _id, tS, tK),
-                        (tS, tK) -> new MappingKvIterator<>(
-                                writebackStore.getIterator(tS, tK), d -> d.version() <= _id ? new Data<>(d) : new Tombstone<>())
-                ));
-            } finally {
-                _lock.readLock().unlock();
-            }
-        }
-
-        @Nonnull
-        public Optional<JDataVersionedWrapper> readObject(JObjectKey name) {
-            try (var it = getIterator(IteratorStart.GE, name)) {
-                if (it.hasNext()) {
-                    if (!it.peekNextKey().equals(name)) {
-                        return Optional.empty();
-                    }
-                    return Optional.of(it.next().getValue());
-                }
-            }
-            return Optional.empty();
-        }
-
-        @Override
-        public void close() {
-            if (_closed.getValue()) {
-                return;
-            }
-            _closed.setValue(true);
-            unrefSnapshot(_id);
-        }
-    }
-
-    public Snapshot createSnapshot() {
-        _lock.writeLock().lock();
-        try {
-            return new Snapshot(writebackStore.getLastTxId());
-        } finally {
-            _lock.writeLock().unlock();
-        }
-    }
-
-    @Nonnull
-    public Optional<JDataVersionedWrapper> readObjectDirect(JObjectKey name) {
-        return writebackStore.readObject(name);
-    }
-}

dhfs-parent/objects/src/main/java/com/usatiuk/dhfs/objects/transaction/TransactionObject.java

@@ -1,10 +0,0 @@
-package com.usatiuk.dhfs.objects.transaction;
-
-import com.usatiuk.dhfs.objects.JData;
-import com.usatiuk.dhfs.objects.JDataVersionedWrapper;
-
-import java.util.Optional;
-
-public interface TransactionObject<T extends JData> {
-    Optional<JDataVersionedWrapper> data();
-}

dhfs-parent/objects/src/main/java/com/usatiuk/objects/JData.java

@@ -1,4 +1,4 @@
-package com.usatiuk.dhfs.objects;
+package com.usatiuk.objects;
 
 import java.io.Serializable;
 

dhfs-parent/objects/src/main/java/com/usatiuk/objects/JDataVersionedWrapper.java

@@ -1,4 +1,4 @@
-package com.usatiuk.dhfs.objects;
+package com.usatiuk.objects;
 
 public interface JDataVersionedWrapper {
     JData data();

dhfs-parent/objects/src/main/java/com/usatiuk/objects/JDataVersionedWrapperImpl.java

@@ -1,4 +1,4 @@
-package com.usatiuk.dhfs.objects;
+package com.usatiuk.objects;
 
 import jakarta.annotation.Nonnull;
 

dhfs-parent/objects/src/main/java/com/usatiuk/objects/JDataVersionedWrapperLazy.java

@@ -0,0 +1,39 @@
+package com.usatiuk.objects;
+
+import java.util.function.Supplier;
+
+public class JDataVersionedWrapperLazy implements JDataVersionedWrapper {
+    private final long _version;
+    private final int _estimatedSize;
+    private Supplier<JData> _producer;
+    private JData _data;
+
+    public JDataVersionedWrapperLazy(long version, int estimatedSize, Supplier<JData> producer) {
+        _version = version;
+        _estimatedSize = estimatedSize;
+        _producer = producer;
+    }
+
+    public JData data() {
+        if (_data != null)
+            return _data;
+
+        synchronized (this) {
+            if (_data != null)
+                return _data;
+
+            _data = _producer.get();
+            _producer = null;
+            return _data;
+        }
+    }
+
+    public long version() {
+        return _version;
+    }
+
+    @Override
+    public int estimateSize() {
+        return _estimatedSize;
+    }
+}

dhfs-parent/objects/src/main/java/com/usatiuk/objects/JDataVersionedWrapperSerializer.java

@@ -1,26 +1,29 @@
-package com.usatiuk.dhfs.objects;
+package com.usatiuk.objects;
 
 
 import com.google.protobuf.ByteString;
-import com.usatiuk.dhfs.utils.SerializationHelper;
 import jakarta.enterprise.context.ApplicationScoped;
+import jakarta.inject.Inject;
 
 import java.nio.ByteBuffer;
 
 @ApplicationScoped
-public class JavaDataSerializer implements ObjectSerializer<JDataVersionedWrapper> {
+public class JDataVersionedWrapperSerializer implements ObjectSerializer<JDataVersionedWrapper> {
+    @Inject
+    ObjectSerializer<JData> dataSerializer;
+
     @Override
     public ByteString serialize(JDataVersionedWrapper obj) {
         ByteBuffer buffer = ByteBuffer.allocate(Long.BYTES);
         buffer.putLong(obj.version());
         buffer.flip();
-        return ByteString.copyFrom(buffer).concat(SerializationHelper.serialize(obj.data()));
+        return ByteString.copyFrom(buffer).concat(dataSerializer.serialize(obj.data()));
     }
 
     @Override
     public JDataVersionedWrapper deserialize(ByteString data) {
         var version = data.substring(0, Long.BYTES).asReadOnlyByteBuffer().getLong();
         var rawData = data.substring(Long.BYTES);
-        return new JDataVersionedWrapperLazy(version, rawData);
+        return new JDataVersionedWrapperLazy(version, rawData.size(), () -> dataSerializer.deserialize(rawData));
     }
 }

dhfs-parent/objects/src/main/java/com/usatiuk/objects/JObjectKey.java

@@ -1,16 +1,33 @@
-package com.usatiuk.dhfs.objects;
+package com.usatiuk.objects;
 
 import com.usatiuk.dhfs.supportlib.UninitializedByteBuffer;
 
 import java.io.Serializable;
 import java.nio.ByteBuffer;
 import java.nio.charset.StandardCharsets;
+import java.util.UUID;
 
 public record JObjectKey(String name) implements Serializable, Comparable<JObjectKey> {
     public static JObjectKey of(String name) {
         return new JObjectKey(name);
     }
 
+    public static JObjectKey random() {
+        return new JObjectKey(UUID.randomUUID().toString());
+    }
+
+    public static JObjectKey first() {
+        return new JObjectKey("");
+    }
+
+    public static JObjectKey fromBytes(byte[] bytes) {
+        return new JObjectKey(new String(bytes, StandardCharsets.UTF_8));
+    }
+
+    public static JObjectKey fromByteBuffer(ByteBuffer buff) {
+        return new JObjectKey(StandardCharsets.UTF_8.decode(buff).toString());
+    }
+
     @Override
     public int compareTo(JObjectKey o) {
         return name.compareTo(o.name);
@@ -33,12 +50,4 @@ public record JObjectKey(String name) implements Serializable, Comparable<JObjec
         directBb.flip();
         return directBb;
     }
-
-    public static JObjectKey fromBytes(byte[] bytes) {
-        return new JObjectKey(new String(bytes, StandardCharsets.UTF_8));
-    }
-
-    public static JObjectKey fromByteBuffer(ByteBuffer buff) {
-        return new JObjectKey(StandardCharsets.UTF_8.decode(buff).toString());
-    }
 }

dhfs-parent/objects/src/main/java/com/usatiuk/objects/JavaDataSerializer.java

@@ -0,0 +1,27 @@
+package com.usatiuk.objects;
+
+
+import com.google.protobuf.ByteString;
+import com.usatiuk.dhfs.utils.SerializationHelper;
+import io.quarkus.arc.DefaultBean;
+import jakarta.enterprise.context.ApplicationScoped;
+
+import java.io.IOException;
+
+@ApplicationScoped
+@DefaultBean
+public class JavaDataSerializer implements ObjectSerializer<JData> {
+    @Override
+    public ByteString serialize(JData obj) {
+        return SerializationHelper.serialize(obj);
+    }
+
+    @Override
+    public JData deserialize(ByteString data) {
+        try (var is = data.newInput()) {
+            return SerializationHelper.deserialize(is);
+        } catch (IOException e) {
+            throw new RuntimeException(e);
+        }
+    }
+}

dhfs-parent/objects/src/main/java/com/usatiuk/objects/ObjectSerializer.java

@@ -1,4 +1,4 @@
-package com.usatiuk.dhfs.objects;
+package com.usatiuk.objects;
 
 import com.google.protobuf.ByteString;
 

dhfs-parent/objects/src/main/java/com/usatiuk/objects/iterators/CloseableKvIterator.java

@@ -1,11 +1,11 @@
-package com.usatiuk.dhfs.objects;
+package com.usatiuk.objects.iterators;
 
 import com.usatiuk.dhfs.utils.AutoCloseableNoThrow;
 import org.apache.commons.lang3.tuple.Pair;
 
 import java.util.Iterator;
 
-public interface CloseableKvIterator<K extends Comparable<K>, V> extends Iterator<Pair<K, V>>, AutoCloseableNoThrow {
+public interface CloseableKvIterator<K extends Comparable<? super K>, V> extends Iterator<Pair<K, V>>, AutoCloseableNoThrow {
     K peekNextKey();
 
     void skip();
@@ -19,6 +19,6 @@ public interface CloseableKvIterator<K extends Comparable<K>, V> extends Iterato
     void skipPrev();
 
     default CloseableKvIterator<K, V> reversed() {
-        return new ReversedKvIterator<>(this);
+        return new ReversedKvIterator<K, V>(this);
     }
 }

dhfs-parent/objects/src/main/java/com/usatiuk/objects/iterators/Data.java

@@ -1,4 +1,4 @@
-package com.usatiuk.dhfs.objects;
+package com.usatiuk.objects.iterators;
 
 import java.util.Optional;
 

dhfs-parent/objects/src/main/java/com/usatiuk/objects/iterators/IterProdFn.java

@@ -1,6 +1,4 @@
-package com.usatiuk.dhfs.objects;
-
-import com.usatiuk.dhfs.objects.persistence.IteratorStart;
+package com.usatiuk.objects.iterators;
 
 @FunctionalInterface
 public interface IterProdFn<K extends Comparable<K>, V> {

dhfs-parent/objects/src/main/java/com/usatiuk/objects/iterators/IteratorStart.java

@@ -1,4 +1,4 @@
-package com.usatiuk.dhfs.objects.persistence;
+package com.usatiuk.objects.iterators;
 
 public enum IteratorStart {
     LT,

dhfs-parent/objects/src/main/java/com/usatiuk/objects/iterators/KeyPredicateKvIterator.java

@@ -1,6 +1,5 @@
-package com.usatiuk.dhfs.objects;
+package com.usatiuk.objects.iterators;
 
-import com.usatiuk.dhfs.objects.persistence.IteratorStart;
 import org.apache.commons.lang3.tuple.Pair;
 
 import java.util.NoSuchElementException;

dhfs-parent/objects/src/main/java/com/usatiuk/objects/iterators/MappingKvIterator.java

@@ -1,4 +1,4 @@
-package com.usatiuk.dhfs.objects;
+package com.usatiuk.objects.iterators;
 
 import org.apache.commons.lang3.tuple.Pair;
 

dhfs-parent/objects/src/main/java/com/usatiuk/objects/iterators/MaybeTombstone.java

@@ -1,4 +1,4 @@
-package com.usatiuk.dhfs.objects;
+package com.usatiuk.objects.iterators;
 
 import java.util.Optional;
 

dhfs-parent/objects/src/main/java/com/usatiuk/objects/iterators/MergingKvIterator.java

