Merge pull request #26 from Nexus-Mods/support-retractions

Adds support for retractions
Nexus-Mods · Apr 1, 2024 · 1b54eb4 · 1b54eb4
2 parents 3221ae4 + 2a8a6c1
commit 1b54eb4
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Showing 25 changed files with 190 additions and 75 deletions.
diff --git a/benchmarks/OneBillionDatomsTest/Program.cs b/benchmarks/OneBillionDatomsTest/Program.cs
@@ -60,7 +60,7 @@
     var tasks = new List<Task<(TimeSpan Time, int loaded)>>();
 
 
-    for (int i = 0; i < 4; i++)
+    for (int i = 0; i < 1; i++)
     {
         var task = Task.Run(() =>
         {

diff --git a/src/NexusMods.MneumonicDB.Abstractions/IAttribute.cs b/src/NexusMods.MneumonicDB.Abstractions/IAttribute.cs
@@ -69,6 +69,14 @@ public interface IAttribute<TVal> : IAttribute
     /// <returns></returns>
     public static abstract IWriteDatom Assert(EntityId e, TVal v);
 
+    /// <summary>
+    ///     Construct a new write Datom for the retraction of the given entity and value
+    /// </summary>
+    /// <param name="e"></param>
+    /// <param name="v"></param>
+    /// <returns></returns>
+    public static abstract IWriteDatom Retract(EntityId e, TVal v);
+
     /// <summary>
     /// Gets the serializer for the attribute
     /// </summary>

diff --git a/src/NexusMods.MneumonicDB.Abstractions/IDatomStore.cs b/src/NexusMods.MneumonicDB.Abstractions/IDatomStore.cs
@@ -40,53 +40,6 @@ public interface IDatomStore : IDisposable
     /// <param name="newAttrs"></param>
     Task RegisterAttributes(IEnumerable<DbAttribute> newAttrs);
 
-    /// <summary>
-    ///     Gets the entities that have the given attribute that reference the given entity id.
-    /// </summary>
-    IEnumerable<EntityId> GetReferencesToEntityThroughAttribute<TAttribute>(EntityId id, TxId txId)
-        where TAttribute : IAttribute<EntityId>;
-
-    /// <summary>
-    ///     Gets the value of the given attribute for the given entity id where the transaction id exactly matches the given
-    ///     txId.
-    /// </summary>
-    bool TryGetExact<TAttr, TValue>(EntityId e, TxId tx, out TValue val) where TAttr : IAttribute<TValue>;
-
-    /// <summary>
-    ///     Gets the latest value of the given attribute for the given entity id where the transaction id is less than or equal
-    ///     to the given txId.
-    /// </summary>
-    bool TryGetLatest<TAttribute, TValue>(EntityId e, TxId tx, out TValue value) where TAttribute : IAttribute<TValue>;
-
-    /// <summary>
-    ///     Gets all the entities that have the given attribute.
-    /// </summary>
-    IEnumerable<EntityId> GetEntitiesWithAttribute<TAttribute>(TxId tx) where TAttribute : IAttribute;
-
-    /// <summary>
-    ///     Gets all the attributes for the given entity id where the transaction id is less than or equal to the given txId.
-    /// </summary>
-    IEnumerable<IReadDatom> GetAttributesForEntity(EntityId realId, TxId txId);
-
-    /// <summary>
-    ///     Gets the maximum entity id in the store.
-    /// </summary>
-    EntityId GetMaxEntityId();
-
-    /// <summary>
-    ///     Gets the type of the read datom for the given attribute.
-    /// </summary>
-    Type GetReadDatomType(Type attribute);
-
-
-    /// <summary>
-    ///     Get all the datoms in a given index, not super useful as this may return a TOOON of datoms.
-    /// </summary>
-    /// <param name="snapshot"></param>
-    /// <param name="type"></param>
-    /// <returns></returns>
-    public IEnumerable<IReadDatom> Datoms(ISnapshot snapshot, IndexType type);
-
     /// <summary>
     ///     Create a snapshot of the current state of the store.
     /// </summary>

