Colleect garbage from write ahead log of mutable segment.

koculu · Jun 17, 2023 · ea5e49e · ea5e49e
1 parent d10e0cc
commit ea5e49e
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Showing 4 changed files with 25 additions and 11 deletions.
diff --git a/src/ZoneTree.UnitTests/FixedSizeKeyAndValueTests.cs b/src/ZoneTree.UnitTests/FixedSizeKeyAndValueTests.cs
@@ -127,6 +127,7 @@ public void IntStringGarbageCollectionTest()
         }
 
         // reload tree and check the length
+        for (var i = 0; i < 3; ++i)
         {
             using var data = new ZoneTreeFactory<int, string>()
                 .Configure(options => options.EnableSingleSegmentGarbageCollection = true)

diff --git a/src/ZoneTree/Core/ZoneTreeLoader.cs b/src/ZoneTree/Core/ZoneTreeLoader.cs
@@ -6,6 +6,7 @@
 using Tenray.ZoneTree.Segments.InMemory;
 using Tenray.ZoneTree.Segments.MultiPart;
 using Tenray.ZoneTree.Segments.NullDisk;
+using Tenray.ZoneTree.WAL;
 
 namespace Tenray.ZoneTree.Core;
 
@@ -145,15 +146,17 @@ void ValidateSegmentOrder()
         }
     }
 
-    void LoadMutableSegment(long maximumOpIndex,
+    IWriteAheadLog<TKey, TValue> LoadMutableSegment(long maximumOpIndex,
         bool collectGarbage)
     {
         var loader = new MutableSegmentLoader<TKey, TValue>(Options);
         MutableSegment = loader
             .LoadMutableSegment(
                 ZoneTreeMeta.MutableSegment,
                 maximumOpIndex,
-                collectGarbage);
+                collectGarbage,
+                out var wal);
+        return wal;
     }
 
     long LoadReadOnlySegments()
@@ -237,7 +240,21 @@ void SetMaximumId()
         SetMaximumId();
         var maximumOpIndex = LoadReadOnlySegments();
         bool collectGarbage = Options.EnableSingleSegmentGarbageCollection && !ZoneTreeMeta.HasDiskSegment && ReadOnlySegments.Count == 0;
-        LoadMutableSegment(maximumOpIndex, collectGarbage);
+        var mutableSegmentWal = LoadMutableSegment(maximumOpIndex, collectGarbage);
+        if (collectGarbage)
+        {
+            var len = MutableSegment.Length;
+            var keys = new TKey[len];
+            var values = new TValue[len];
+            var iterator = MutableSegment.GetSeekableIterator();
+            var i = 0;
+            while (iterator.Next())
+            {
+                keys[i] = iterator.CurrentKey;
+                values[i++] = iterator.CurrentValue;
+            }
+            mutableSegmentWal.ReplaceWriteAheadLog(keys, values, true);
+        }
         LoadDiskSegment();
         LoadBottomSegments();
         var zoneTree = new ZoneTree<TKey, TValue>(Options, ZoneTreeMeta,

diff --git a/src/ZoneTree/Options/ZoneTreeOptions.cs b/src/ZoneTree/Options/ZoneTreeOptions.cs
@@ -256,12 +256,6 @@ public void Validate()
     /// </summary>
     public DeleteValueConfigurationValidation DeleteValueConfigurationValidation { get; set; }
 
-    /// <summary>
-    /// If ZoneTree contains single segment (which is the mutable segment),
-    /// there is the opportunity to hard delete the soft deleted values.
-    /// If enabled, tree performs a garbage collection on load if applicable.
-    /// </summary>
-    /// 
     /// <summary>
     /// If the ZoneTree contains only a single segment (which is the mutable segment),
     /// there is an opportunity to perform a hard delete of the soft deleted values.

diff --git a/src/ZoneTree/Segments/InMemory/MutableSegmentLoader.cs b/src/ZoneTree/Segments/InMemory/MutableSegmentLoader.cs
@@ -1,6 +1,7 @@
 using Tenray.ZoneTree.Exceptions;
 using Tenray.ZoneTree.Core;
 using Tenray.ZoneTree.Options;
+using Tenray.ZoneTree.WAL;
 
 namespace Tenray.ZoneTree.Segments.InMemory;
 
@@ -17,9 +18,10 @@ public sealed class MutableSegmentLoader<TKey, TValue>
     public IMutableSegment<TKey, TValue> LoadMutableSegment(
         long segmentId,
         long maximumOpIndex,
-        bool collectGarbage)
+        bool collectGarbage,
+        out IWriteAheadLog<TKey, TValue> wal)
     {
-        var wal = Options.WriteAheadLogProvider
+        wal = Options.WriteAheadLogProvider
             .GetOrCreateWAL(
                 segmentId,
                 ZoneTree<TKey, TValue>.SegmentWalCategory,