@@ -0,0 +1,307 @@
+package com.usatiuk.objects.iterators;
+
+import io.quarkus.logging.Log;
+import org.apache.commons.lang3.tuple.Pair;
+
+import java.util.*;
+import java.util.stream.Collectors;
+
+public class MergingKvIterator<K extends Comparable<K>, V> extends ReversibleKvIterator<K, V> {
+    private final NavigableMap<K, CloseableKvIterator<K, V>> _sortedIterators = new TreeMap<>();
+    private final String _name;
+    private final IteratorStart _initialStartType;
+    private final K _initialStartKey;
+    private final List<IterProdFn<K, V>> _pendingIterators;
+    private Map<CloseableKvIterator<K, V>, Integer> _iterators;
+    // Fast path for the first element
+    private FirstMatchState<K, V> _firstMatchState;
+
+    public MergingKvIterator(String name, IteratorStart startType, K startKey, List<IterProdFn<K, V>> iterators) {
+        _goingForward = true;
+        _name = name;
+        _initialStartType = startType;
+        _initialStartKey = startKey;
+
+        {
+            int counter = 0;
+            var iteratorsTmp = new HashMap<CloseableKvIterator<K, V>, Integer>();
+            for (var iteratorFn : iterators) {
+                var iterator = iteratorFn.get(startType, startKey);
+                if ((counter == 0) // Not really a requirement but simplifies some things for now
+                        && (startType == IteratorStart.GE || startType == IteratorStart.LE)
+                        && iterator.hasNext()
+                        && iterator.peekNextKey().equals(startKey)) {
+                    _firstMatchState = new FirstMatchFound<>(iterator);
+                    _pendingIterators = iterators;
+                    Log.tracev("{0} Created fast match: {1}", _name, _firstMatchState);
+                    return;
+                }
+                iteratorsTmp.put(iterator, counter++);
+            }
+            _iterators = Map.copyOf(iteratorsTmp);
+            _pendingIterators = null;
+        }
+
+        _firstMatchState = new FirstMatchNone<>();
+        doInitialAdvance();
+    }
+
+    @SafeVarargs
+    public MergingKvIterator(String name, IteratorStart startType, K startKey, IterProdFn<K, V>... iterators) {
+        this(name, startType, startKey, List.of(iterators));
+    }
+
+    private void doInitialAdvance() {
+        if (_initialStartType == IteratorStart.LT || _initialStartType == IteratorStart.LE) {
+            // Starting at a greatest key less than/less or equal than:
+            // We have a bunch of iterators that have given us theirs "greatest LT/LE key"
+            // now we need to pick the greatest of those to start with
+            // But if some of them don't have a lesser key, we need to pick the smallest of those
+            var found = _iterators.keySet().stream()
+                    .filter(CloseableKvIterator::hasNext)
+                    .map((i) -> {
+                        var peeked = i.peekNextKey();
+//                            Log.warnv("peeked: {0}, from {1}", peeked, i.getClass());
+                        return peeked;
+                    }).distinct().collect(Collectors.partitioningBy(e -> _initialStartType == IteratorStart.LE ? e.compareTo(_initialStartKey) <= 0 : e.compareTo(_initialStartKey) < 0));
+            K initialMaxValue;
+            if (!found.get(true).isEmpty())
+                initialMaxValue = found.get(true).stream().max(Comparator.naturalOrder()).orElse(null);
+            else
+                initialMaxValue = found.get(false).stream().min(Comparator.naturalOrder()).orElse(null);
+
+            for (var iterator : _iterators.keySet()) {
+                while (iterator.hasNext() && iterator.peekNextKey().compareTo(initialMaxValue) < 0) {
+                    iterator.skip();
+                }
+            }
+        }
+
+        for (CloseableKvIterator<K, V> iterator : _iterators.keySet()) {
+            advanceIterator(iterator);
+        }
+
+        Log.tracev("{0} Initialized: {1}", _name, _sortedIterators);
+        switch (_initialStartType) {
+//            case LT -> {
+//                assert _sortedIterators.isEmpty() || _sortedIterators.firstKey().compareTo(initialStartKey) < 0;
+//            }
+//            case LE -> {
+//                assert _sortedIterators.isEmpty() || _sortedIterators.firstKey().compareTo(initialStartKey) <= 0;
+//            }
+            case GT -> {
+                assert _sortedIterators.isEmpty() || _sortedIterators.firstKey().compareTo(_initialStartKey) > 0;
+            }
+            case GE -> {
+                assert _sortedIterators.isEmpty() || _sortedIterators.firstKey().compareTo(_initialStartKey) >= 0;
+            }
+        }
+    }
+
+    private void doHydrate() {
+        if (_firstMatchState instanceof FirstMatchNone) {
+            return;
+        }
+
+        boolean consumed = _firstMatchState instanceof FirstMatchConsumed;
+        if (_firstMatchState instanceof FirstMatchFound(CloseableKvIterator iterator)) {
+            iterator.close();
+        }
+
+        _firstMatchState = new FirstMatchNone<>();
+
+        {
+            int counter = 0;
+            var iteratorsTmp = new HashMap<CloseableKvIterator<K, V>, Integer>();
+            for (var iteratorFn : _pendingIterators) {
+                var iterator = iteratorFn.get(consumed ? IteratorStart.GT : IteratorStart.GE, _initialStartKey);
+                iteratorsTmp.put(iterator, counter++);
+            }
+            _iterators = Map.copyOf(iteratorsTmp);
+        }
+
+        doInitialAdvance();
+    }
+
+    private void advanceIterator(CloseableKvIterator<K, V> iterator) {
+        if (!iterator.hasNext()) {
+            return;
+        }
+
+        K key = iterator.peekNextKey();
+        Log.tracev("{0} Advance peeked: {1}-{2}", _name, iterator, key);
+        if (!_sortedIterators.containsKey(key)) {
+            _sortedIterators.put(key, iterator);
+            return;
+        }
+
+        // Expects that reversed iterator returns itself when reversed again
+        var oursPrio = _iterators.get(_goingForward ? iterator : iterator.reversed());
+        var them = _sortedIterators.get(key);
+        var theirsPrio = _iterators.get(_goingForward ? them : them.reversed());
+        if (oursPrio < theirsPrio) {
+            _sortedIterators.put(key, iterator);
+            advanceIterator(them);
+        } else {
+            Log.tracev("{0} Skipped: {1}", _name, iterator.peekNextKey());
+            iterator.skip();
+            advanceIterator(iterator);
+        }
+    }
+
+    @Override
+    protected void reverse() {
+        switch (_firstMatchState) {
+            case FirstMatchFound<K, V> firstMatchFound -> {
+                doHydrate();
+            }
+            case FirstMatchConsumed<K, V> firstMatchConsumed -> {
+                doHydrate();
+            }
+            default -> {
+            }
+        }
+
+        var cur = _goingForward ? _sortedIterators.pollFirstEntry() : _sortedIterators.pollLastEntry();
+        Log.tracev("{0} Reversing from {1}", _name, cur);
+        _goingForward = !_goingForward;
+        _sortedIterators.clear();
+        for (CloseableKvIterator<K, V> iterator : _iterators.keySet()) {
+            // _goingForward inverted already
+            advanceIterator(!_goingForward ? iterator.reversed() : iterator);
+        }
+        if (_sortedIterators.isEmpty() || cur == null) {
+            return;
+        }
+        // Advance to the expected key, as we might have brought back some iterators
+        // that were at their ends
+        while (!_sortedIterators.isEmpty()
+                && ((_goingForward && peekImpl().compareTo(cur.getKey()) <= 0)
+                || (!_goingForward && peekImpl().compareTo(cur.getKey()) >= 0))) {
+            skipImpl();
+        }
+        Log.tracev("{0} Reversed to {1}", _name, _sortedIterators);
+    }
+
+    @Override
+    protected K peekImpl() {
+        switch (_firstMatchState) {
+            case FirstMatchFound<K, V> firstMatchFound -> {
+                return firstMatchFound.iterator.peekNextKey();
+            }
+            case FirstMatchConsumed<K, V> firstMatchConsumed -> {
+                doHydrate();
+                break;
+            }
+            default -> {
+            }
+        }
+
+        if (_sortedIterators.isEmpty())
+            throw new NoSuchElementException();
+        return _goingForward ? _sortedIterators.firstKey() : _sortedIterators.lastKey();
+    }
+
+    @Override
+    protected void skipImpl() {
+        switch (_firstMatchState) {
+            case FirstMatchFound<K, V> firstMatchFound -> {
+                var curVal = firstMatchFound.iterator.next();
+                firstMatchFound.iterator.close();
+                _firstMatchState = new FirstMatchConsumed<>();
+//                Log.tracev("{0} Read from {1}: {2}, next: {3}", _name, firstMatchFound.iterator, curVal, _sortedIterators.keySet());
+                return;
+            }
+            case FirstMatchConsumed<K, V> firstMatchConsumed -> {
+                doHydrate();
+                break;
+            }
+            default -> {
+            }
+        }
+
+        var cur = _goingForward ? _sortedIterators.pollFirstEntry() : _sortedIterators.pollLastEntry();
+        if (cur == null) {
+            throw new NoSuchElementException();
+        }
+        cur.getValue().skip();
+        advanceIterator(cur.getValue());
+        Log.tracev("{0} Skip: {1}, next: {2}", _name, cur, _sortedIterators);
+    }
+
+    @Override
+    protected boolean hasImpl() {
+        switch (_firstMatchState) {
+            case FirstMatchFound<K, V> firstMatchFound -> {
+                return true;
+            }
+            case FirstMatchConsumed<K, V> firstMatchConsumed -> {
+                doHydrate();
+                break;
+            }
+            default -> {
+            }
+        }
+        return !_sortedIterators.isEmpty();
+    }
+
+    @Override
+    protected Pair<K, V> nextImpl() {
+        switch (_firstMatchState) {
+            case FirstMatchFound<K, V> firstMatchFound -> {
+                var curVal = firstMatchFound.iterator.next();
+                firstMatchFound.iterator.close();
+                _firstMatchState = new FirstMatchConsumed<>();
+//                Log.tracev("{0} Read from {1}: {2}, next: {3}", _name, firstMatchFound.iterator, curVal, _sortedIterators.keySet());
+                return curVal;
+            }
+            case FirstMatchConsumed<K, V> firstMatchConsumed -> {
+                doHydrate();
+                break;
+            }
+            default -> {
+            }
+        }
+
+        var cur = _goingForward ? _sortedIterators.pollFirstEntry() : _sortedIterators.pollLastEntry();
+        if (cur == null) {
+            throw new NoSuchElementException();
+        }
+        var curVal = cur.getValue().next();
+        advanceIterator(cur.getValue());
+//        Log.tracev("{0} Read from {1}: {2}, next: {3}", _name, cur.getValue(), curVal, _sortedIterators.keySet());
+        return curVal;
+    }
+
+    @Override
+    public void close() {
+        if (_firstMatchState instanceof FirstMatchFound(CloseableKvIterator iterator)) {
+            iterator.close();
+        }
+        for (CloseableKvIterator<K, V> iterator : _iterators.keySet()) {
+            iterator.close();
+        }
+    }
+
+    @Override
+    public String toString() {
+        return "MergingKvIterator{" +
+                "_name='" + _name + '\'' +
+                ", _sortedIterators=" + _sortedIterators.keySet() +
+                ", _iterators=" + _iterators +
+                '}';
+    }
+
+    private interface FirstMatchState<K extends Comparable<K>, V> {
+    }
+
+    private record FirstMatchNone<K extends Comparable<K>, V>() implements FirstMatchState<K, V> {
+    }
+
+    private record FirstMatchFound<K extends Comparable<K>, V>(
+            CloseableKvIterator<K, V> iterator) implements FirstMatchState<K, V> {
+    }
+
+    private record FirstMatchConsumed<K extends Comparable<K>, V>() implements FirstMatchState<K, V> {
+    }
+}

dhfs-parent/objects/src/main/java/com/usatiuk/objects/iterators/NavigableMapKvIterator.java

@@ -1,6 +1,5 @@
-package com.usatiuk.dhfs.objects;
+package com.usatiuk.objects.iterators;
 
-import com.usatiuk.dhfs.objects.persistence.IteratorStart;
 import org.apache.commons.lang3.tuple.Pair;
 
 import java.util.*;

dhfs-parent/objects/src/main/java/com/usatiuk/objects/iterators/PredicateKvIterator.java

@@ -1,6 +1,5 @@
-package com.usatiuk.dhfs.objects;
+package com.usatiuk.objects.iterators;
 
-import com.usatiuk.dhfs.objects.persistence.IteratorStart;
 import io.quarkus.logging.Log;
 import org.apache.commons.lang3.tuple.Pair;
 
@@ -10,12 +9,17 @@ import java.util.function.Function;
 public class PredicateKvIterator<K extends Comparable<K>, V, V_T> extends ReversibleKvIterator<K, V_T> {
     private final CloseableKvIterator<K, V> _backing;
     private final Function<V, V_T> _transformer;
-    private Pair<K, V_T> _next;
+    private Pair<K, V_T> _next = null;
+    private boolean _checkedNext = false;
 
     public PredicateKvIterator(CloseableKvIterator<K, V> backing, IteratorStart start, K startKey, Function<V, V_T> transformer) {
         _goingForward = true;
         _backing = backing;
         _transformer = transformer;
+
+        if (start == IteratorStart.GE || start == IteratorStart.GT)
+            return;
+
         fillNext();
 
         boolean shouldGoBack = false;
@@ -64,6 +68,7 @@ public class PredicateKvIterator<K extends Comparable<K>, V, V_T> extends Revers
                 continue;
             _next = Pair.of(next.getKey(), transformed);
         }
+        _checkedNext = true;
     }
 
     @Override
@@ -80,12 +85,14 @@ public class PredicateKvIterator<K extends Comparable<K>, V, V_T> extends Revers
             Log.tracev("Skipped in reverse: {0}", _next);
 
         _next = null;
-
-        fillNext();
+        _checkedNext = false;
     }
 
     @Override
     protected K peekImpl() {
+        if (!_checkedNext)
+            fillNext();
+
         if (_next == null)
             throw new NoSuchElementException();
         return _next.getKey();
@@ -93,24 +100,33 @@ public class PredicateKvIterator<K extends Comparable<K>, V, V_T> extends Revers
 
     @Override
     protected void skipImpl() {
+        if (!_checkedNext)
+            fillNext();
+
         if (_next == null)
             throw new NoSuchElementException();
         _next = null;
-        fillNext();
+        _checkedNext = false;
     }
 
     @Override
     protected boolean hasImpl() {
+        if (!_checkedNext)
+            fillNext();
+
         return _next != null;
     }
 
     @Override
     protected Pair<K, V_T> nextImpl() {
+        if (!_checkedNext)
+            fillNext();
+
         if (_next == null)
             throw new NoSuchElementException("No more elements");
         var ret = _next;
         _next = null;
-        fillNext();
+        _checkedNext = false;
         return ret;
     }
 

dhfs-parent/objects/src/main/java/com/usatiuk/objects/iterators/ReversedKvIterator.java

@@ -1,8 +1,8 @@
-package com.usatiuk.dhfs.objects;
+package com.usatiuk.objects.iterators;
 
 import org.apache.commons.lang3.tuple.Pair;
 
-public class ReversedKvIterator<K extends Comparable<K>, V> implements CloseableKvIterator<K, V> {
+public class ReversedKvIterator<K extends Comparable<? super K>, V> implements CloseableKvIterator<K, V> {
     private final CloseableKvIterator<K, V> _backing;
 
     public ReversedKvIterator(CloseableKvIterator<K, V> backing) {

dhfs-parent/objects/src/main/java/com/usatiuk/objects/iterators/ReversibleKvIterator.java

@@ -1,4 +1,4 @@
-package com.usatiuk.dhfs.objects;
+package com.usatiuk.objects.iterators;
 
 import org.apache.commons.lang3.tuple.Pair;
 

dhfs-parent/objects/src/main/java/com/usatiuk/objects/iterators/Tombstone.java

@@ -1,4 +1,4 @@
-package com.usatiuk.dhfs.objects;
+package com.usatiuk.objects.iterators;
 
 import java.util.Optional;
 

dhfs-parent/objects/src/main/java/com/usatiuk/objects/iterators/TombstoneMergingKvIterator.java

@@ -1,6 +1,5 @@
-package com.usatiuk.dhfs.objects;
+package com.usatiuk.objects.iterators;
 
-import com.usatiuk.dhfs.objects.persistence.IteratorStart;
 import io.quarkus.logging.Log;
 import org.apache.commons.lang3.tuple.Pair;
 

dhfs-parent/objects/src/main/java/com/usatiuk/objects/snapshot/Snapshot.java

@@ -0,0 +1,18 @@
+package com.usatiuk.objects.snapshot;
+
+import com.usatiuk.objects.JObjectKey;
+import com.usatiuk.objects.iterators.CloseableKvIterator;
+import com.usatiuk.objects.iterators.IteratorStart;
+import com.usatiuk.dhfs.utils.AutoCloseableNoThrow;
+
+import javax.annotation.Nonnull;
+import java.util.Optional;
+
+public interface Snapshot<K extends Comparable<K>, V> extends AutoCloseableNoThrow {
+    CloseableKvIterator<K, V> getIterator(IteratorStart start, K key);
+
+    @Nonnull
+    Optional<V> readObject(K name);
+
+    long id();
+}

dhfs-parent/objects/src/main/java/com/usatiuk/objects/snapshot/SnapshotEntry.java

@@ -1,4 +1,4 @@
-package com.usatiuk.dhfs.objects.snapshot;
+package com.usatiuk.objects.snapshot;
 
 public interface SnapshotEntry {
     long whenToRemove();

dhfs-parent/objects/src/main/java/com/usatiuk/objects/snapshot/SnapshotEntryDeleted.java

@@ -1,4 +1,4 @@
-package com.usatiuk.dhfs.objects.snapshot;
+package com.usatiuk.objects.snapshot;
 
 public record SnapshotEntryDeleted(long whenToRemove) implements SnapshotEntry {
     @Override

dhfs-parent/objects/src/main/java/com/usatiuk/objects/snapshot/SnapshotEntryObject.java

@@ -1,6 +1,6 @@
-package com.usatiuk.dhfs.objects.snapshot;
+package com.usatiuk.objects.snapshot;
 
-import com.usatiuk.dhfs.objects.JDataVersionedWrapper;
+import com.usatiuk.objects.JDataVersionedWrapper;
 
 public record SnapshotEntryObject(JDataVersionedWrapper data, long whenToRemove) implements SnapshotEntry {
     @Override

dhfs-parent/objects/src/main/java/com/usatiuk/objects/snapshot/SnapshotKey.java

@@ -1,6 +1,6 @@
-package com.usatiuk.dhfs.objects.snapshot;
+package com.usatiuk.objects.snapshot;
 
-import com.usatiuk.dhfs.objects.JObjectKey;
+import com.usatiuk.objects.JObjectKey;
 
 import javax.annotation.Nonnull;
 import java.util.Comparator;

dhfs-parent/objects/src/main/java/com/usatiuk/objects/snapshot/SnapshotKvIterator.java

@@ -1,7 +1,9 @@
-package com.usatiuk.dhfs.objects.snapshot;
+package com.usatiuk.objects.snapshot;
 
-import com.usatiuk.dhfs.objects.*;
-import com.usatiuk.dhfs.objects.persistence.IteratorStart;
+import com.usatiuk.objects.JDataVersionedWrapper;
+import com.usatiuk.objects.JObjectKey;
+import com.usatiuk.objects.iterators.*;
+import com.usatiuk.objects.iterators.*;
 import io.quarkus.logging.Log;
 import org.apache.commons.lang3.tuple.Pair;
 
@@ -20,7 +22,12 @@ public class SnapshotKvIterator extends ReversibleKvIterator<JObjectKey, MaybeTo
         _objects = objects;
         _version = version;
         _goingForward = true;
-        _backing = new NavigableMapKvIterator<>(_objects, start, new SnapshotKey(startKey, Long.MIN_VALUE));
+        if (start == IteratorStart.LT || start == IteratorStart.GE)
+            _backing = new NavigableMapKvIterator<>(_objects, start, new SnapshotKey(startKey, Long.MIN_VALUE));
+        else if (start == IteratorStart.GT || start == IteratorStart.LE)
+            _backing = new NavigableMapKvIterator<>(_objects, start, new SnapshotKey(startKey, Long.MAX_VALUE));
+        else
+            throw new UnsupportedOperationException();
         fill();
 
         boolean shouldGoBack = false;

dhfs-parent/objects/src/main/java/com/usatiuk/objects/snapshot/SnapshotManager.java

@@ -0,0 +1,38 @@
+package com.usatiuk.objects.snapshot;
+
+import com.usatiuk.objects.JDataVersionedWrapper;
+import com.usatiuk.objects.JObjectKey;
+import com.usatiuk.objects.stores.WritebackObjectPersistentStore;
+import com.usatiuk.objects.transaction.TxRecord;
+import jakarta.enterprise.context.ApplicationScoped;
+import jakarta.inject.Inject;
+
+import javax.annotation.Nonnull;
+import java.util.Collection;
+import java.util.Optional;
+import java.util.function.Consumer;
+
+@ApplicationScoped
+public class SnapshotManager {
+    @Inject
+    WritebackObjectPersistentStore writebackStore;
+
+    public Snapshot<JObjectKey, JDataVersionedWrapper> createSnapshot() {
+        return writebackStore.getSnapshot();
+    }
+
+    // This should not be called for the same objects concurrently
+    public Consumer<Runnable> commitTx(Collection<TxRecord.TxObjectRecord<?>> writes) {
+        // TODO: FIXME:
+        synchronized (this) {
+            return writebackStore.commitTx(writes, (id, commit) -> {
+                commit.run();
+            });
+        }
+    }
+
+    @Nonnull
+    public Optional<JDataVersionedWrapper> readObjectDirect(JObjectKey name) {
+        return writebackStore.readObject(name);
+    }
+}

dhfs-parent/objects/src/main/java/com/usatiuk/objects/snapshot/SnapshotNavigableMap.java