diff --git a/src/NexusMods.MneumonicDB.Abstractions/ScalarAttribute.cs b/src/NexusMods.MneumonicDB.Abstractions/ScalarAttribute.cs
@@ -105,7 +105,18 @@ public static IWriteDatom Assert(EntityId e, TValueType v)
         return new WriteDatom
         {
             E = e,
-            V = v
+            V = v,
+            IsRetract = false
+        };
+    }
+
+    public static IWriteDatom Retract(EntityId e, TValueType v)
+    {
+        return new WriteDatom
+        {
+            E = e,
+            V = v,
+            IsRetract = true
         };
     }
 
@@ -146,11 +157,16 @@ public TValueType Read(ReadOnlySpan<byte> buffer)
         /// </summary>
         public required EntityId E { get; init; }
 
+        /// <summary>
+        ///     True if this is a retraction
+        /// </summary>
+        public required bool IsRetract { get; init; }
+
         public void Explode<TWriter>(IAttributeRegistry registry, Func<EntityId, EntityId> remapFn,
             out EntityId e, out AttributeId a, TWriter vWriter, out bool isRetract)
             where TWriter : IBufferWriter<byte>
         {
-            isRetract = false;
+            isRetract = IsRetract;
             e = EntityId.From(Ids.IsPartition(E.Value, Ids.Partition.Tmp) ? remapFn(E).Value : E.Value);
 
             if (V is EntityId id)

diff --git a/src/NexusMods.MneumonicDB.Storage/DatomStore.cs b/src/NexusMods.MneumonicDB.Storage/DatomStore.cs
@@ -201,15 +201,6 @@ public ISnapshot GetSnapshot()
         return _backend.GetSnapshot();
     }
 
-
-    public IEnumerable<IReadDatom> Datoms(ISnapshot snapshot, IndexType type)
-    {
-        using var source = snapshot.GetIterator(type);
-        var iter = source.SeekStart();
-        foreach (var datom in iter.Resolve())
-            yield return datom;
-    }
-
     public void Dispose()
     {
         _updatesSubject.Dispose();
@@ -326,7 +317,7 @@ private EntityId MaybeRemap(EntityId id, Dictionary<EntityId, EntityId> remaps,
     }
 
 
-    private void Log(PendingTransaction pendingTransaction, out StoreResult result)
+    private unsafe void Log(PendingTransaction pendingTransaction, out StoreResult result)
     {
         var thisTx = TxId.From(_asOfTxId.Value + 1);
 
@@ -345,9 +336,9 @@ private void Log(PendingTransaction pendingTransaction, out StoreResult result)
             }
 
             var isRemapped = Ids.IsPartition(datom.E.Value, Ids.Partition.Tmp);
-            datom.Explode(_registry, remapFn, out var e, out var a, _writer, out var isAssert);
+            datom.Explode(_registry, remapFn, out var e, out var a, _writer, out var isRetract);
             var keyPrefix = _writer.GetWrittenSpanWritable().CastFast<byte, KeyPrefix>();
-            keyPrefix[0].Set(e, a, thisTx, isAssert);
+            keyPrefix[0].Set(e, a, thisTx, isRetract);
 
             var attr = _registry.GetAttribute(a);
             var isReference = attr.IsReference;
@@ -357,8 +348,19 @@ private void Log(PendingTransaction pendingTransaction, out StoreResult result)
             if (!isRemapped)
                 havePrevious = GetPrevious(keyPrefix[0]);
 