@@ -0,0 +1,352 @@
+package com.usatiuk.objects.snapshot;
+
+import com.usatiuk.objects.iterators.IteratorStart;
+import jakarta.annotation.Nullable;
+
+import java.util.*;
+
+public class SnapshotNavigableMap<K extends Comparable<K>, V> implements NavigableMap<K, V> {
+
+    private record Bound<K extends Comparable<K>>(K key, boolean inclusive) {
+    }
+
+    private final Snapshot<K, V> _snapshot;
+    @Nullable
+    private final Bound<K> _lowerBound;
+    @Nullable
+    private final Bound<K> _upperBound;
+
+    private SnapshotNavigableMap(Snapshot<K, V> snapshot, Bound<K> lowerBound, Bound<K> upperBound) {
+        _snapshot = snapshot;
+        _lowerBound = lowerBound;
+        _upperBound = upperBound;
+    }
+
+    public SnapshotNavigableMap(Snapshot<K, V> snapshot) {
+        this(snapshot, null, null);
+    }
+
+    private final boolean checkBounds(K key) {
+        if (_lowerBound != null) {
+            if (_lowerBound.inclusive()) {
+                if (key.compareTo(_lowerBound.key()) < 0) {
+                    return false;
+                }
+            } else {
+                if (key.compareTo(_lowerBound.key()) <= 0) {
+                    return false;
+                }
+            }
+        }
+        if (_upperBound != null) {
+            if (_upperBound.inclusive()) {
+                if (key.compareTo(_upperBound.key()) > 0) {
+                    return false;
+                }
+            } else {
+                if (key.compareTo(_upperBound.key()) >= 0) {
+                    return false;
+                }
+            }
+        }
+        return true;
+    }
+
+    @Override
+    public Entry<K, V> lowerEntry(K key) {
+        try (var it = _snapshot.getIterator(IteratorStart.LT, key)) {
+            if (it.hasNext()) {
+                var realKey = it.peekNextKey();
+                if (realKey.compareTo(key) >= 0) {
+                    return null;
+                }
+                if (!checkBounds(realKey)) {
+                    return null;
+                }
+                return it.next();
+            }
+        }
+        return null;
+    }
+
+    @Override
+    public K lowerKey(K key) {
+        try (var it = _snapshot.getIterator(IteratorStart.LT, key)) {
+            if (it.hasNext()) {
+                var realKey = it.peekNextKey();
+                if (realKey.compareTo(key) >= 0) {
+                    return null;
+                }
+                if (!checkBounds(realKey)) {
+                    return null;
+                }
+                return realKey;
+            }
+        }
+        return null;
+    }
+
+    @Override
+    public Entry<K, V> floorEntry(K key) {
+        try (var it = _snapshot.getIterator(IteratorStart.LE, key)) {
+            if (it.hasNext()) {
+                var realKey = it.peekNextKey();
+                if (realKey.compareTo(key) > 0) {
+                    return null;
+                }
+                if (!checkBounds(realKey)) {
+                    return null;
+                }
+                return it.next();
+            }
+        }
+        return null;
+    }
+
+    @Override
+    public K floorKey(K key) {
+        try (var it = _snapshot.getIterator(IteratorStart.LE, key)) {
+            if (it.hasNext()) {
+                var realKey = it.peekNextKey();
+                if (realKey.compareTo(key) > 0) {
+                    return null;
+                }
+                if (!checkBounds(realKey)) {
+                    return null;
+                }
+                return realKey;
+            }
+        }
+        return null;
+    }
+
+    @Override
+    public Entry<K, V> ceilingEntry(K key) {
+        try (var it = _snapshot.getIterator(IteratorStart.GE, key)) {
+            if (it.hasNext()) {
+                var realKey = it.peekNextKey();
+                if (realKey.compareTo(key) < 0) {
+                    return null;
+                }
+                if (!checkBounds(realKey)) {
+                    return null;
+                }
+                return it.next();
+            }
+        }
+        return null;
+    }
+
+    @Override
+    public K ceilingKey(K key) {
+        try (var it = _snapshot.getIterator(IteratorStart.GE, key)) {
+            if (it.hasNext()) {
+                var realKey = it.peekNextKey();
+                if (realKey.compareTo(key) < 0) {
+                    return null;
+                }
+                if (!checkBounds(realKey)) {
+                    return null;
+                }
+                return realKey;
+            }
+        }
+        return null;
+    }
+
+    @Override
+    public Entry<K, V> higherEntry(K key) {
+        try (var it = _snapshot.getIterator(IteratorStart.GT, key)) {
+            if (it.hasNext()) {
+                var realKey = it.peekNextKey();
+                if (realKey.compareTo(key) <= 0) {
+                    return null;
+                }
+                if (!checkBounds(realKey)) {
+                    return null;
+                }
+                return it.next();
+            }
+        }
+        return null;
+    }
+
+    @Override
+    public K higherKey(K key) {
+        try (var it = _snapshot.getIterator(IteratorStart.GT, key)) {
+            if (it.hasNext()) {
+                var realKey = it.peekNextKey();
+                if (realKey.compareTo(key) <= 0) {
+                    return null;
+                }
+                if (!checkBounds(realKey)) {
+                    return null;
+                }
+                return realKey;
+            }
+        }
+        return null;
+    }
+
+    @Override
+    public Entry<K, V> firstEntry() {
+        var lb = _lowerBound == null ? null : _lowerBound.key();
+        var start = _lowerBound != null ? (_lowerBound.inclusive() ? IteratorStart.GE : IteratorStart.GT) : IteratorStart.GE;
+        try (var it = _snapshot.getIterator(start, lb)) {
+            if (it.hasNext()) {
+                var realKey = it.peekNextKey();
+                if (!checkBounds(realKey)) {
+                    return null;
+                }
+                return it.next();
+            }
+        }
+        return null;
+    }
+
+    @Override
+    public Entry<K, V> lastEntry() {
+        var b = _upperBound == null ? null : _upperBound.key();
+        var start = _upperBound != null ? (_upperBound.inclusive() ? IteratorStart.LE : IteratorStart.LT) : IteratorStart.LE;
+        try (var it = _snapshot.getIterator(start, b)) {
+            if (it.hasNext()) {
+                var realKey = it.peekNextKey();
+                if (!checkBounds(realKey)) {
+                    return null;
+                }
+                return it.next();
+            }
+        }
+        return null;
+    }
+
+    @Override
+    public Entry<K, V> pollFirstEntry() {
+        throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public Entry<K, V> pollLastEntry() {
+        throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public NavigableMap<K, V> descendingMap() {
+        return null;
+    }
+
+    @Override
+    public NavigableSet<K> navigableKeySet() {
+        return null;
+    }
+
+    @Override
+    public NavigableSet<K> descendingKeySet() {
+        return null;
+    }
+
+    @Override
+    public NavigableMap<K, V> subMap(K fromKey, boolean fromInclusive, K toKey, boolean toInclusive) {
+        return null;
+    }
+
+    @Override
+    public NavigableMap<K, V> headMap(K toKey, boolean inclusive) {
+        return null;
+    }
+
+    @Override
+    public NavigableMap<K, V> tailMap(K fromKey, boolean inclusive) {
+        return null;
+    }
+
+    @Override
+    public Comparator<? super K> comparator() {
+        return null;
+    }
+
+    @Override
+    public SortedMap<K, V> subMap(K fromKey, K toKey) {
+        return null;
+    }
+
+    @Override
+    public SortedMap<K, V> headMap(K toKey) {
+        return null;
+    }
+
+    @Override
+    public SortedMap<K, V> tailMap(K fromKey) {
+        return null;
+    }
+
+    @Override
+    public K firstKey() {
+        return null;
+    }
+
+    @Override
+    public K lastKey() {
+        return null;
+    }
+
+    @Override
+    public int size() {
+        return 0;
+    }
+
+    @Override
+    public boolean isEmpty() {
+        return false;
+    }
+
+    @Override
+    public boolean containsKey(Object key) {
+        return false;
+    }
+
+    @Override
+    public boolean containsValue(Object value) {
+        return false;
+    }
+
+    @Override
+    public V get(Object key) {
+        return null;
+    }
+
+    @Override
+    public V put(K key, V value) {
+        return null;
+    }
+
+    @Override
+    public V remove(Object key) {
+        return null;
+    }
+
+    @Override
+    public void putAll(Map<? extends K, ? extends V> m) {
+
+    }
+
+    @Override
+    public void clear() {
+
+    }
+
+    @Override
+    public Set<K> keySet() {
+        return Set.of();
+    }
+
+    @Override
+    public Collection<V> values() {
+        return List.of();
+    }
+
+    @Override
+    public Set<Entry<K, V>> entrySet() {
+        return Set.of();
+    }
+}

dhfs-parent/objects/src/main/java/com/usatiuk/objects/stores/CachingObjectPersistentStore.java

@@ -0,0 +1,294 @@
+package com.usatiuk.objects.stores;
+
+import com.usatiuk.objects.JDataVersionedWrapper;
+import com.usatiuk.objects.JObjectKey;
+import com.usatiuk.objects.iterators.*;
+import com.usatiuk.objects.iterators.*;
+import com.usatiuk.objects.snapshot.Snapshot;
+import com.usatiuk.objects.transaction.LockManager;
+import io.quarkus.logging.Log;
+import io.quarkus.runtime.Startup;
+import jakarta.enterprise.context.ApplicationScoped;
+import jakarta.inject.Inject;
+import org.apache.commons.lang3.tuple.Pair;
+import org.eclipse.microprofile.config.inject.ConfigProperty;
+import org.pcollections.TreePMap;
+
+import javax.annotation.Nonnull;
+import java.util.LinkedHashMap;
+import java.util.Optional;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.concurrent.locks.ReentrantReadWriteLock;
+
+@ApplicationScoped
+public class CachingObjectPersistentStore {
+    private final LinkedHashMap<JObjectKey, CacheEntry> _cache = new LinkedHashMap<>();
+    private final ReentrantReadWriteLock _lock = new ReentrantReadWriteLock();
+    @Inject
+    LockManager lockManager;
+    @Inject
+    SerializingObjectPersistentStore delegate;
+    @ConfigProperty(name = "dhfs.objects.lru.limit")
+    long sizeLimit;
+    @ConfigProperty(name = "dhfs.objects.lru.print-stats")
+    boolean printStats;
+    private TreePMap<JObjectKey, CacheEntry> _sortedCache = TreePMap.empty();
+    private long _cacheVersion = 0;
+    private long _curSize = 0;
+    private long _evict = 0;
+
+    private ExecutorService _statusExecutor = null;
+
+    @Startup
+    void init() {
+        if (printStats) {
+            _statusExecutor = Executors.newSingleThreadExecutor();
+            _statusExecutor.submit(() -> {
+                try {
+                    while (true) {
+                        Thread.sleep(10000);
+                        if (_curSize > 0)
+                            Log.info("Cache status: size=" + _curSize / 1024 / 1024 + "MB" + " evicted=" + _evict);
+                        _evict = 0;
+                    }
+                } catch (InterruptedException ignored) {
+                }
+            });
+        }
+    }
+
+    private void put(JObjectKey key, Optional<JDataVersionedWrapper> obj) {
+//        Log.tracev("Adding {0} to cache: {1}", key, obj);
+        _lock.writeLock().lock();
+        try {
+            int size = obj.map(JDataVersionedWrapper::estimateSize).orElse(16);
+
+            _curSize += size;
+            var entry = new CacheEntry(obj.<MaybeTombstone<JDataVersionedWrapper>>map(Data::new).orElse(new Tombstone<>()), size);
+            var old = _cache.putLast(key, entry);
+
+            _sortedCache = _sortedCache.plus(key, entry);
+            if (old != null)
+                _curSize -= old.size();
+
+            while (_curSize >= sizeLimit) {
+                var del = _cache.pollFirstEntry();
+                _sortedCache = _sortedCache.minus(del.getKey());
+                _curSize -= del.getValue().size();
+                _evict++;
+            }
+        } finally {
+            _lock.writeLock().unlock();
+        }
+    }
+
+    @Nonnull
+    public Optional<JDataVersionedWrapper> readObject(JObjectKey name) {
+        _lock.readLock().lock();
+        try {
+            var got = _cache.get(name);
+            if (got != null) {
+                return got.object().opt();
+            }
+        } finally {
+            _lock.readLock().unlock();
+        }
+        // Global object lock, prevent putting the object into cache
+        // if its being written right now by another thread
+        try (var lock = lockManager.tryLockObject(name)) {
+            var got = delegate.readObject(name);
+
+            if (lock == null)
+                return got;
+
+            _lock.writeLock().lock();
+            try {
+                put(name, got);
+                // No need to increase cache version, the objects didn't change
+            } finally {
+                _lock.writeLock().unlock();
+            }
+            return got;
+        }
+    }
+
+    public void commitTx(TxManifestObj<? extends JDataVersionedWrapper> names, long txId) {
+        var serialized = delegate.prepareManifest(names);
+
+        Log.tracev("Committing: {0} writes, {1} deletes", names.written().size(), names.deleted().size());
+        // A little complicated locking to minimize write lock holding time
+        delegate.commitTx(serialized, txId, (commit) -> {
+            _lock.writeLock().lock();
+            try {
+                // Make the changes visible atomically both in cache and in the underlying store
+                for (var write : names.written()) {
+                    put(write.getLeft(), Optional.of(write.getRight()));
+                }
+                for (var del : names.deleted()) {
+                    put(del, Optional.empty());
+                }
+                ++_cacheVersion;
+                commit.run();
+            } finally {
+                _lock.writeLock().unlock();
+            }
+        });
+        Log.tracev("Committed: {0} writes, {1} deletes", names.written().size(), names.deleted().size());
+    }
+
+    public Snapshot<JObjectKey, JDataVersionedWrapper> getSnapshot() {
+        TreePMap<JObjectKey, CacheEntry> curSortedCache;
+        Snapshot<JObjectKey, JDataVersionedWrapper> backing = null;
+        long cacheVersion;
+
+        try {
+//            Log.tracev("Getting cache snapshot");
+            // Decrease the lock time as much as possible
+            _lock.readLock().lock();
+            try {
+                curSortedCache = _sortedCache;
+                cacheVersion = _cacheVersion;
+                // TODO: Could this be done without lock?
+                backing = delegate.getSnapshot();
+            } finally {
+                _lock.readLock().unlock();
+            }
+
+            Snapshot<JObjectKey, JDataVersionedWrapper> finalBacking = backing;
+            return new Snapshot<JObjectKey, JDataVersionedWrapper>() {
+                private final TreePMap<JObjectKey, CacheEntry> _curSortedCache = curSortedCache;
+                private final Snapshot<JObjectKey, JDataVersionedWrapper> _backing = finalBacking;
+                private final long _snapshotCacheVersion = cacheVersion;
+
+                private void maybeCache(JObjectKey key, Optional<JDataVersionedWrapper> obj) {
+                    if (_snapshotCacheVersion != _cacheVersion)
+                        return;
+
+                    _lock.writeLock().lock();
+                    try {
+                        if (_snapshotCacheVersion != _cacheVersion) {
+//                            Log.tracev("Not caching: {0}", key);
+                        } else {
+//                            Log.tracev("Caching: {0}", key);
+                            put(key, obj);
+                        }
+                    } finally {
+                        _lock.writeLock().unlock();
+                    }
+                }
+
+                @Override
+                public CloseableKvIterator<JObjectKey, JDataVersionedWrapper> getIterator(IteratorStart start, JObjectKey key) {
+                    return new TombstoneMergingKvIterator<>("cache", start, key,
+                            (mS, mK)
+                                    -> new MappingKvIterator<>(
+                                    new NavigableMapKvIterator<>(_curSortedCache, mS, mK),
+                                    e -> {
+//                                        Log.tracev("Taken from cache: {0}", e);
+                                        return e.object();
+                                    }
+                            ),
+                            (mS, mK) -> new MappingKvIterator<>(new CachingKvIterator(_backing.getIterator(start, key)), Data::new));
+                }
+
+                @Nonnull
+                @Override
+                public Optional<JDataVersionedWrapper> readObject(JObjectKey name) {
+                    var cached = _curSortedCache.get(name);
+                    if (cached != null) {
+                        return switch (cached.object()) {
+                            case Data<JDataVersionedWrapper> data -> Optional.of(data.value());
+                            case Tombstone<JDataVersionedWrapper> tombstone -> {
+                                yield Optional.empty();
+                            }
+                            default -> throw new IllegalStateException("Unexpected value: " + cached.object());
+                        };
+                    }
+                    var read = _backing.readObject(name);
+                    maybeCache(name, read);
+                    return _backing.readObject(name);
+                }
+
+                @Override
+                public long id() {
+                    return _backing.id();
+                }
+
+                @Override
+                public void close() {
+                    _backing.close();
+                }
+
+                private class CachingKvIterator implements CloseableKvIterator<JObjectKey, JDataVersionedWrapper> {
+                    private final CloseableKvIterator<JObjectKey, JDataVersionedWrapper> _delegate;
+
+                    private CachingKvIterator(CloseableKvIterator<JObjectKey, JDataVersionedWrapper> delegate) {
+                        _delegate = delegate;
+                    }
+
+                    @Override
+                    public JObjectKey peekNextKey() {
+                        return _delegate.peekNextKey();
+                    }
+
+                    @Override
+                    public void skip() {
+                        _delegate.skip();
+                    }
+
+                    @Override
+                    public void close() {
+                        _delegate.close();
+                    }
+
+                    @Override
+                    public boolean hasNext() {
+                        return _delegate.hasNext();
+                    }
+
+                    @Override
+                    public JObjectKey peekPrevKey() {
+                        return _delegate.peekPrevKey();
+                    }
+
+                    @Override
+                    public Pair<JObjectKey, JDataVersionedWrapper> prev() {
+                        var prev = _delegate.prev();
+                        maybeCache(prev.getKey(), Optional.of(prev.getValue()));
+                        return prev;
+                    }
+
+                    @Override
+                    public boolean hasPrev() {
+                        return _delegate.hasPrev();
+                    }
+
+                    @Override
+                    public void skipPrev() {
+                        _delegate.skipPrev();
+                    }
+
+                    @Override
+                    public Pair<JObjectKey, JDataVersionedWrapper> next() {
+                        var next = _delegate.next();
+                        maybeCache(next.getKey(), Optional.of(next.getValue()));
+                        return next;
+                    }
+                }
+            };
+        } catch (Throwable ex) {
+            if (backing != null) {
+                backing.close();
+            }
+            throw ex;
+        }
+    }
+
+    public long getLastTxId() {
+        return delegate.getLastCommitId();
+    }
+
+    private record CacheEntry(MaybeTombstone<JDataVersionedWrapper> object, long size) {
+    }
+}

dhfs-parent/objects/src/main/java/com/usatiuk/objects/stores/LmdbObjectPersistentStore.java

@@ -1,10 +1,12 @@
-package com.usatiuk.dhfs.objects.persistence;
+package com.usatiuk.objects.stores;
 
 import com.google.protobuf.ByteString;
-import com.usatiuk.dhfs.objects.CloseableKvIterator;
-import com.usatiuk.dhfs.objects.JObjectKey;
-import com.usatiuk.dhfs.objects.KeyPredicateKvIterator;
-import com.usatiuk.dhfs.objects.ReversibleKvIterator;
+import com.usatiuk.objects.JObjectKey;
+import com.usatiuk.objects.iterators.CloseableKvIterator;
+import com.usatiuk.objects.iterators.IteratorStart;
+import com.usatiuk.objects.iterators.KeyPredicateKvIterator;
+import com.usatiuk.objects.iterators.ReversibleKvIterator;
+import com.usatiuk.objects.snapshot.Snapshot;
 import com.usatiuk.dhfs.supportlib.UninitializedByteBuffer;
 import com.usatiuk.dhfs.utils.RefcountedCloseable;
 import io.quarkus.arc.properties.IfBuildProperty;
@@ -25,7 +27,9 @@ import java.lang.ref.Cleaner;
 import java.nio.ByteBuffer;
 import java.nio.charset.StandardCharsets;
 import java.nio.file.Path;
-import java.util.*;
+import java.util.Arrays;
+import java.util.NoSuchElementException;
+import java.util.Optional;
 import java.util.concurrent.atomic.AtomicReference;
 import java.util.concurrent.locks.ReentrantReadWriteLock;
 import java.util.function.Consumer;
@@ -36,19 +40,16 @@ import static org.lmdbjava.Env.create;
 @ApplicationScoped
 @IfBuildProperty(name = "dhfs.objects.persistence", stringValue = "lmdb")
 public class LmdbObjectPersistentStore implements ObjectPersistentStore {
+    private static final String DB_NAME = "objects";
+    private static final byte[] DB_VER_OBJ_NAME = "__DB_VER_OBJ".getBytes(StandardCharsets.UTF_8);
     private final Path _root;
+    private final AtomicReference<RefcountedCloseable<Txn<ByteBuffer>>> _curReadTxn = new AtomicReference<>();
+    private final ReentrantReadWriteLock _lock = new ReentrantReadWriteLock();
     private Env<ByteBuffer> _env;
     private Dbi<ByteBuffer> _db;
     private boolean _ready = false;
-    private final AtomicReference<RefcountedCloseable<Txn<ByteBuffer>>> _curReadTxn = new AtomicReference<>();
-
     private long _lastTxId = 0;
 
-    private final ReentrantReadWriteLock _lock = new ReentrantReadWriteLock();
-
-    private static final String DB_NAME = "objects";
-    private static final byte[] DB_VER_OBJ_NAME = "__DB_VER_OBJ".getBytes(StandardCharsets.UTF_8);
-
     public LmdbObjectPersistentStore(@ConfigProperty(name = "dhfs.objects.persistence.files.root") String root) {
         _root = Path.of(root).resolve("objects");
     }
@@ -90,22 +91,6 @@ public class LmdbObjectPersistentStore implements ObjectPersistentStore {
         if (!_ready) throw new IllegalStateException("Wrong service order!");
     }
 
-    @Nonnull
-    @Override
-    public Collection<JObjectKey> findAllObjects() {
-//        try (Txn<ByteBuffer> txn = env.txnRead()) {
-//            try (var cursor = db.openCursor(txn)) {
-//                var keys = List.of();
-//                while (cursor.next()) {
-//                    keys.add(JObjectKey.fromBytes(cursor.key()));
-//                }
-//                return keys;
-//            }
-//        }
-        return List.of();
-    }
-
-
     @Nonnull
     @Override
     public Optional<ByteString> readObject(JObjectKey name) {
@@ -116,33 +101,157 @@ public class LmdbObjectPersistentStore implements ObjectPersistentStore {
         }
     }
 
+    private RefcountedCloseable<Txn<ByteBuffer>> getCurTxn() {
+        _lock.readLock().lock();
+        try {
+            var got = _curReadTxn.get();
+            var refInc = Optional.ofNullable(got).map(RefcountedCloseable::ref).orElse(null);
+            if (refInc != null) {
+                return got;
+            } else {
+                var newTxn = new RefcountedCloseable<>(_env.txnRead());
+                _curReadTxn.compareAndSet(got, newTxn);
+                return newTxn;
+            }
+        } finally {
+            _lock.readLock().unlock();
+        }
+    }
+
+    @Override
+    public CloseableKvIterator<JObjectKey, ByteString> getIterator(IteratorStart start, JObjectKey key) {
+        return new KeyPredicateKvIterator<>(new LmdbKvIterator(start, key), start, key, (k) -> !Arrays.equals(k.name().getBytes(StandardCharsets.UTF_8), DB_VER_OBJ_NAME));
+    }
+
+    @Override
+    public Snapshot<JObjectKey, ByteString> getSnapshot() {
+        _lock.readLock().lock();
+        try {
+            var txn = new RefcountedCloseable<>(_env.txnRead());
+            var commitId = getLastCommitId();
+            return new Snapshot<JObjectKey, ByteString>() {
+                private final RefcountedCloseable<Txn<ByteBuffer>> _txn = txn;
+                private final long _id = commitId;
+                private boolean _closed = false;
+
+                @Override
+                public CloseableKvIterator<JObjectKey, ByteString> getIterator(IteratorStart start, JObjectKey key) {
+                    assert !_closed;
+                    return new KeyPredicateKvIterator<>(new LmdbKvIterator(_txn.ref(), start, key), start, key, (k) -> !Arrays.equals(k.name().getBytes(StandardCharsets.UTF_8), DB_VER_OBJ_NAME));
+                }
+
+                @Nonnull
+                @Override
+                public Optional<ByteString> readObject(JObjectKey name) {
+                    assert !_closed;
+                    var got = _db.get(_txn.get(), name.toByteBuffer());
+                    var ret = Optional.ofNullable(got).map(ByteString::copyFrom);
+                    return ret;
+                }
+
+                @Override
+                public long id() {
+                    assert !_closed;
+                    return _id;
+                }
+
+                @Override
+                public void close() {
+                    assert !_closed;
+                    _closed = true;
+                    _txn.unref();
+                }
+            };
+        } finally {
+            _lock.readLock().unlock();
+        }
+    }
+
+    @Override
+    public void commitTx(TxManifestRaw names, long txId, Consumer<Runnable> commitLocked) {
+        verifyReady();
+        try (Txn<ByteBuffer> txn = _env.txnWrite()) {
+            for (var written : names.written()) {
+                // TODO:
+                var bb = UninitializedByteBuffer.allocateUninitialized(written.getValue().size());
+                bb.put(written.getValue().asReadOnlyByteBuffer());
+                bb.flip();
+                _db.put(txn, written.getKey().toByteBuffer(), bb);
+            }
+            for (JObjectKey key : names.deleted()) {
+                _db.delete(txn, key.toByteBuffer());
+            }
+
+            var bb = ByteBuffer.allocateDirect(DB_VER_OBJ_NAME.length);
+            bb.put(DB_VER_OBJ_NAME);
+            bb.flip();
+            var bbData = ByteBuffer.allocateDirect(8);
+
+            commitLocked.accept(() -> {
+                _lock.writeLock().lock();
+                try {
+                    var realTxId = txId;
+                    if (realTxId == -1)
+                        realTxId = _lastTxId + 1;
+
+                    assert realTxId > _lastTxId;
+                    _lastTxId = realTxId;
+
+                    bbData.putLong(realTxId);
+                    bbData.flip();
+                    _db.put(txn, bb, bbData);
+
+                    _curReadTxn.set(null);
+
+                    txn.commit();
+                } finally {
+                    _lock.writeLock().unlock();
+                }
+            });
+        }
+    }
+
+    @Override
+    public long getTotalSpace() {
+        verifyReady();
+        return _root.toFile().getTotalSpace();
+    }
+
+    @Override
+    public long getFreeSpace() {
+        verifyReady();
+        return _root.toFile().getFreeSpace();
+    }
+
+    @Override
+    public long getUsableSpace() {
+        verifyReady();
+        return _root.toFile().getUsableSpace();
+    }
+
+    @Override
+    public long getLastCommitId() {
+        _lock.readLock().lock();
+        try {
+            return _lastTxId;
+        } finally {
+            _lock.readLock().unlock();
+        }
+    }
+
     private class LmdbKvIterator extends ReversibleKvIterator<JObjectKey, ByteString> {
+        private static final Cleaner CLEANER = Cleaner.create();
         private final RefcountedCloseable<Txn<ByteBuffer>> _txn;
         private final Cursor<ByteBuffer> _cursor;
-        private boolean _hasNext = false;
-
-        private static final Cleaner CLEANER = Cleaner.create();
         private final MutableObject<Boolean> _closed = new MutableObject<>(false);
         //        private final Exception _allocationStacktrace = new Exception();
         private final Exception _allocationStacktrace = null;
+        private boolean _hasNext = false;
 
-        LmdbKvIterator(IteratorStart start, JObjectKey key) {
+        LmdbKvIterator(RefcountedCloseable<Txn<ByteBuffer>> txn, IteratorStart start, JObjectKey key) {
+            _txn = txn;
             _goingForward = true;
 
-            _lock.readLock().lock();
-            try {
-                var got = _curReadTxn.get();
-                var refInc = Optional.ofNullable(got).map(RefcountedCloseable::ref).orElse(null);
-                if (refInc != null) {
-                    _txn = got;
-                } else {
-                    var newTxn = new RefcountedCloseable<>(_env.txnRead());
-                    _curReadTxn.compareAndSet(got, newTxn);
-                    _txn = newTxn;
-                }
-            } finally {
-                _lock.readLock().unlock();
-            }
             _cursor = _db.openCursor(_txn.get());
 
             var closedRef = _closed;
@@ -155,7 +264,10 @@ public class LmdbObjectPersistentStore implements ObjectPersistentStore {
             });
 
             verifyReady();
-            if (!_cursor.get(key.toByteBuffer(), GetOp.MDB_SET_RANGE)) {
+            if (key.toByteBuffer().remaining() == 0) {
+                if (!_cursor.first())
+                    return;
+            } else if (!_cursor.get(key.toByteBuffer(), GetOp.MDB_SET_RANGE)) {
                 return;
             }
 
@@ -214,6 +326,10 @@ public class LmdbObjectPersistentStore implements ObjectPersistentStore {
             Log.tracev("got: {0}, hasNext: {1}", realGot, _hasNext);
         }
 
+        LmdbKvIterator(IteratorStart start, JObjectKey key) {
+            this(getCurTxn(), start, key);
+        }
+
         @Override
         public void close() {
             if (_closed.getValue()) {
@@ -287,81 +403,4 @@ public class LmdbObjectPersistentStore implements ObjectPersistentStore {
         }
     }
 
-    @Override
-    public CloseableKvIterator<JObjectKey, ByteString> getIterator(IteratorStart start, JObjectKey key) {
-        return new KeyPredicateKvIterator<>(new LmdbKvIterator(start, key), start, key, (k) -> !Arrays.equals(k.name().getBytes(StandardCharsets.UTF_8), DB_VER_OBJ_NAME));
-    }
-
-    @Override
-    public void commitTx(TxManifestRaw names, long txId, Consumer<Runnable> commitLocked) {
-        verifyReady();
-        try (Txn<ByteBuffer> txn = _env.txnWrite()) {
-            for (var written : names.written()) {
-                // TODO:
-                var bb = UninitializedByteBuffer.allocateUninitialized(written.getValue().size());
-                bb.put(written.getValue().asReadOnlyByteBuffer());
-                bb.flip();
-                _db.put(txn, written.getKey().toByteBuffer(), bb);
-            }
-            for (JObjectKey key : names.deleted()) {
-                _db.delete(txn, key.toByteBuffer());
-            }
-
-            var bb = ByteBuffer.allocateDirect(DB_VER_OBJ_NAME.length);
-            bb.put(DB_VER_OBJ_NAME);
-            bb.flip();
-            var bbData = ByteBuffer.allocateDirect(8);
-
-            commitLocked.accept(() -> {
-                _lock.writeLock().lock();
-                try {
-                    var realTxId = txId;
-                    if (realTxId == -1)
-                        realTxId = _lastTxId + 1;
-
-                    assert realTxId > _lastTxId;
-                    _lastTxId = realTxId;
-
-                    bbData.putLong(realTxId);
-                    bbData.flip();
-                    _db.put(txn, bb, bbData);
-
-                    _curReadTxn.set(null);
-
-                    txn.commit();
-                } finally {
-                    _lock.writeLock().unlock();
-                }
-            });
-        }
-    }
-
-    @Override
-    public long getTotalSpace() {
-        verifyReady();
-        return _root.toFile().getTotalSpace();
-    }
-
-    @Override
-    public long getFreeSpace() {
-        verifyReady();
-        return _root.toFile().getFreeSpace();
-    }
-
-    @Override
-    public long getUsableSpace() {
-        verifyReady();
-        return _root.toFile().getUsableSpace();
-    }
-
-    @Override
-    public long getLastCommitId() {
-        _lock.readLock().lock();
-        try {
-            return _lastTxId;
-        } finally {
-            _lock.readLock().unlock();
-        }
-    }
-
 }

dhfs-parent/objects/src/main/java/com/usatiuk/objects/stores/MemoryObjectPersistentStore.java

@@ -1,33 +1,26 @@
-package com.usatiuk.dhfs.objects.persistence;
+package com.usatiuk.objects.stores;
 
 import com.google.protobuf.ByteString;
-import com.usatiuk.dhfs.objects.CloseableKvIterator;
-import com.usatiuk.dhfs.objects.JObjectKey;
-import com.usatiuk.dhfs.objects.NavigableMapKvIterator;
+import com.usatiuk.objects.JObjectKey;
+import com.usatiuk.objects.iterators.CloseableKvIterator;
+import com.usatiuk.objects.iterators.IteratorStart;
+import com.usatiuk.objects.iterators.NavigableMapKvIterator;
+import com.usatiuk.objects.snapshot.Snapshot;
 import io.quarkus.arc.properties.IfBuildProperty;
 import jakarta.enterprise.context.ApplicationScoped;
+import org.pcollections.TreePMap;
 
 import javax.annotation.Nonnull;
-import java.util.Collection;
 import java.util.Optional;
-import java.util.concurrent.ConcurrentSkipListMap;
 import java.util.concurrent.locks.ReentrantReadWriteLock;
 import java.util.function.Consumer;
 
 @ApplicationScoped
 @IfBuildProperty(name = "dhfs.objects.persistence", stringValue = "memory")
 public class MemoryObjectPersistentStore implements ObjectPersistentStore {
-    private final ConcurrentSkipListMap<JObjectKey, ByteString> _objects = new ConcurrentSkipListMap<>();
-    private long _lastCommitId = 0;
     private final ReentrantReadWriteLock _lock = new ReentrantReadWriteLock();
-
-    @Nonnull
-    @Override
-    public Collection<JObjectKey> findAllObjects() {
-        synchronized (this) {
-            return _objects.keySet();
-        }
-    }
+    private TreePMap<JObjectKey, ByteString> _objects = TreePMap.empty();
+    private long _lastCommitId = 0;
 
     @Nonnull
     @Override
@@ -42,14 +35,45 @@ public class MemoryObjectPersistentStore implements ObjectPersistentStore {
         return new NavigableMapKvIterator<>(_objects, start, key);
     }
 