+            // Put it in the tx log first
+            var newSpan = _writer.GetWrittenSpan();
+            _txLog.Put(batch, newSpan);
+
+            // Remove the previous if it exists
             if (havePrevious)
             {
+                var prevValSpan = _prevWriter.GetWrittenSpan().SliceFast(sizeof(KeyPrefix));
+                var currValSpan = _writer.GetWrittenSpan().SliceFast(sizeof(KeyPrefix));
+
+                if (!isRetract && prevValSpan.SequenceEqual(currValSpan))
+                    continue;
+
                 // Move the previous to the history index
                 var span = _prevWriter.GetWrittenSpan();
                 _eavtCurrent.Delete(batch, span);
@@ -380,16 +382,30 @@ private void Log(PendingTransaction pendingTransaction, out StoreResult result)
                 }
             }
 
-            var newSpan = _writer.GetWrittenSpan();
-            _eavtCurrent.Put(batch, newSpan);
-            _aevtCurrent.Put(batch, newSpan);
-            _txLog.Put(batch, newSpan);
 
-            if (isReference)
-                _vaetCurrent.Put(batch, newSpan);
+            // Add new state
+            if (!isRetract)
+            {
+                _eavtCurrent.Put(batch, newSpan);
+                _aevtCurrent.Put(batch, newSpan);
+
+                if (isReference)
+                    _vaetCurrent.Put(batch, newSpan);
 
-            if (isIndexed)
-                _avetCurrent.Put(batch, newSpan);
+                if (isIndexed)
+                    _avetCurrent.Put(batch, newSpan);
+            }
+            else
+            {
+                _eavtHistory.Put(batch, newSpan);
+                _aevtHistory.Put(batch, newSpan);
+
+                if (isReference)
+                    _vaetHistory.Put(batch, newSpan);
+
+                if (isIndexed)
+                    _aevtHistory.Put(batch, newSpan);
+            }
         }
 
         var swWrite = Stopwatch.StartNew();

diff --git a/tests/NexusMods.MneumonicDB.Storage.Tests/ABackendTest.cs b/tests/NexusMods.MneumonicDB.Storage.Tests/ABackendTest.cs
@@ -3,6 +3,7 @@
 using NexusMods.MneumonicDB.TestModel.ComplexModel.Attributes;
 using NexusMods.MneumonicDB.TestModel.Helpers;
 using NexusMods.Hashing.xxHash64;
+using NexusMods.MneumonicDB.Abstractions.DatomIterators;
 using NexusMods.Paths;
 using FileAttributes = NexusMods.MneumonicDB.TestModel.ComplexModel.Attributes.FileAttributes;
 
@@ -55,10 +56,47 @@ public async Task InsertedDatomsShowUpInTheIndex(IndexType type)
             FileAttributes.ModId.Assert(id1, modId2)
         ]);
 
-        var snapshot = DatomStore.GetSnapshot();
-        var results = DatomStore.Datoms(snapshot, type).ToList();
+        using var iterator = tx.Snapshot.GetIterator(type);
+        await Verify(iterator.SeekStart().Resolve().ToTable(Registry))
+            .UseDirectory("BackendTestVerifyData")
+            .UseParameters(type);
+    }
+
+    [Theory]
+    [InlineData(IndexType.TxLog)]
+    [InlineData(IndexType.EAVTHistory)]
+    [InlineData(IndexType.EAVTCurrent)]
+    [InlineData(IndexType.AEVTCurrent)]
+    [InlineData(IndexType.AEVTHistory)]
+    [InlineData(IndexType.VAETCurrent)]
+    [InlineData(IndexType.VAETHistory)]
+    [InlineData(IndexType.AVETCurrent)]
+    [InlineData(IndexType.AVETHistory)]
+    public async Task RetractedValuesAreSupported(IndexType type)
+    {
+        var id = NextTempId();
+        var modId = NextTempId();
+
+        var tx1 = await DatomStore.Transact([
+            FileAttributes.Path.Assert(id, "/foo/bar"),
+            FileAttributes.Hash.Assert(id, Hash.From(0xDEADBEEF)),
+            FileAttributes.Size.Assert(id, Size.From(42)),
+            FileAttributes.ModId.Assert(id, modId),
+        ]);
+
+        id = tx1.Remaps[id];
+        modId = tx1.Remaps[modId];
+
+        var tx2 = await DatomStore.Transact([
+            FileAttributes.Path.Retract(id, "/foo/bar"),
+            FileAttributes.Hash.Retract(id, Hash.From(0xDEADBEEF)),
+            FileAttributes.Size.Retract(id, Size.From(42)),
+            FileAttributes.ModId.Retract(id, modId)
+        ]);
+
 
-        await Verify(results.ToTable(Registry))
+        using var iterator = tx2.Snapshot.GetIterator(type);
+        await Verify(iterator.SeekStart().Resolve().ToTable(Registry))
             .UseDirectory("BackendTestVerifyData")
             .UseParameters(type);
     }

diff --git a/...endTestVerifyData/InMemoryTests.RetractedValuesAreSupported_type=AEVTCurrent.verified.txt b/...endTestVerifyData/InMemoryTests.RetractedValuesAreSupported_type=AEVTCurrent.verified.txt
@@ -0,0 +1,4 @@
++ | 0000000000000001 | (0001) UniqueId                 | NexusMods.MneumonicDB.DatomStore/UniqueId        | 0100000000000001
++ | 0000000000000002 | (0001) UniqueId                 | NexusMods.MneumonicDB....tore/ValueSerializerId  | 0100000000000001
++ | 0000000000000001 | (0002) ValueSerializerId        | NexusMods.MneumonicDB....izers/SymbolSerializer  | 0100000000000001
++ | 0000000000000002 | (0002) ValueSerializerId        | NexusMods.MneumonicDB....izers/SymbolSerializer  | 0100000000000001
diff --git a/...endTestVerifyData/InMemoryTests.RetractedValuesAreSupported_type=AEVTHistory.verified.txt b/...endTestVerifyData/InMemoryTests.RetractedValuesAreSupported_type=AEVTHistory.verified.txt
@@ -0,0 +1,8 @@
++ | 0200000000000001 | (0014) Path                     | /foo/bar                                         | 0100000000000002
+- | 0200000000000001 | (0014) Path                     | /foo/bar                                         | 0100000000000003
++ | 0200000000000001 | (0015) Hash                     | 0x00000000DEADBEEF                               | 0100000000000002
+- | 0200000000000001 | (0015) Hash                     | 0x00000000DEADBEEF                               | 0100000000000003
++ | 0200000000000001 | (0016) Size                     | 42 B                                             | 0100000000000002
+- | 0200000000000001 | (0016) Size                     | 42 B                                             | 0100000000000003
++ | 0200000000000001 | (0017) ModId                    | 0200000000000002                                 | 0100000000000002
+- | 0200000000000001 | (0017) ModId                    | 0200000000000002                                 | 0100000000000003
diff --git a/...endTestVerifyData/InMemoryTests.RetractedValuesAreSupported_type=AVETCurrent.verified.txt b/...endTestVerifyData/InMemoryTests.RetractedValuesAreSupported_type=AVETCurrent.verified.txt
@@ -0,0 +1 @@
+emptyString
diff --git a/...endTestVerifyData/InMemoryTests.RetractedValuesAreSupported_type=AVETHistory.verified.txt b/...endTestVerifyData/InMemoryTests.RetractedValuesAreSupported_type=AVETHistory.verified.txt
@@ -0,0 +1,2 @@
++ | 0200000000000001 | (0014) Path                     | /foo/bar                                         | 0100000000000002
++ | 0200000000000001 | (0015) Hash                     | 0x00000000DEADBEEF                               | 0100000000000002
diff --git a/...endTestVerifyData/InMemoryTests.RetractedValuesAreSupported_type=EAVTCurrent.verified.txt b/...endTestVerifyData/InMemoryTests.RetractedValuesAreSupported_type=EAVTCurrent.verified.txt
@@ -0,0 +1,4 @@
++ | 0000000000000001 | (0001) UniqueId                 | NexusMods.MneumonicDB.DatomStore/UniqueId        | 0100000000000001
++ | 0000000000000001 | (0002) ValueSerializerId        | NexusMods.MneumonicDB....izers/SymbolSerializer  | 0100000000000001
++ | 0000000000000002 | (0001) UniqueId                 | NexusMods.MneumonicDB....tore/ValueSerializerId  | 0100000000000001