+    @Override
+    public Snapshot<JObjectKey, ByteString> getSnapshot() {
+        synchronized (this) {
+            return new Snapshot<JObjectKey, ByteString>() {
+                private final TreePMap<JObjectKey, ByteString> _objects = MemoryObjectPersistentStore.this._objects;
+                private final long _lastCommitId = MemoryObjectPersistentStore.this._lastCommitId;
+
+                @Override
+                public CloseableKvIterator<JObjectKey, ByteString> getIterator(IteratorStart start, JObjectKey key) {
+                    return new NavigableMapKvIterator<>(_objects, start, key);
+                }
+
+                @Nonnull
+                @Override
+                public Optional<ByteString> readObject(JObjectKey name) {
+                    return Optional.ofNullable(_objects.get(name));
+                }
+
+                @Override
+                public long id() {
+                    return _lastCommitId;
+                }
+
+                @Override
+                public void close() {
+
+                }
+            };
+        }
+    }
+
     @Override
     public void commitTx(TxManifestRaw names, long txId, Consumer<Runnable> commitLocked) {
         synchronized (this) {
             for (var written : names.written()) {
-                _objects.put(written.getKey(), written.getValue());
+                _objects = _objects.plus(written.getKey(), written.getValue());
             }
             for (JObjectKey key : names.deleted()) {
-                _objects.remove(key);
+                _objects = _objects.minus(key);
             }
             commitLocked.accept(() -> {
                 _lock.writeLock().lock();

dhfs-parent/objects/src/main/java/com/usatiuk/objects/stores/ObjectPersistentStore.java

@@ -1,20 +1,18 @@
-package com.usatiuk.dhfs.objects.persistence;
+package com.usatiuk.objects.stores;
 
 import com.google.protobuf.ByteString;
-import com.usatiuk.dhfs.objects.CloseableKvIterator;
-import com.usatiuk.dhfs.objects.JObjectKey;
+import com.usatiuk.objects.JObjectKey;
+import com.usatiuk.objects.iterators.CloseableKvIterator;
+import com.usatiuk.objects.iterators.IteratorStart;
+import com.usatiuk.objects.snapshot.Snapshot;
 
 import javax.annotation.Nonnull;
-import java.util.Collection;
 import java.util.Optional;
 import java.util.function.Consumer;
 
 // Persistent storage of objects
 // All changes are written as sequential transactions
 public interface ObjectPersistentStore {
-    @Nonnull
-    Collection<JObjectKey> findAllObjects();
-
     @Nonnull
     Optional<ByteString> readObject(JObjectKey name);
 
@@ -22,6 +20,8 @@ public interface ObjectPersistentStore {
     // Does not have to guarantee consistent view, snapshots are handled by upper layers
     CloseableKvIterator<JObjectKey, ByteString> getIterator(IteratorStart start, JObjectKey key);
 
+    Snapshot<JObjectKey, ByteString> getSnapshot();
+
     /**
      * @param commitLocked - a function that will be called with a Runnable that will commit the transaction
      *                     the changes in the store will be visible to new transactions only after the runnable is called

dhfs-parent/objects/src/main/java/com/usatiuk/objects/stores/PendingDelete.java

@@ -1,4 +1,6 @@
-package com.usatiuk.dhfs.objects;
+package com.usatiuk.objects.stores;
+
+import com.usatiuk.objects.JObjectKey;
 
 public record PendingDelete(JObjectKey key, long bundleId) implements PendingWriteEntry {
 }

dhfs-parent/objects/src/main/java/com/usatiuk/objects/stores/PendingWrite.java

@@ -1,4 +1,6 @@
-package com.usatiuk.dhfs.objects;
+package com.usatiuk.objects.stores;
+
+import com.usatiuk.objects.JDataVersionedWrapper;
 
 public record PendingWrite(JDataVersionedWrapper data, long bundleId) implements PendingWriteEntry {
 }

dhfs-parent/objects/src/main/java/com/usatiuk/objects/stores/PendingWriteEntry.java

@@ -1,4 +1,4 @@
-package com.usatiuk.dhfs.objects;
+package com.usatiuk.objects.stores;
 
 public interface PendingWriteEntry {
     long bundleId();

dhfs-parent/objects/src/main/java/com/usatiuk/objects/stores/SerializingObjectPersistentStore.java

@@ -0,0 +1,80 @@
+package com.usatiuk.objects.stores;
+
+import com.google.protobuf.ByteString;
+import com.usatiuk.objects.JDataVersionedWrapper;
+import com.usatiuk.objects.JObjectKey;
+import com.usatiuk.objects.ObjectSerializer;
+import com.usatiuk.objects.iterators.CloseableKvIterator;
+import com.usatiuk.objects.iterators.IteratorStart;
+import com.usatiuk.objects.iterators.MappingKvIterator;
+import com.usatiuk.objects.snapshot.Snapshot;
+import jakarta.enterprise.context.ApplicationScoped;
+import jakarta.inject.Inject;
+import org.apache.commons.lang3.tuple.Pair;
+
+import javax.annotation.Nonnull;
+import java.util.Optional;
+import java.util.function.Consumer;
+
+@ApplicationScoped
+public class SerializingObjectPersistentStore {
+    @Inject
+    ObjectSerializer<JDataVersionedWrapper> serializer;
+
+    @Inject
+    ObjectPersistentStore delegateStore;
+
+    @Nonnull
+    Optional<JDataVersionedWrapper> readObject(JObjectKey name) {
+        return delegateStore.readObject(name).map(serializer::deserialize);
+    }
+
+    public TxManifestRaw prepareManifest(TxManifestObj<? extends JDataVersionedWrapper> names) {
+        return new TxManifestRaw(
+                names.written().stream()
+                        .map(e -> Pair.of(e.getKey(), serializer.serialize(e.getValue())))
+                        .toList()
+                , names.deleted());
+    }
+
+    public Snapshot<JObjectKey, JDataVersionedWrapper> getSnapshot() {
+        return new Snapshot<JObjectKey, JDataVersionedWrapper>() {
+            private final Snapshot<JObjectKey, ByteString> _backing = delegateStore.getSnapshot();
+
+            @Override
+            public CloseableKvIterator<JObjectKey, JDataVersionedWrapper> getIterator(IteratorStart start, JObjectKey key) {
+                return new MappingKvIterator<>(_backing.getIterator(start, key), d -> serializer.deserialize(d));
+            }
+
+            @Nonnull
+            @Override
+            public Optional<JDataVersionedWrapper> readObject(JObjectKey name) {
+                return _backing.readObject(name).map(serializer::deserialize);
+            }
+
+            @Override
+            public long id() {
+                return _backing.id();
+            }
+
+            @Override
+            public void close() {
+                _backing.close();
+            }
+        };
+
+    }
+
+
+//    void commitTx(TxManifestObj<? extends JDataVersionedWrapper> names, Consumer<Runnable> commitLocked) {
+//        delegateStore.commitTx(prepareManifest(names), commitLocked);
+//    }
+
+    void commitTx(TxManifestRaw names, long txId, Consumer<Runnable> commitLocked) {
+        delegateStore.commitTx(names, txId, commitLocked);
+    }
+
+    long getLastCommitId() {
+        return delegateStore.getLastCommitId();
+    }
+}

dhfs-parent/objects/src/main/java/com/usatiuk/objects/stores/TxManifestObj.java

@@ -1,6 +1,6 @@
-package com.usatiuk.dhfs.objects.persistence;
+package com.usatiuk.objects.stores;
 
-import com.usatiuk.dhfs.objects.JObjectKey;
+import com.usatiuk.objects.JObjectKey;
 import org.apache.commons.lang3.tuple.Pair;
 
 import java.io.Serializable;

dhfs-parent/objects/src/main/java/com/usatiuk/objects/stores/TxManifestRaw.java

@@ -1,7 +1,7 @@
-package com.usatiuk.dhfs.objects.persistence;
+package com.usatiuk.objects.stores;
 
 import com.google.protobuf.ByteString;
-import com.usatiuk.dhfs.objects.JObjectKey;
+import com.usatiuk.objects.JObjectKey;
 import org.apache.commons.lang3.tuple.Pair;
 
 import java.io.Serializable;

dhfs-parent/objects/src/main/java/com/usatiuk/objects/stores/WritebackObjectPersistentStore.java

@@ -1,9 +1,13 @@
-package com.usatiuk.dhfs.objects;
+package com.usatiuk.objects.stores;
 
-import com.usatiuk.dhfs.objects.persistence.CachingObjectPersistentStore;
-import com.usatiuk.dhfs.objects.persistence.IteratorStart;
-import com.usatiuk.dhfs.objects.persistence.TxManifestObj;
-import com.usatiuk.dhfs.objects.transaction.TxRecord;
+import com.usatiuk.objects.JDataVersionedWrapper;
+import com.usatiuk.objects.JDataVersionedWrapperImpl;
+import com.usatiuk.objects.JObjectKey;
+import com.usatiuk.objects.iterators.*;
+import com.usatiuk.objects.iterators.*;
+import com.usatiuk.objects.snapshot.Snapshot;
+import com.usatiuk.objects.transaction.TxCommitException;
+import com.usatiuk.objects.transaction.TxRecord;
 import io.quarkus.logging.Log;
 import io.quarkus.runtime.ShutdownEvent;
 import io.quarkus.runtime.StartupEvent;
@@ -303,6 +307,150 @@ public class WritebackObjectPersistentStore {
         }
     }
 
+    public Optional<PendingWriteEntry> getPendingWrite(JObjectKey key) {
+        synchronized (_pendingBundles) {
+            return Optional.ofNullable(_pendingWrites.get().get(key));
+        }
+    }
+
+    @Nonnull
+    public Optional<JDataVersionedWrapper> readObject(JObjectKey name) {
+        var pending = getPendingWrite(name).orElse(null);
+        return switch (pending) {
+            case PendingWrite write -> Optional.of(write.data());
+            case PendingDelete ignored -> Optional.empty();
+            case null -> cachedStore.readObject(name);
+            default -> throw new IllegalStateException("Unexpected value: " + pending);
+        };
+    }
+
+    @Nonnull
+    public VerboseReadResult readObjectVerbose(JObjectKey key) {
+        var pending = getPendingWrite(key).orElse(null);
+        if (pending != null) {
+            return new VerboseReadResultPending(pending);
+        }
+        return new VerboseReadResultPersisted(cachedStore.readObject(key));
+    }
+
+    /**
+     * @param commitLocked - a function that will be called with a Consumer of a new transaction id,
+     *                     that will commit the transaction the changes in the store will be visible to new transactions
+     *                     only after the runnable is called
+     */
+    public Consumer<Runnable> commitTx(Collection<TxRecord.TxObjectRecord<?>> writes, BiConsumer<Long, Runnable> commitLocked) {
+        var bundle = createBundle();
+        long bundleId = bundle.getId();
+        try {
+            for (var action : writes) {
+                switch (action) {
+                    case TxRecord.TxObjectRecordWrite<?> write -> {
+                        Log.trace("Flushing object " + write.key());
+                        bundle.commit(new JDataVersionedWrapperImpl(write.data(), bundleId));
+                    }
+                    case TxRecord.TxObjectRecordDeleted deleted -> {
+                        Log.trace("Deleting object " + deleted.key());
+                        bundle.delete(deleted.key());
+                    }
+                    default -> {
+                        throw new TxCommitException("Unexpected value: " + action.key());
+                    }
+                }
+            }
+        } catch (Throwable t) {
+            dropBundle(bundle);
+            throw new TxCommitException(t.getMessage(), t);
+        }
+
+
+        Log.tracef("Committing transaction %d to storage", bundleId);
+        commitLocked.accept(bundleId, () -> {
+            commitBundle(bundle);
+        });
+
+        return r -> asyncFence(bundleId, r);
+    }
+
+    public Snapshot<JObjectKey, JDataVersionedWrapper> getSnapshot() {
+        PSortedMap<JObjectKey, PendingWriteEntry> pendingWrites;
+        Snapshot<JObjectKey, JDataVersionedWrapper> cache = null;
+        long lastTxId;
+
+        try {
+            _pendingWritesVersionLock.readLock().lock();
+            try {
+                pendingWrites = _pendingWrites.get();
+                cache = cachedStore.getSnapshot();
+                lastTxId = getLastTxId();
+            } finally {
+                _pendingWritesVersionLock.readLock().unlock();
+            }
+
+            Snapshot<JObjectKey, JDataVersionedWrapper> finalCache = cache;
+            return new Snapshot<JObjectKey, JDataVersionedWrapper>() {
+                private final PSortedMap<JObjectKey, PendingWriteEntry> _pendingWrites = pendingWrites;
+                private final Snapshot<JObjectKey, JDataVersionedWrapper> _cache = finalCache;
+                private final long txId = lastTxId;
+
+                @Override
+                public CloseableKvIterator<JObjectKey, JDataVersionedWrapper> getIterator(IteratorStart start, JObjectKey key) {
+                    return new TombstoneMergingKvIterator<>("writeback-ps", start, key,
+                            (tS, tK) -> new MappingKvIterator<>(
+                                    new NavigableMapKvIterator<>(_pendingWrites, tS, tK),
+                                    e -> switch (e) {
+                                        case PendingWrite pw -> new Data<>(pw.data());
+                                        case PendingDelete d -> new Tombstone<>();
+                                        default -> throw new IllegalStateException("Unexpected value: " + e);
+                                    }),
+                            (tS, tK) -> new MappingKvIterator<>(_cache.getIterator(tS, tK), Data::new));
+                }
+
+                @Nonnull
+                @Override
+                public Optional<JDataVersionedWrapper> readObject(JObjectKey name) {
+                    var cached = _pendingWrites.get(name);
+                    if (cached != null) {
+                        return switch (cached) {
+                            case PendingWrite c -> Optional.of(c.data());
+                            case PendingDelete d -> {
+                                yield Optional.empty();
+                            }
+                            default -> throw new IllegalStateException("Unexpected value: " + cached);
+                        };
+                    }
+                    return _cache.readObject(name);
+                }
+
+                @Override
+                public long id() {
+                    assert lastTxId >= _cache.id();
+                    return lastTxId;
+                }
+
+                @Override
+                public void close() {
+                    _cache.close();
+                }
+            };
+        } catch (Throwable e) {
+            if (cache != null)
+                cache.close();
+            throw e;
+        }
+    }
+
+    public long getLastTxId() {
+        _pendingWritesVersionLock.readLock().lock();
+        try {
+            return _lastCommittedTx.get();
+        } finally {
+            _pendingWritesVersionLock.readLock().unlock();
+        }
+    }
+
+    public interface VerboseReadResult {
+    }
+
     private static class TxBundle {
         private final LinkedHashMap<JObjectKey, BundleEntry> _entries = new LinkedHashMap<>();
         private final ArrayList<Runnable> _callbacks = new ArrayList<>();
@@ -384,107 +532,9 @@ public class WritebackObjectPersistentStore {
         }
     }
 
-    public Optional<PendingWriteEntry> getPendingWrite(JObjectKey key) {
-        synchronized (_pendingBundles) {
-            return Optional.ofNullable(_pendingWrites.get().get(key));
-        }
-    }
-
-    @Nonnull
-    public Optional<JDataVersionedWrapper> readObject(JObjectKey name) {
-        var pending = getPendingWrite(name).orElse(null);
-        return switch (pending) {
-            case PendingWrite write -> Optional.of(write.data());
-            case PendingDelete ignored -> Optional.empty();
-            case null -> cachedStore.readObject(name);
-            default -> throw new IllegalStateException("Unexpected value: " + pending);
-        };
-    }
-
-    public interface VerboseReadResult {
-    }
-
     public record VerboseReadResultPersisted(Optional<JDataVersionedWrapper> data) implements VerboseReadResult {
     }
 
     public record VerboseReadResultPending(PendingWriteEntry pending) implements VerboseReadResult {
     }
-
-    @Nonnull
-    public VerboseReadResult readObjectVerbose(JObjectKey key) {
-        var pending = getPendingWrite(key).orElse(null);
-        if (pending != null) {
-            return new VerboseReadResultPending(pending);
-        }
-        return new VerboseReadResultPersisted(cachedStore.readObject(key));
-    }
-
-    /**
-     * @param commitLocked - a function that will be called with a Consumer of a new transaction id,
-     *                     that will commit the transaction the changes in the store will be visible to new transactions
-     *                     only after the runnable is called
-     */
-    public Consumer<Runnable> commitTx(Collection<TxRecord.TxObjectRecord<?>> writes, BiConsumer<Long, Runnable> commitLocked) {
-        var bundle = createBundle();
-        long bundleId = bundle.getId();
-        try {
-            for (var action : writes) {
-                switch (action) {
-                    case TxRecord.TxObjectRecordWrite<?> write -> {
-                        Log.trace("Flushing object " + write.key());
-                        bundle.commit(new JDataVersionedWrapperImpl(write.data(), bundleId));
-                    }
-                    case TxRecord.TxObjectRecordDeleted deleted -> {
-                        Log.trace("Deleting object " + deleted.key());
-                        bundle.delete(deleted.key());
-                    }
-                    default -> {
-                        throw new TxCommitException("Unexpected value: " + action.key());
-                    }
-                }
-            }
-        } catch (Throwable t) {
-            dropBundle(bundle);
-            throw new TxCommitException(t.getMessage(), t);
-        }
-
-
-        Log.tracef("Committing transaction %d to storage", bundleId);
-        commitLocked.accept(bundleId, () -> {
-            commitBundle(bundle);
-        });
-
-        return r -> asyncFence(bundleId, r);
-    }
-
-    // Returns an iterator with a view of all commited objects
-    // Does not have to guarantee consistent view, snapshots are handled by upper layers
-    // Invalidated by commitBundle, but might return data after it has been really committed
-    public CloseableKvIterator<JObjectKey, JDataVersionedWrapper> getIterator(IteratorStart start, JObjectKey key) {
-        Log.tracev("Getting writeback iterator: {0}, {1}", start, key);
-        _pendingWritesVersionLock.readLock().lock();
-        try {
-            var curPending = _pendingWrites.get();
-            return new TombstoneMergingKvIterator<>("writeback-ps", start, key,
-                    (tS, tK) -> new MappingKvIterator<>(
-                            new NavigableMapKvIterator<>(curPending, tS, tK),
-                            e -> switch (e) {
-                                case PendingWrite pw -> new Data<>(pw.data());
-                                case PendingDelete d -> new Tombstone<>();
-                                default -> throw new IllegalStateException("Unexpected value: " + e);
-                            }),
-                    (tS, tK) -> cachedStore.getIterator(tS, tK));
-        } finally {
-            _pendingWritesVersionLock.readLock().unlock();
-        }
-    }
-
-    public long getLastTxId() {
-        _pendingWritesVersionLock.readLock().lock();
-        try {
-            return _lastCommittedTx.get();
-        } finally {
-            _pendingWritesVersionLock.readLock().unlock();
-        }
-    }
 }

dhfs-parent/objects/src/main/java/com/usatiuk/objects/transaction/CurrentTransaction.java