++ | 0000000000000002 | (0002) ValueSerializerId        | NexusMods.MneumonicDB....izers/SymbolSerializer  | 0100000000000001
diff --git a/...endTestVerifyData/InMemoryTests.RetractedValuesAreSupported_type=EAVTHistory.verified.txt b/...endTestVerifyData/InMemoryTests.RetractedValuesAreSupported_type=EAVTHistory.verified.txt
@@ -0,0 +1,8 @@
++ | 0200000000000001 | (0014) Path                     | /foo/bar                                         | 0100000000000002
+- | 0200000000000001 | (0014) Path                     | /foo/bar                                         | 0100000000000003
++ | 0200000000000001 | (0015) Hash                     | 0x00000000DEADBEEF                               | 0100000000000002
+- | 0200000000000001 | (0015) Hash                     | 0x00000000DEADBEEF                               | 0100000000000003
++ | 0200000000000001 | (0016) Size                     | 42 B                                             | 0100000000000002
+- | 0200000000000001 | (0016) Size                     | 42 B                                             | 0100000000000003
++ | 0200000000000001 | (0017) ModId                    | 0200000000000002                                 | 0100000000000002
+- | 0200000000000001 | (0017) ModId                    | 0200000000000002                                 | 0100000000000003
diff --git a/...s/BackendTestVerifyData/InMemoryTests.RetractedValuesAreSupported_type=TxLog.verified.txt b/...s/BackendTestVerifyData/InMemoryTests.RetractedValuesAreSupported_type=TxLog.verified.txt
@@ -0,0 +1,12 @@
++ | 0000000000000001 | (0001) UniqueId                 | NexusMods.MneumonicDB.DatomStore/UniqueId        | 0100000000000001
++ | 0000000000000001 | (0002) ValueSerializerId        | NexusMods.MneumonicDB....izers/SymbolSerializer  | 0100000000000001
++ | 0000000000000002 | (0001) UniqueId                 | NexusMods.MneumonicDB....tore/ValueSerializerId  | 0100000000000001
++ | 0000000000000002 | (0002) ValueSerializerId        | NexusMods.MneumonicDB....izers/SymbolSerializer  | 0100000000000001
++ | 0200000000000001 | (0014) Path                     | /foo/bar                                         | 0100000000000002
++ | 0200000000000001 | (0015) Hash                     | 0x00000000DEADBEEF                               | 0100000000000002
++ | 0200000000000001 | (0016) Size                     | 42 B                                             | 0100000000000002
++ | 0200000000000001 | (0017) ModId                    | 0200000000000002                                 | 0100000000000002
+- | 0200000000000001 | (0014) Path                     | /foo/bar                                         | 0100000000000003
+- | 0200000000000001 | (0015) Hash                     | 0x00000000DEADBEEF                               | 0100000000000003
+- | 0200000000000001 | (0016) Size                     | 42 B                                             | 0100000000000003
+- | 0200000000000001 | (0017) ModId                    | 0200000000000002                                 | 0100000000000003
diff --git a/...endTestVerifyData/InMemoryTests.RetractedValuesAreSupported_type=VAETCurrent.verified.txt b/...endTestVerifyData/InMemoryTests.RetractedValuesAreSupported_type=VAETCurrent.verified.txt
@@ -0,0 +1 @@
+emptyString
diff --git a/...endTestVerifyData/InMemoryTests.RetractedValuesAreSupported_type=VAETHistory.verified.txt b/...endTestVerifyData/InMemoryTests.RetractedValuesAreSupported_type=VAETHistory.verified.txt
@@ -0,0 +1,2 @@
++ | 0200000000000001 | (0017) ModId                    | 0200000000000002                                 | 0100000000000002
+- | 0200000000000001 | (0017) ModId                    | 0200000000000002                                 | 0100000000000003
diff --git a/...s/BackendTestVerifyData/RocksDB.RetractedValuesAreSupported_type=AEVTCurrent.verified.txt b/...s/BackendTestVerifyData/RocksDB.RetractedValuesAreSupported_type=AEVTCurrent.verified.txt
@@ -0,0 +1,4 @@
++ | 0000000000000001 | (0001) UniqueId                 | NexusMods.MneumonicDB.DatomStore/UniqueId        | 0100000000000001
++ | 0000000000000002 | (0001) UniqueId                 | NexusMods.MneumonicDB....tore/ValueSerializerId  | 0100000000000001
++ | 0000000000000001 | (0002) ValueSerializerId        | NexusMods.MneumonicDB....izers/SymbolSerializer  | 0100000000000001
++ | 0000000000000002 | (0002) ValueSerializerId        | NexusMods.MneumonicDB....izers/SymbolSerializer  | 0100000000000001
diff --git a/...s/BackendTestVerifyData/RocksDB.RetractedValuesAreSupported_type=AEVTHistory.verified.txt b/...s/BackendTestVerifyData/RocksDB.RetractedValuesAreSupported_type=AEVTHistory.verified.txt
@@ -0,0 +1,8 @@
++ | 0200000000000001 | (0014) Path                     | /foo/bar                                         | 0100000000000002
+- | 0200000000000001 | (0014) Path                     | /foo/bar                                         | 0100000000000003
++ | 0200000000000001 | (0015) Hash                     | 0x00000000DEADBEEF                               | 0100000000000002
+- | 0200000000000001 | (0015) Hash                     | 0x00000000DEADBEEF                               | 0100000000000003
++ | 0200000000000001 | (0016) Size                     | 42 B                                             | 0100000000000002
+- | 0200000000000001 | (0016) Size                     | 42 B                                             | 0100000000000003
++ | 0200000000000001 | (0017) ModId                    | 0200000000000002                                 | 0100000000000002
+- | 0200000000000001 | (0017) ModId                    | 0200000000000002                                 | 0100000000000003
diff --git a/...s/BackendTestVerifyData/RocksDB.RetractedValuesAreSupported_type=AVETCurrent.verified.txt b/...s/BackendTestVerifyData/RocksDB.RetractedValuesAreSupported_type=AVETCurrent.verified.txt
@@ -0,0 +1 @@
+emptyString
diff --git a/...s/BackendTestVerifyData/RocksDB.RetractedValuesAreSupported_type=AVETHistory.verified.txt b/...s/BackendTestVerifyData/RocksDB.RetractedValuesAreSupported_type=AVETHistory.verified.txt
@@ -0,0 +1,2 @@
++ | 0200000000000001 | (0014) Path                     | /foo/bar                                         | 0100000000000002
++ | 0200000000000001 | (0015) Hash                     | 0x00000000DEADBEEF                               | 0100000000000002
diff --git a/...s/BackendTestVerifyData/RocksDB.RetractedValuesAreSupported_type=EAVTCurrent.verified.txt b/...s/BackendTestVerifyData/RocksDB.RetractedValuesAreSupported_type=EAVTCurrent.verified.txt
@@ -0,0 +1,4 @@
++ | 0000000000000001 | (0001) UniqueId                 | NexusMods.MneumonicDB.DatomStore/UniqueId        | 0100000000000001
++ | 0000000000000001 | (0002) ValueSerializerId        | NexusMods.MneumonicDB....izers/SymbolSerializer  | 0100000000000001
++ | 0000000000000002 | (0001) UniqueId                 | NexusMods.MneumonicDB....tore/ValueSerializerId  | 0100000000000001
++ | 0000000000000002 | (0002) ValueSerializerId        | NexusMods.MneumonicDB....izers/SymbolSerializer  | 0100000000000001