@@ -1,15 +1,12 @@
-package com.usatiuk.dhfs.objects;
+package com.usatiuk.objects.transaction;
 
-import com.usatiuk.dhfs.objects.persistence.IteratorStart;
-import com.usatiuk.dhfs.objects.transaction.LockingStrategy;
-import com.usatiuk.dhfs.objects.transaction.Transaction;
+import com.usatiuk.objects.JData;
+import com.usatiuk.objects.JObjectKey;
+import com.usatiuk.objects.iterators.CloseableKvIterator;
+import com.usatiuk.objects.iterators.IteratorStart;
 import jakarta.enterprise.context.ApplicationScoped;
 import jakarta.inject.Inject;
-import org.apache.commons.lang3.tuple.Pair;
 
-import javax.annotation.Nonnull;
-import java.util.Collection;
-import java.util.Iterator;
 import java.util.Optional;
 
 @ApplicationScoped
@@ -37,12 +34,6 @@ public class CurrentTransaction implements Transaction {
         transactionManager.current().delete(key);
     }
 
-    @Nonnull
-    @Override
-    public Collection<JObjectKey> findAllObjects() {
-        return transactionManager.current().findAllObjects();
-    }
-
     @Override
     public CloseableKvIterator<JObjectKey, JData> getIterator(IteratorStart start, JObjectKey key) {
         return transactionManager.current().getIterator(start, key);

dhfs-parent/objects/src/main/java/com/usatiuk/objects/transaction/JObjectManager.java

@@ -1,7 +1,9 @@
-package com.usatiuk.dhfs.objects;
+package com.usatiuk.objects.transaction;
 
-import com.usatiuk.dhfs.objects.snapshot.SnapshotManager;
-import com.usatiuk.dhfs.objects.transaction.*;
+import com.usatiuk.objects.JData;
+import com.usatiuk.objects.JDataVersionedWrapper;
+import com.usatiuk.objects.JObjectKey;
+import com.usatiuk.objects.snapshot.SnapshotManager;
 import com.usatiuk.dhfs.utils.AutoCloseableNoThrow;
 import io.quarkus.logging.Log;
 import io.quarkus.runtime.StartupEvent;
@@ -10,26 +12,32 @@ import jakarta.enterprise.context.ApplicationScoped;
 import jakarta.enterprise.event.Observes;
 import jakarta.enterprise.inject.Instance;
 import jakarta.inject.Inject;
+import org.apache.commons.lang3.tuple.Pair;
 
 import java.util.*;
 import java.util.function.Consumer;
 import java.util.function.Function;
 import java.util.stream.Stream;
 
-// Manages all access to com.usatiuk.dhfs.objects.JData objects.
+// Manages all access to com.usatiuk.objects.JData objects.
 // In particular, it serves as a source of truth for what is committed to the backing storage.
 // All data goes through it, it is responsible for transaction atomicity
 // TODO: persistent tx id
 @ApplicationScoped
 public class JObjectManager {
     private final List<PreCommitTxHook> _preCommitTxHooks;
-    private boolean _ready = false;
     @Inject
     SnapshotManager snapshotManager;
     @Inject
     TransactionFactory transactionFactory;
     @Inject
     LockManager lockManager;
+    private boolean _ready = false;
+
+    JObjectManager(Instance<PreCommitTxHook> preCommitTxHooks) {
+        _preCommitTxHooks = List.copyOf(preCommitTxHooks.stream().sorted(Comparator.comparingInt(PreCommitTxHook::getPriority)).toList());
+        Log.debugv("Pre-commit hooks: {0}", String.join("->", _preCommitTxHooks.stream().map(Objects::toString).toList()));
+    }
 
     private void verifyReady() {
         if (!_ready) throw new IllegalStateException("Wrong service order!");
@@ -39,10 +47,6 @@ public class JObjectManager {
         _ready = true;
     }
 
-    JObjectManager(Instance<PreCommitTxHook> preCommitTxHooks) {
-        _preCommitTxHooks = preCommitTxHooks.stream().sorted(Comparator.comparingInt(PreCommitTxHook::getPriority)).toList();
-    }
-
     public TransactionPrivate createTransaction() {
         verifyReady();
         var tx = transactionFactory.createTransaction();
@@ -50,7 +54,7 @@ public class JObjectManager {
         return tx;
     }
 
-    public TransactionHandle commit(TransactionPrivate tx) {
+    public Pair<Collection<Runnable>, TransactionHandle> commit(TransactionPrivate tx) {
         verifyReady();
         var writes = new LinkedHashMap<JObjectKey, TxRecord.TxObjectRecord<?>>();
         var dependenciesLocked = new LinkedHashMap<JObjectKey, Optional<JDataVersionedWrapper>>();
@@ -66,34 +70,51 @@ public class JObjectManager {
                     });
                 };
 
-        // For existing objects:
-        // Check that their version is not higher than the version of transaction being committed
-        // TODO: check deletions, inserts
         try {
             try {
-                Function<JObjectKey, JData> getPrev =
-                        key -> switch (writes.get(key)) {
-                            case TxRecord.TxObjectRecordWrite<?> write -> write.data();
-                            case TxRecord.TxObjectRecordDeleted deleted -> null;
-                            case null -> tx.getFromSource(JData.class, key).orElse(null);
-                            default -> {
-                                throw new TxCommitException("Unexpected value: " + writes.get(key));
-                            }
-                        };
+                long pendingCount = 0;
+                Map<PreCommitTxHook, Map<JObjectKey, TxRecord.TxObjectRecord<?>>> pendingWrites = Map.ofEntries(
+                        _preCommitTxHooks.stream().map(p -> Pair.of(p, new HashMap<>())).toArray(Pair[]::new)
+                );
+                Map<PreCommitTxHook, Map<JObjectKey, TxRecord.TxObjectRecord<?>>> lastWrites = Map.ofEntries(
+                        _preCommitTxHooks.stream().map(p -> Pair.of(p, new HashMap<>())).toArray(Pair[]::new)
+                );
 
-                boolean somethingChanged;
+                for (var n : tx.drainNewWrites()) {
+                    for (var hookPut : _preCommitTxHooks) {
+                        pendingWrites.get(hookPut).put(n.key(), n);
+                        pendingCount++;
+                    }
+                    writes.put(n.key(), n);
+                }
+
+                // Run hooks for all objects
+                // Every hook should see every change made to every object, yet the object's evolution
+                // should be consistent from the view point of each individual hook
+                // For example, when a hook makes changes to an object, and another hook changes the object before/after it
+                // on the next iteration, the first hook should receive the version of the object it had created
+                // as the "old" version, and the new version with all the changes after it.
                 do {
-                    somethingChanged = false;
-                    Map<JObjectKey, TxRecord.TxObjectRecord<?>> currentIteration = new HashMap();
                     for (var hook : _preCommitTxHooks) {
-                        for (var n : tx.drainNewWrites())
-                            currentIteration.put(n.key(), n);
-                        Log.trace("Commit iteration with " + currentIteration.size() + " records for hook " + hook.getClass());
+                        var lastCurHookSeen = lastWrites.get(hook);
+                        Function<JObjectKey, JData> getPrev =
+                                key -> switch (lastCurHookSeen.get(key)) {
+                                    case TxRecord.TxObjectRecordWrite<?> write -> write.data();
+                                    case TxRecord.TxObjectRecordDeleted deleted -> null;
+                                    case null -> tx.getFromSource(JData.class, key).orElse(null);
+                                    default -> {
+                                        throw new TxCommitException("Unexpected value: " + writes.get(key));
+                                    }
+                                };
 
-                        for (var entry : currentIteration.entrySet()) {
-                            somethingChanged = true;
-                            Log.trace("Running pre-commit hook " + hook.getClass() + " for" + entry.getKey());
+                        var curIteration = pendingWrites.get(hook);
+
+//                        Log.trace("Commit iteration with " + curIteration.size() + " records for hook " + hook.getClass());
+
+                        for (var entry : curIteration.entrySet()) {
+//                            Log.trace("Running pre-commit hook " + hook.getClass() + " for" + entry.getKey());
                             var oldObj = getPrev.apply(entry.getKey());
+                            lastCurHookSeen.put(entry.getKey(), entry.getValue());
                             switch (entry.getValue()) {
                                 case TxRecord.TxObjectRecordWrite<?> write -> {
                                     if (oldObj == null) {
@@ -108,32 +129,61 @@ public class JObjectManager {
                                 default -> throw new TxCommitException("Unexpected value: " + entry);
                             }
                         }
-                    }
-                    writes.putAll(currentIteration);
-                } while (somethingChanged);
 
-                if (writes.isEmpty()) {
-                    Log.trace("Committing transaction - no changes");
-                    return new TransactionHandle() {
-                        @Override
-                        public void onFlush(Runnable runnable) {
-                            runnable.run();
+                        pendingCount -= curIteration.size();
+                        curIteration.clear();
+
+                        for (var n : tx.drainNewWrites()) {
+                            for (var hookPut : _preCommitTxHooks) {
+                                if (hookPut == hook) {
+                                    lastCurHookSeen.put(n.key(), n);
+                                    continue;
+                                }
+                                var before = pendingWrites.get(hookPut).put(n.key(), n);
+                                if (before == null)
+                                    pendingCount++;
+                            }
+                            writes.put(n.key(), n);
                         }
-                    };
-                }
-
-            } finally {
-                readSet = tx.reads();
-
-                Stream.concat(readSet.keySet().stream(), writes.keySet().stream())
-                        .sorted(Comparator.comparing(JObjectKey::toString))
-                        .forEach(addDependency);
-
-                for (var read : readSet.entrySet()) {
+                    }
+                } while (pendingCount > 0);
+            } catch (Throwable e) {
+                for (var read : tx.reads().entrySet()) {
                     if (read.getValue() instanceof TransactionObjectLocked<?> locked) {
                         toUnlock.add(locked.lock());
                     }
                 }
+                throw e;
+            }
+
+            readSet = tx.reads();
+
+            if (!writes.isEmpty()) {
+                Stream.concat(readSet.keySet().stream(), writes.keySet().stream())
+                        .sorted(Comparator.comparing(JObjectKey::toString))
+                        .forEach(addDependency);
+            }
+
+            for (var read : readSet.entrySet()) {
+                if (read.getValue() instanceof TransactionObjectLocked<?> locked) {
+                    toUnlock.add(locked.lock());
+                }
+            }
+
+            if (writes.isEmpty()) {
+                Log.trace("Committing transaction - no changes");
+
+                return Pair.of(
+                        Stream.concat(
+                                tx.getOnCommit().stream(),
+                                tx.getOnFlush().stream()
+                        ).toList(),
+                        new TransactionHandle() {
+                            @Override
+                            public void onFlush(Runnable runnable) {
+                                runnable.run();
+                            }
+                        });
             }
 
             Log.trace("Committing transaction start");
@@ -175,20 +225,18 @@ public class JObjectManager {
                                 return true;
                             }).toList());
 
-            for (var callback : tx.getOnCommit()) {
-                callback.run();
-            }
-
             for (var callback : tx.getOnFlush()) {
                 addFlushCallback.accept(callback);
             }
 
-            return new TransactionHandle() {
-                @Override
-                public void onFlush(Runnable runnable) {
-                    addFlushCallback.accept(runnable);
-                }
-            };
+            return Pair.of(
+                    List.copyOf(tx.getOnCommit()),
+                    new TransactionHandle() {
+                        @Override
+                        public void onFlush(Runnable runnable) {
+                            addFlushCallback.accept(runnable);
+                        }
+                    });
         } catch (Throwable t) {
             Log.trace("Error when committing transaction", t);
             throw new TxCommitException(t.getMessage(), t);

dhfs-parent/objects/src/main/java/com/usatiuk/objects/transaction/LockManager.java

@@ -1,14 +1,23 @@
-package com.usatiuk.dhfs.objects;
+package com.usatiuk.objects.transaction;
 
+import com.usatiuk.objects.JObjectKey;
 import com.usatiuk.dhfs.utils.AutoCloseableNoThrow;
 import com.usatiuk.dhfs.utils.DataLocker;
+import jakarta.annotation.Nonnull;
+import jakarta.annotation.Nullable;
 import jakarta.enterprise.context.ApplicationScoped;
 
 @ApplicationScoped
 public class LockManager {
     private final DataLocker _objLocker = new DataLocker();
 
+    @Nonnull
     public AutoCloseableNoThrow lockObject(JObjectKey key) {
         return _objLocker.lock(key);
     }
+
+    @Nullable
+    public AutoCloseableNoThrow tryLockObject(JObjectKey key) {
+        return _objLocker.tryLock(key);
+    }
 }

dhfs-parent/objects/src/main/java/com/usatiuk/objects/transaction/LockingStrategy.java

@@ -1,4 +1,4 @@
-package com.usatiuk.dhfs.objects.transaction;
+package com.usatiuk.objects.transaction;
 
 public enum LockingStrategy {
     OPTIMISTIC,           // Optimistic write, no blocking other possible writers/readers

dhfs-parent/objects/src/main/java/com/usatiuk/objects/transaction/PreCommitTxHook.java

@@ -1,4 +1,7 @@
-package com.usatiuk.dhfs.objects;
+package com.usatiuk.objects.transaction;
+
+import com.usatiuk.objects.JData;
+import com.usatiuk.objects.JObjectKey;
 
 public interface PreCommitTxHook {
     default void onChange(JObjectKey key, JData old, JData cur) {

dhfs-parent/objects/src/main/java/com/usatiuk/objects/transaction/Transaction.java

@@ -1,12 +1,10 @@
-package com.usatiuk.dhfs.objects.transaction;
+package com.usatiuk.objects.transaction;
 
-import com.usatiuk.dhfs.objects.CloseableKvIterator;
-import com.usatiuk.dhfs.objects.JData;
-import com.usatiuk.dhfs.objects.JObjectKey;
-import com.usatiuk.dhfs.objects.persistence.IteratorStart;
+import com.usatiuk.objects.JData;
+import com.usatiuk.objects.JObjectKey;
+import com.usatiuk.objects.iterators.CloseableKvIterator;
+import com.usatiuk.objects.iterators.IteratorStart;
 
-import javax.annotation.Nonnull;
-import java.util.Collection;
 import java.util.Optional;
 
 // The transaction interface actually used by user code to retrieve objects
@@ -19,9 +17,6 @@ public interface Transaction extends TransactionHandle {
 
     void delete(JObjectKey key);
 
-    @Nonnull
-    Collection<JObjectKey> findAllObjects(); // FIXME: This is crap
-
     default <T extends JData> Optional<T> get(Class<T> type, JObjectKey key) {
         return get(type, key, LockingStrategy.OPTIMISTIC);
     }

dhfs-parent/objects/src/main/java/com/usatiuk/objects/transaction/TransactionFactory.java

@@ -1,4 +1,4 @@
-package com.usatiuk.dhfs.objects.transaction;
+package com.usatiuk.objects.transaction;
 
 public interface TransactionFactory {
     TransactionPrivate createTransaction();

dhfs-parent/objects/src/main/java/com/usatiuk/objects/transaction/TransactionFactoryImpl.java

@@ -1,14 +1,17 @@
-package com.usatiuk.dhfs.objects.transaction;
+package com.usatiuk.objects.transaction;
 
-import com.usatiuk.dhfs.objects.*;
-import com.usatiuk.dhfs.objects.persistence.IteratorStart;
-import com.usatiuk.dhfs.objects.snapshot.SnapshotManager;
+import com.usatiuk.objects.JData;
+import com.usatiuk.objects.JDataVersionedWrapper;
+import com.usatiuk.objects.JObjectKey;
+import com.usatiuk.objects.iterators.*;
+import com.usatiuk.objects.snapshot.Snapshot;
+import com.usatiuk.objects.snapshot.SnapshotManager;
 import io.quarkus.logging.Log;
 import jakarta.enterprise.context.ApplicationScoped;
 import jakarta.inject.Inject;
 import org.apache.commons.lang3.tuple.Pair;
+import org.eclipse.microprofile.config.inject.ConfigProperty;
 