diff --git a/...s/BackendTestVerifyData/RocksDB.RetractedValuesAreSupported_type=EAVTHistory.verified.txt b/...s/BackendTestVerifyData/RocksDB.RetractedValuesAreSupported_type=EAVTHistory.verified.txt
@@ -0,0 +1,8 @@
++ | 0200000000000001 | (0014) Path                     | /foo/bar                                         | 0100000000000002
+- | 0200000000000001 | (0014) Path                     | /foo/bar                                         | 0100000000000003
++ | 0200000000000001 | (0015) Hash                     | 0x00000000DEADBEEF                               | 0100000000000002
+- | 0200000000000001 | (0015) Hash                     | 0x00000000DEADBEEF                               | 0100000000000003
++ | 0200000000000001 | (0016) Size                     | 42 B                                             | 0100000000000002
+- | 0200000000000001 | (0016) Size                     | 42 B                                             | 0100000000000003
++ | 0200000000000001 | (0017) ModId                    | 0200000000000002                                 | 0100000000000002
+- | 0200000000000001 | (0017) ModId                    | 0200000000000002                                 | 0100000000000003
diff --git a/...e.Tests/BackendTestVerifyData/RocksDB.RetractedValuesAreSupported_type=TxLog.verified.txt b/...e.Tests/BackendTestVerifyData/RocksDB.RetractedValuesAreSupported_type=TxLog.verified.txt
@@ -0,0 +1,12 @@
++ | 0000000000000001 | (0001) UniqueId                 | NexusMods.MneumonicDB.DatomStore/UniqueId        | 0100000000000001
++ | 0000000000000001 | (0002) ValueSerializerId        | NexusMods.MneumonicDB....izers/SymbolSerializer  | 0100000000000001
++ | 0000000000000002 | (0001) UniqueId                 | NexusMods.MneumonicDB....tore/ValueSerializerId  | 0100000000000001
++ | 0000000000000002 | (0002) ValueSerializerId        | NexusMods.MneumonicDB....izers/SymbolSerializer  | 0100000000000001
++ | 0200000000000001 | (0014) Path                     | /foo/bar                                         | 0100000000000002
++ | 0200000000000001 | (0015) Hash                     | 0x00000000DEADBEEF                               | 0100000000000002
++ | 0200000000000001 | (0016) Size                     | 42 B                                             | 0100000000000002
++ | 0200000000000001 | (0017) ModId                    | 0200000000000002                                 | 0100000000000002
+- | 0200000000000001 | (0014) Path                     | /foo/bar                                         | 0100000000000003
+- | 0200000000000001 | (0015) Hash                     | 0x00000000DEADBEEF                               | 0100000000000003
+- | 0200000000000001 | (0016) Size                     | 42 B                                             | 0100000000000003
+- | 0200000000000001 | (0017) ModId                    | 0200000000000002                                 | 0100000000000003
diff --git a/...s/BackendTestVerifyData/RocksDB.RetractedValuesAreSupported_type=VAETCurrent.verified.txt b/...s/BackendTestVerifyData/RocksDB.RetractedValuesAreSupported_type=VAETCurrent.verified.txt
@@ -0,0 +1 @@
+emptyString
Original file line number	Diff line number	Diff line change
		@@ -0,0 +1,2 @@
		+ \| 0200000000000001 \| (0014) Path \| /foo/bar \| 0100000000000002
		+ \| 0200000000000001 \| (0015) Hash \| 0x00000000DEADBEEF \| 0100000000000002
Original file line number	Diff line number	Diff line change
		@@ -0,0 +1,2 @@
		+ \| 0200000000000001 \| (0017) ModId \| 0200000000000002 \| 0100000000000002
		- \| 0200000000000001 \| (0017) ModId \| 0200000000000002 \| 0100000000000003