-import javax.annotation.Nonnull;
 import java.util.*;
 
 @ApplicationScoped
@@ -17,6 +20,8 @@ public class TransactionFactoryImpl implements TransactionFactory {
     SnapshotManager snapshotManager;
     @Inject
     LockManager lockManager;
+    @ConfigProperty(name = "dhfs.objects.transaction.never-lock")
+    boolean neverLock;
 
     @Override
     public TransactionPrivate createTransaction() {
@@ -52,16 +57,147 @@ public class TransactionFactoryImpl implements TransactionFactory {
     private class TransactionImpl implements TransactionPrivate {
         private final Map<JObjectKey, TransactionObject<?>> _readSet = new HashMap<>();
         private final NavigableMap<JObjectKey, TxRecord.TxObjectRecord<?>> _writes = new TreeMap<>();
-
-        private Map<JObjectKey, TxRecord.TxObjectRecord<?>> _newWrites = new HashMap<>();
         private final List<Runnable> _onCommit = new ArrayList<>();
         private final List<Runnable> _onFlush = new ArrayList<>();
-        private final SnapshotManager.Snapshot _snapshot;
+        private final Snapshot<JObjectKey, JDataVersionedWrapper> _snapshot;
+        private boolean _closed = false;
+        private Map<JObjectKey, TxRecord.TxObjectRecord<?>> _newWrites = new HashMap<>();
 
         private TransactionImpl() {
             _snapshot = snapshotManager.createSnapshot();
         }
 
+        @Override
+        public void onCommit(Runnable runnable) {
+            _onCommit.add(runnable);
+        }
+
+        @Override
+        public void onFlush(Runnable runnable) {
+            _onFlush.add(runnable);
+        }
+
+        @Override
+        public Collection<Runnable> getOnCommit() {
+            return Collections.unmodifiableCollection(_onCommit);
+        }
+
+        @Override
+        public Snapshot<JObjectKey, JDataVersionedWrapper> snapshot() {
+            return _snapshot;
+        }
+
+        @Override
+        public Collection<Runnable> getOnFlush() {
+            return Collections.unmodifiableCollection(_onFlush);
+        }
+
+        @Override
+        public <T extends JData> Optional<T> getFromSource(Class<T> type, JObjectKey key) {
+            var got = _readSet.get(key);
+
+            if (got == null) {
+                var read = _snapshot.readObject(key);
+                _readSet.put(key, new TransactionObjectNoLock<>(read));
+                return read.map(JDataVersionedWrapper::data).map(type::cast);
+            }
+
+            return got.data().map(JDataVersionedWrapper::data).map(type::cast);
+        }
+
+        public <T extends JData> Optional<T> getWriteLockedFromSource(Class<T> type, JObjectKey key) {
+            var got = _readSet.get(key);
+
+            if (got == null) {
+                var lock = lockManager.lockObject(key);
+                try {
+                    var read = _snapshot.readObject(key);
+                    _readSet.put(key, new TransactionObjectLocked<>(read, lock));
+                    return read.map(JDataVersionedWrapper::data).map(type::cast);
+                } catch (Exception e) {
+                    lock.close();
+                    throw e;
+                }
+            }
+
+            return got.data().map(JDataVersionedWrapper::data).map(type::cast);
+        }
+
+        @Override
+        public <T extends JData> Optional<T> get(Class<T> type, JObjectKey key, LockingStrategy strategy) {
+            switch (_writes.get(key)) {
+                case TxRecord.TxObjectRecordWrite<?> write -> {
+                    return Optional.of(type.cast(write.data()));
+                }
+                case TxRecord.TxObjectRecordDeleted deleted -> {
+                    return Optional.empty();
+                }
+                case null, default -> {
+                }
+            }
+
+            if (neverLock)
+                return getFromSource(type, key);
+
+            return switch (strategy) {
+                case OPTIMISTIC -> getFromSource(type, key);
+                case WRITE -> getWriteLockedFromSource(type, key);
+            };
+        }
+
+        @Override
+        public void delete(JObjectKey key) {
+            var got = _writes.get(key);
+            if (got != null) {
+                if (got instanceof TxRecord.TxObjectRecordDeleted) {
+                    return;
+                }
+            }
+
+            _writes.put(key, new TxRecord.TxObjectRecordDeleted(key));
+            _newWrites.put(key, new TxRecord.TxObjectRecordDeleted(key));
+        }
+
+        @Override
+        public CloseableKvIterator<JObjectKey, JData> getIterator(IteratorStart start, JObjectKey key) {
+            Log.tracev("Getting tx iterator with start={0}, key={1}", start, key);
+            return new ReadTrackingIterator(new TombstoneMergingKvIterator<>("tx", start, key,
+                    (tS, tK) -> new MappingKvIterator<>(new NavigableMapKvIterator<>(_writes, tS, tK),
+                            t -> switch (t) {
+                                case TxRecord.TxObjectRecordWrite<?> write ->
+                                        new Data<>(new ReadTrackingInternalCrapTx(write.data()));
+                                case TxRecord.TxObjectRecordDeleted deleted -> new Tombstone<>();
+                                case null, default -> null;
+                            }),
+                    (tS, tK) -> new MappingKvIterator<>(_snapshot.getIterator(tS, tK),
+                            d -> new Data<ReadTrackingInternalCrap>(new ReadTrackingInternalCrapSource(d)))));
+        }
+
+        @Override
+        public void put(JData obj) {
+            _writes.put(obj.key(), new TxRecord.TxObjectRecordWrite<>(obj));
+            _newWrites.put(obj.key(), new TxRecord.TxObjectRecordWrite<>(obj));
+        }
+
+        @Override
+        public Collection<TxRecord.TxObjectRecord<?>> drainNewWrites() {
+            var ret = _newWrites;
+            _newWrites = new HashMap<>();
+            return ret.values();
+        }
+
+        @Override
+        public Map<JObjectKey, TransactionObject<?>> reads() {
+            return Collections.unmodifiableMap(_readSet);
+        }
+
+        @Override
+        public void close() {
+            if (_closed) return;
+            _closed = true;
+            _snapshot.close();
+        }
+
         private class ReadTrackingIterator implements CloseableKvIterator<JObjectKey, JData> {
             private final CloseableKvIterator<JObjectKey, ReadTrackingInternalCrap> _backing;
 
@@ -122,138 +258,5 @@ public class TransactionFactoryImpl implements TransactionFactory {
                 return Pair.of(got.getKey(), got.getValue().obj());
             }
         }
-
-        @Override
-        public void onCommit(Runnable runnable) {
-            _onCommit.add(runnable);
-        }
-
-        @Override
-        public void onFlush(Runnable runnable) {
-            _onFlush.add(runnable);
-        }
-
-        @Override
-        public Collection<Runnable> getOnCommit() {
-            return Collections.unmodifiableCollection(_onCommit);
-        }
-
-        @Override
-        public SnapshotManager.Snapshot snapshot() {
-            return _snapshot;
-        }
-
-        @Override
-        public Collection<Runnable> getOnFlush() {
-            return Collections.unmodifiableCollection(_onFlush);
-        }
-
-        @Override
-        public <T extends JData> Optional<T> getFromSource(Class<T> type, JObjectKey key) {
-            var got = _readSet.get(key);
-
-            if (got == null) {
-                var read = _snapshot.readObject(key);
-                _readSet.put(key, new TransactionObjectNoLock<>(read));
-                return read.map(JDataVersionedWrapper::data).map(type::cast);
-            }
-
-            return got.data().map(JDataVersionedWrapper::data).map(type::cast);
-        }
-
-        public <T extends JData> Optional<T> getWriteLockedFromSource(Class<T> type, JObjectKey key) {
-            var got = _readSet.get(key);
-
-            if (got == null) {
-                var lock = lockManager.lockObject(key);
-                try {
-                    var read = _snapshot.readObject(key);
-                    _readSet.put(key, new TransactionObjectLocked<>(read, lock));
-                    return read.map(JDataVersionedWrapper::data).map(type::cast);
-                } catch (Exception e) {
-                    lock.close();
-                    throw e;
-                }
-            }
-
-            return got.data().map(JDataVersionedWrapper::data).map(type::cast);
-        }
-
-        @Override
-        public <T extends JData> Optional<T> get(Class<T> type, JObjectKey key, LockingStrategy strategy) {
-            switch (_writes.get(key)) {
-                case TxRecord.TxObjectRecordWrite<?> write -> {
-                    return Optional.of(type.cast(write.data()));
-                }
-                case TxRecord.TxObjectRecordDeleted deleted -> {
-                    return Optional.empty();
-                }
-                case null, default -> {
-                }
-            }
-
-            return switch (strategy) {
-                case OPTIMISTIC -> getFromSource(type, key);
-                case WRITE -> getWriteLockedFromSource(type, key);
-            };
-        }
-
-        @Override
-        public void delete(JObjectKey key) {
-            var got = _writes.get(key);
-            if (got != null) {
-                if (got instanceof TxRecord.TxObjectRecordDeleted) {
-                    return;
-                }
-            }
-
-            _writes.put(key, new TxRecord.TxObjectRecordDeleted(key));
-            _newWrites.put(key, new TxRecord.TxObjectRecordDeleted(key));
-        }
-
-        @Nonnull
-        @Override
-        public Collection<JObjectKey> findAllObjects() {
-//            return store.findAllObjects();
-            return List.of();
-        }
-
-        @Override
-        public CloseableKvIterator<JObjectKey, JData> getIterator(IteratorStart start, JObjectKey key) {
-            Log.tracev("Getting tx iterator with start={0}, key={1}", start, key);
-            return new ReadTrackingIterator(new TombstoneMergingKvIterator<>("tx", start, key,
-                    (tS, tK) -> new MappingKvIterator<>(new NavigableMapKvIterator<>(_writes, tS, tK),
-                            t -> switch (t) {
-                                case TxRecord.TxObjectRecordWrite<?> write ->
-                                        new Data<>(new ReadTrackingInternalCrapTx(write.data()));
-                                case TxRecord.TxObjectRecordDeleted deleted -> new Tombstone<>();
-                                case null, default -> null;
-                            }),
-                    (tS, tK) -> new MappingKvIterator<>(_snapshot.getIterator(tS, tK),
-                            d -> new Data<ReadTrackingInternalCrap>(new ReadTrackingInternalCrapSource(d)))));
-        }
-
-        @Override
-        public void put(JData obj) {
-            _writes.put(obj.key(), new TxRecord.TxObjectRecordWrite<>(obj));
-            _newWrites.put(obj.key(), new TxRecord.TxObjectRecordWrite<>(obj));
-        }
-
-        @Override
-        public Collection<TxRecord.TxObjectRecord<?>> drainNewWrites() {
-            var ret = _newWrites;
-            _newWrites = new HashMap<>();
-            return ret.values();
-        }
-
-        @Override
-        public Map<JObjectKey, TransactionObject<?>> reads() {
-            return Collections.unmodifiableMap(_readSet);
-        }
-
-        @Override
-        public void close() {
-            _snapshot.close();
-        }
     }
 }

dhfs-parent/objects/src/main/java/com/usatiuk/objects/transaction/TransactionHandle.java

@@ -1,4 +1,4 @@
-package com.usatiuk.dhfs.objects.transaction;
+package com.usatiuk.objects.transaction;
 
 public interface TransactionHandle {
     void onFlush(Runnable runnable);

dhfs-parent/objects/src/main/java/com/usatiuk/objects/transaction/TransactionHandlePrivate.java

@@ -1,4 +1,4 @@
-package com.usatiuk.dhfs.objects.transaction;
+package com.usatiuk.objects.transaction;
 
 import java.util.Collection;
 

dhfs-parent/objects/src/main/java/com/usatiuk/objects/transaction/TransactionManager.java

@@ -1,7 +1,5 @@
-package com.usatiuk.dhfs.objects;
+package com.usatiuk.objects.transaction;
 
-import com.usatiuk.dhfs.objects.transaction.Transaction;
-import com.usatiuk.dhfs.objects.transaction.TransactionHandle;
 import com.usatiuk.dhfs.utils.VoidFn;
 import io.quarkus.logging.Log;
 

dhfs-parent/objects/src/main/java/com/usatiuk/objects/transaction/TransactionManagerImpl.java

@@ -1,11 +1,11 @@
-package com.usatiuk.dhfs.objects;
+package com.usatiuk.objects.transaction;
 
-import com.usatiuk.dhfs.objects.transaction.Transaction;
-import com.usatiuk.dhfs.objects.transaction.TransactionHandle;
-import com.usatiuk.dhfs.objects.transaction.TransactionPrivate;
 import io.quarkus.logging.Log;
 import jakarta.enterprise.context.ApplicationScoped;
 import jakarta.inject.Inject;
+import org.apache.commons.lang3.tuple.Pair;
+
+import java.util.Collection;
 
 @ApplicationScoped
 public class TransactionManagerImpl implements TransactionManager {
@@ -31,8 +31,10 @@ public class TransactionManagerImpl implements TransactionManager {
         }
 
         Log.trace("Committing transaction");
+
+        Pair<Collection<Runnable>, TransactionHandle> ret;
         try {
-            return jObjectManager.commit(_currentTransaction.get());
+            ret = jObjectManager.commit(_currentTransaction.get());
         } catch (Throwable e) {
             Log.trace("Transaction commit failed", e);
             throw e;
@@ -40,6 +42,15 @@ public class TransactionManagerImpl implements TransactionManager {
             _currentTransaction.get().close();
             _currentTransaction.remove();
         }
+
+        for (var r : ret.getLeft()) {
+            try {
+                r.run();
+            } catch (Throwable e) {
+                Log.error("Transaction commit hook error: ", e);
+            }
+        }
+        return ret.getRight();
     }
 
     @Override

dhfs-parent/objects/src/main/java/com/usatiuk/objects/transaction/TransactionObject.java

@@ -0,0 +1,10 @@
+package com.usatiuk.objects.transaction;
+
+import com.usatiuk.objects.JData;
+import com.usatiuk.objects.JDataVersionedWrapper;
+
+import java.util.Optional;
+
+public interface TransactionObject<T extends JData> {
+    Optional<JDataVersionedWrapper> data();
+}

dhfs-parent/objects/src/main/java/com/usatiuk/objects/transaction/TransactionObjectLocked.java

@@ -1,6 +1,7 @@
-package com.usatiuk.dhfs.objects;
+package com.usatiuk.objects.transaction;
 
-import com.usatiuk.dhfs.objects.transaction.TransactionObject;
+import com.usatiuk.objects.JData;
+import com.usatiuk.objects.JDataVersionedWrapper;
 import com.usatiuk.dhfs.utils.AutoCloseableNoThrow;
 
 import java.util.Optional;

dhfs-parent/objects/src/main/java/com/usatiuk/objects/transaction/TransactionObjectNoLock.java

@@ -1,6 +1,7 @@
-package com.usatiuk.dhfs.objects;
+package com.usatiuk.objects.transaction;
 
-import com.usatiuk.dhfs.objects.transaction.TransactionObject;
+import com.usatiuk.objects.JData;
+import com.usatiuk.objects.JDataVersionedWrapper;
 
 import java.util.Optional;
 

dhfs-parent/objects/src/main/java/com/usatiuk/objects/transaction/TransactionPrivate.java

@@ -1,8 +1,9 @@
-package com.usatiuk.dhfs.objects.transaction;
+package com.usatiuk.objects.transaction;
 
-import com.usatiuk.dhfs.objects.JData;
-import com.usatiuk.dhfs.objects.JObjectKey;
-import com.usatiuk.dhfs.objects.snapshot.SnapshotManager;
+import com.usatiuk.objects.JData;
+import com.usatiuk.objects.JDataVersionedWrapper;
+import com.usatiuk.objects.JObjectKey;
+import com.usatiuk.objects.snapshot.Snapshot;
 import com.usatiuk.dhfs.utils.AutoCloseableNoThrow;
 
 import java.util.Collection;
@@ -19,5 +20,5 @@ public interface TransactionPrivate extends Transaction, TransactionHandlePrivat
 
     Collection<Runnable> getOnCommit();
 
-    SnapshotManager.Snapshot snapshot();
+    Snapshot<JObjectKey, JDataVersionedWrapper> snapshot();
 }

dhfs-parent/objects/src/main/java/com/usatiuk/objects/transaction/TxCommitException.java

@@ -1,4 +1,4 @@
-package com.usatiuk.dhfs.objects;
+package com.usatiuk.objects.transaction;
 
 public class TxCommitException extends RuntimeException {
     public TxCommitException(String message) {

dhfs-parent/objects/src/main/java/com/usatiuk/objects/transaction/TxRecord.java

@@ -1,7 +1,7 @@
-package com.usatiuk.dhfs.objects.transaction;
+package com.usatiuk.objects.transaction;
 
-import com.usatiuk.dhfs.objects.JData;
-import com.usatiuk.dhfs.objects.JObjectKey;
+import com.usatiuk.objects.JData;
+import com.usatiuk.objects.JObjectKey;
 
 public class TxRecord {
     public interface TxObjectRecord<T> {

dhfs-parent/objects/src/main/resources/application.properties

@@ -4,5 +4,7 @@ dhfs.objects.lru.limit=134217728
 dhfs.objects.lru.print-stats=true
 dhfs.objects.lock_timeout_secs=15
 dhfs.objects.persistence.files.root=${HOME}/dhfs_default/data/objs
-quarkus.package.jar.decompiler.enabled=true
-dhfs.objects.persistence.snapshot-extra-checks=false
+dhfs.objects.persistence.snapshot-extra-checks=false
+dhfs.objects.transaction.never-lock=true
+quarkus.log.category."com.usatiuk.objects.iterators".level=INFO
+quarkus.log.category."com.usatiuk.objects.iterators".min-level=INFO

dhfs-parent/objects/src/test/java/com/usatiuk/dhfs/objects/snapshot/SnapshotKvIteratorTest.java

@@ -1,11 +0,0 @@
-package com.usatiuk.dhfs.objects.snapshot;
-
-import com.usatiuk.dhfs.objects.JObjectKey;
-import org.junit.jupiter.api.Test;
-
-import java.util.Map;
-
-public class SnapshotKvIteratorTest {
-
-
-}

dhfs-parent/objects/src/test/java/com/usatiuk/objects/Just.java

@@ -1,4 +1,4 @@
-package com.usatiuk.dhfs.objects;
+package com.usatiuk.objects;
 
 import org.junit.jupiter.api.Assertions;
 

dhfs-parent/objects/src/test/java/com/usatiuk/objects/ObjectsTestExtraChecksTest.java

@@ -1,9 +1,9 @@
-package com.usatiuk.dhfs.objects;
+package com.usatiuk.objects;
 
 import io.quarkus.test.junit.QuarkusTest;
 import io.quarkus.test.junit.TestProfile;
 
 @QuarkusTest
 @TestProfile(Profiles.ObjectsTestProfileExtraChecks.class)
-public class ObjectsTestExtraChecks extends ObjectsTestImpl {
+public class ObjectsTestExtraChecksTest extends ObjectsTestImpl {
 }

dhfs-parent/objects/src/test/java/com/usatiuk/objects/ObjectsTestImpl.java

@@ -1,9 +1,10 @@
-package com.usatiuk.dhfs.objects;
+package com.usatiuk.objects;
 
-import com.usatiuk.dhfs.objects.data.Parent;
-import com.usatiuk.dhfs.objects.persistence.IteratorStart;
-import com.usatiuk.dhfs.objects.transaction.LockingStrategy;
-import com.usatiuk.dhfs.objects.transaction.Transaction;
+import com.usatiuk.objects.data.Parent;
+import com.usatiuk.objects.iterators.IteratorStart;
+import com.usatiuk.objects.transaction.LockingStrategy;
+import com.usatiuk.objects.transaction.Transaction;
+import com.usatiuk.objects.transaction.TransactionManager;
 import io.quarkus.logging.Log;
 import jakarta.inject.Inject;
 import org.junit.jupiter.api.Assertions;
@@ -68,6 +69,30 @@ public abstract class ObjectsTestImpl {
         });
     }
 
+    @Test
+    void onCommitHookTest() {
+        txm.run(() -> {
+            var newParent = new Parent(JObjectKey.of("ParentOnCommitHook"), "John");
+            curTx.put(newParent);
+            curTx.onCommit(() -> txm.run(() -> {
+                curTx.put(new Parent(JObjectKey.of("ParentOnCommitHook2"), "John2"));
+            }));
+        });
+        txm.run(() -> {
+            curTx.onCommit(() -> txm.run(() -> {
+                curTx.put(new Parent(JObjectKey.of("ParentOnCommitHook3"), "John3"));
+            }));
+        });
+        txm.run(() -> {
+            var parent = curTx.get(Parent.class, new JObjectKey("ParentOnCommitHook")).orElse(null);
+            Assertions.assertEquals("John", parent.name());
+            var parent2 = curTx.get(Parent.class, new JObjectKey("ParentOnCommitHook2")).orElse(null);
+            Assertions.assertEquals("John2", parent2.name());
+            var parent3 = curTx.get(Parent.class, new JObjectKey("ParentOnCommitHook3")).orElse(null);
+            Assertions.assertEquals("John3", parent3.name());
+        });
+    }
+
     @Test
     void createGetObject() {
         txm.run(() -> {

dhfs-parent/objects/src/test/java/com/usatiuk/objects/ObjectsTestNoExtraChecksTest.java

@@ -1,9 +1,9 @@
-package com.usatiuk.dhfs.objects;
+package com.usatiuk.objects;
 
 import io.quarkus.test.junit.QuarkusTest;
 import io.quarkus.test.junit.TestProfile;
 
 @QuarkusTest
 @TestProfile(Profiles.ObjectsTestProfileNoExtraChecks.class)
-public class ObjectsTestNoExtraChecks extends ObjectsTestImpl {
+public class ObjectsTestNoExtraChecksTest extends ObjectsTestImpl {
 }

dhfs-parent/objects/src/test/java/com/usatiuk/objects/PreCommitTxHookTest.java

@@ -1,7 +1,9 @@
-package com.usatiuk.dhfs.objects;
+package com.usatiuk.objects;
 
-import com.usatiuk.dhfs.objects.data.Parent;
-import com.usatiuk.dhfs.objects.transaction.Transaction;
+import com.usatiuk.objects.data.Parent;
+import com.usatiuk.objects.transaction.PreCommitTxHook;
+import com.usatiuk.objects.transaction.Transaction;
+import com.usatiuk.objects.transaction.TransactionManager;
 import io.quarkus.test.junit.QuarkusTest;
 import io.quarkus.test.junit.TestProfile;
 import io.quarkus.test.junit.mockito.InjectSpy;

dhfs-parent/objects/src/test/java/com/usatiuk/objects/TempDataProfile.java

@@ -1,4 +1,4 @@
-package com.usatiuk.dhfs.objects;
+package com.usatiuk.objects;
 
 import io.quarkus.test.junit.QuarkusTestProfile;
 

dhfs-parent/objects/src/test/java/com/usatiuk/objects/TestDataCleaner.java

@@ -1,4 +1,4 @@
-package com.usatiuk.dhfs.objects;
+package com.usatiuk.objects;
 
 import io.quarkus.logging.Log;
 import io.quarkus.runtime.ShutdownEvent;

dhfs-parent/objects/src/test/java/com/usatiuk/objects/data/Kid.java

@@ -1,7 +1,7 @@
-package com.usatiuk.dhfs.objects.data;
+package com.usatiuk.objects.data;
 
-import com.usatiuk.dhfs.objects.JData;
-import com.usatiuk.dhfs.objects.JObjectKey;
+import com.usatiuk.objects.JData;
+import com.usatiuk.objects.JObjectKey;
 
 public record Kid(JObjectKey key, String name) implements JData {
     public Kid withName(String name) {

dhfs-parent/objects/src/test/java/com/usatiuk/objects/data/Parent.java

@@ -1,7 +1,7 @@
-package com.usatiuk.dhfs.objects.data;
+package com.usatiuk.objects.data;
 
-import com.usatiuk.dhfs.objects.JData;
-import com.usatiuk.dhfs.objects.JObjectKey;
+import com.usatiuk.objects.JData;
+import com.usatiuk.objects.JObjectKey;
 
 public record Parent(JObjectKey key, String name) implements JData {
     public Parent withName(String name) {

dhfs-parent/objects/src/test/java/com/usatiuk/objects/iterators/KeyPredicateKvIteratorTest.java

@@ -1,6 +1,6 @@
-package com.usatiuk.dhfs.objects;
+package com.usatiuk.objects.iterators;
 
-import com.usatiuk.dhfs.objects.persistence.IteratorStart;
+import com.usatiuk.objects.Just;
 import org.apache.commons.lang3.tuple.Pair;
 import org.junit.jupiter.api.Assertions;
 import org.junit.jupiter.api.Test;

dhfs-parent/objects/src/test/java/com/usatiuk/objects/iterators/MergingKvIteratorTest.java

@@ -1,6 +1,6 @@
-package com.usatiuk.dhfs.objects;
+package com.usatiuk.objects.iterators;
 
-import com.usatiuk.dhfs.objects.persistence.IteratorStart;
+import com.usatiuk.objects.Just;
 import org.apache.commons.lang3.tuple.Pair;
 import org.junit.jupiter.api.Assertions;
 import org.junit.jupiter.api.Test;
@@ -12,80 +12,6 @@ import java.util.NoSuchElementException;
 
 public class MergingKvIteratorTest {
 
-    private class SimpleIteratorWrapper<K extends Comparable<K>, V> implements CloseableKvIterator<K, V> {
-        private final Iterator<Pair<K, V>> _iterator;
-        private Pair<K, V> _next;
-
-        public SimpleIteratorWrapper(Iterator<Pair<K, V>> iterator) {
-            _iterator = iterator;
-            fillNext();
-        }
-
-        private void fillNext() {
-            while (_iterator.hasNext() && _next == null) {
-                _next = _iterator.next();
-            }
-        }
-
-        @Override
-        public K peekNextKey() {
-            if (_next == null) {
-                throw new NoSuchElementException();
-            }
-            return _next.getKey();
-        }
-
-        @Override
-        public void skip() {
-            if (_next == null) {
-                throw new NoSuchElementException();
-            }
-            _next = null;
-            fillNext();
-        }
-
-        @Override
-        public K peekPrevKey() {
-            throw new UnsupportedOperationException();
-        }
-
-        @Override
-        public Pair<K, V> prev() {
-            throw new UnsupportedOperationException();
-        }
-
-        @Override
-        public boolean hasPrev() {
-            throw new UnsupportedOperationException();
-        }
-
-        @Override
-        public void skipPrev() {
-            throw new UnsupportedOperationException();
-
-        }
-
-        @Override
-        public void close() {
-        }
-
-        @Override
-        public boolean hasNext() {
-            return _next != null;
-        }
-
-        @Override
-        public Pair<K, V> next() {
-            if (_next == null) {
-                throw new NoSuchElementException("No more elements");
-            }
-            var ret = _next;
-            _next = null;
-            fillNext();
-            return ret;
-        }
-    }
-
     @Test
     public void testTestIterator() {
         var list = List.of(Pair.of(1, 2), Pair.of(3, 4), Pair.of(5, 6));
@@ -345,4 +271,78 @@ public class MergingKvIteratorTest {
         }
         Assertions.assertFalse(mergingIterator2.hasNext());
     }
+
+    private class SimpleIteratorWrapper<K extends Comparable<K>, V> implements CloseableKvIterator<K, V> {
+        private final Iterator<Pair<K, V>> _iterator;
+        private Pair<K, V> _next;
+
+        public SimpleIteratorWrapper(Iterator<Pair<K, V>> iterator) {
+            _iterator = iterator;
+            fillNext();
+        }
+
+        private void fillNext() {
+            while (_iterator.hasNext() && _next == null) {
+                _next = _iterator.next();
+            }
+        }
+
+        @Override
+        public K peekNextKey() {
+            if (_next == null) {
+                throw new NoSuchElementException();
+            }
+            return _next.getKey();
+        }
+
+        @Override
+        public void skip() {
+            if (_next == null) {
+                throw new NoSuchElementException();
+            }
+            _next = null;
+            fillNext();
+        }
+
+        @Override
+        public K peekPrevKey() {
+            throw new UnsupportedOperationException();
+        }
+
+        @Override
+        public Pair<K, V> prev() {
+            throw new UnsupportedOperationException();
+        }
+
+        @Override
+        public boolean hasPrev() {
+            throw new UnsupportedOperationException();
+        }
+
+        @Override
+        public void skipPrev() {
+            throw new UnsupportedOperationException();
+
+        }
+
+        @Override
+        public void close() {
+        }
+
+        @Override
+        public boolean hasNext() {
+            return _next != null;
+        }
+
+        @Override
+        public Pair<K, V> next() {
+            if (_next == null) {
+                throw new NoSuchElementException("No more elements");
+            }
+            var ret = _next;
+            _next = null;
+            fillNext();
+            return ret;
+        }
+    }
 }

dhfs-parent/objects/src/test/java/com/usatiuk/objects/iterators/NavigableMapKvIteratorTest.java

@@ -1,6 +1,6 @@
-package com.usatiuk.dhfs.objects;
+package com.usatiuk.objects.iterators;
 
-import com.usatiuk.dhfs.objects.persistence.IteratorStart;
+import com.usatiuk.objects.Just;
 import org.apache.commons.lang3.tuple.Pair;
 import org.junit.jupiter.api.Assertions;
 import org.junit.jupiter.api.Test;

dhfs-parent/objects/src/test/java/com/usatiuk/objects/iterators/PredicateKvIteratorTest.java

@@ -1,6 +1,6 @@
-package com.usatiuk.dhfs.objects;
+package com.usatiuk.objects.iterators;
 
-import com.usatiuk.dhfs.objects.persistence.IteratorStart;
+import com.usatiuk.objects.Just;
 import org.apache.commons.lang3.tuple.Pair;
 import org.junit.jupiter.api.Assertions;
 import org.junit.jupiter.api.Test;

dhfs-parent/objects/src/test/java/com/usatiuk/objects/snapshot/SnapshotKvIteratorTest.java

@@ -0,0 +1,6 @@
+package com.usatiuk.objects.snapshot;
+
+public class SnapshotKvIteratorTest {
+
+
+}

dhfs-parent/objects/src/test/java/com/usatiuk/objects/stores/LmdbKvIteratorTest.java

@@ -1,10 +1,11 @@
-package com.usatiuk.dhfs.objects.persistence;
+package com.usatiuk.objects.stores;
 
 
 import com.google.protobuf.ByteString;
-import com.usatiuk.dhfs.objects.JObjectKey;
-import com.usatiuk.dhfs.objects.Just;
-import com.usatiuk.dhfs.objects.TempDataProfile;
+import com.usatiuk.objects.JObjectKey;
+import com.usatiuk.objects.Just;
+import com.usatiuk.objects.TempDataProfile;
+import com.usatiuk.objects.iterators.IteratorStart;
 import io.quarkus.test.junit.QuarkusTest;
 import io.quarkus.test.junit.TestProfile;
 import jakarta.inject.Inject;
@@ -37,7 +38,14 @@ public class LmdbKvIteratorTest {
                 ), -1, Runnable::run
         );
 
-        var iterator = store.getIterator(IteratorStart.LE, JObjectKey.of(Long.toString(3)));
+        var iterator = store.getIterator(IteratorStart.GE, JObjectKey.of(""));
+        Just.checkIterator(iterator, List.of(Pair.of(JObjectKey.of(Long.toString(1)), ByteString.copyFrom(new byte[]{2})),
+                Pair.of(JObjectKey.of(Long.toString(2)), ByteString.copyFrom(new byte[]{3})),
+                Pair.of(JObjectKey.of(Long.toString(3)), ByteString.copyFrom(new byte[]{4}))));
+        Assertions.assertFalse(iterator.hasNext());
+        iterator.close();
+
+        iterator = store.getIterator(IteratorStart.LE, JObjectKey.of(Long.toString(3)));
         Just.checkIterator(iterator, Pair.of(JObjectKey.of(Long.toString(3)), ByteString.copyFrom(new byte[]{4})));
         Assertions.assertFalse(iterator.hasNext());
         iterator.close();

dhfs-parent/pom.xml

@@ -29,7 +29,7 @@
         <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
         <quarkus.platform.artifact-id>quarkus-bom</quarkus.platform.artifact-id>
         <quarkus.platform.group-id>io.quarkus.platform</quarkus.platform.group-id>
-        <quarkus.platform.version>3.15.2</quarkus.platform.version>
+        <quarkus.platform.version>3.20.0</quarkus.platform.version>
         <surefire-plugin.version>3.5.2</surefire-plugin.version>
         <dhfs.native-libs-dir>${project.parent.build.outputDirectory}/native</dhfs.native-libs-dir>
     </properties>

dhfs-parent/server-old/.dockerignore

@@ -1,5 +0,0 @@
-*
-!target/*-runner
-!target/*-runner.jar
-!target/lib/*
-!target/quarkus-app/*

dhfs-parent/server-old/.gitignore

@@ -1,43 +0,0 @@
-#Maven
-target/
-pom.xml.tag
-pom.xml.releaseBackup
-pom.xml.versionsBackup
-release.properties
-.flattened-pom.xml
-
-# Eclipse
-.project
-.classpath
-.settings/
-bin/
-
-# IntelliJ
-.idea
-*.ipr
-*.iml
-*.iws
-
-# NetBeans
-nb-configuration.xml
-
-# Visual Studio Code
-.vscode
-.factorypath
-
-# OSX
-.DS_Store
-
-# Vim
-*.swp
-*.swo
-
-# patch
-*.orig
-*.rej
-
-# Local environment
-.env
-
-# Plugin directory
-/.quarkus/cli/plugins/

dhfs-parent/server-old/Dockerfile

@@ -1,2 +0,0 @@
-FROM azul/zulu-openjdk-debian:21-jre-latest
-RUN apt update && apt install -y libfuse2 curl