Removed rangeSize option from Native LSS

since the only reasonable option is 64. This simplifies code as well.

community/index/src/main/java/org/neo4j/index/gbptree/Layout.java

@@ -122,7 +122,9 @@ public interface Layout<KEY, VALUE> extends Comparator<KEY>
      *
      * @param cursor {@link PageCursor} to write into, at its current offset.
      */
-    void writeMetaData( PageCursor cursor );
+    default void writeMetaData( PageCursor cursor )
+    {   // no meta-data by default
+    }
 
     /**
      * Reads meta data specific to this layout instance from {@code cursor} at its current offset.
@@ -133,7 +135,9 @@ public interface Layout<KEY, VALUE> extends Comparator<KEY>
      *
      * @param cursor {@link PageCursor} to read from, at its current offset.
      */
-    void readMetaData( PageCursor cursor );
+    default void readMetaData( PageCursor cursor )
+    {   // no meta-data by default
+    }
 
     /**
      * Utility method for generating an {@link #identifier()}.

community/kernel/src/main/java/org/neo4j/kernel/impl/api/scan/NativeLabelScanStoreExtension.java

@@ -47,6 +47,6 @@ public NativeLabelScanStoreExtension()
     public Lifecycle newInstance( KernelContext context, Dependencies dependencies ) throws Throwable
     {
         return new LabelScanStoreProvider( new NativeLabelScanStore( dependencies.pageCache(),
-                context.storeDir(), Long.SIZE, new FullLabelStream( dependencies.indexStoreView() ) ), 0 );
+                context.storeDir(), new FullLabelStream( dependencies.indexStoreView() ) ), 0 );
     }
 }

community/kernel/src/main/java/org/neo4j/kernel/impl/index/labelscan/LabelScanKey.java

@@ -21,7 +21,7 @@
 
 /**
  * Keys in {@link LabelScanLayout}, each key consists of {@code labelId} and {@code nodeIdRange}, i.e.
- * {@code nodeId/rangeSize}, where each range is a small bit set of size {@code rangeSize}.
+ * {@code nodeId/rangeSize}, where each range is a small bit set of size {@link LabelScanValue#RANGE_SIZE}.
  */
 class LabelScanKey
 {

community/kernel/src/main/java/org/neo4j/kernel/impl/index/labelscan/LabelScanLayout.java

@@ -23,8 +23,6 @@
 import org.neo4j.index.gbptree.Layout;
 import org.neo4j.io.pagecache.PageCursor;
 
-import static java.lang.Long.bitCount;
-
 /**
  * {@link Layout} for {@link GBPTree} used by {@link NativeLabelScanStore}.
  *
@@ -34,8 +32,7 @@
  * </li>
  * <li>
  * Each value is a 64-bit bit set (a primitive {@code long}) where each set bit in it represents
- * a node with that label, such that {@code nodeId = nodeIdRange+bitOffset}. Range size (e.g. 64 bits)
- * is configurable on initial creation of the store, 8, 16, 32 or 64.
+ * a node with that label, such that {@code nodeId = nodeIdRange+bitOffset}. Range size is 64 bits.
  * </li>
  * </ul>
  */
@@ -51,26 +48,6 @@ class LabelScanLayout implements Layout<LabelScanKey,LabelScanValue>
      */
     private static final int KEY_SIZE = Integer.BYTES/*labelId*/ + 6/*idRange*/;
 
-    /**
-     * Size of each node id range, e.g. 8, 16, 32 or 64. This value is written at creation,
-     * otherwise verified against index meta data on open.
-     */
-    private final int rangeSize;
-
-    /**
-     * {@link #rangeSize}, as number of bytes (instead of number of bits).
-     */
-    private final int rangeSizeBytes;
-
-    LabelScanLayout( int rangeSize )
-    {
-        // asserts values are 8, 16, 32 or 64
-        assert bitCount( rangeSize ) == 1 && (rangeSize & ~0b1111000) == 0;
-
-        this.rangeSize = rangeSize;
-        this.rangeSizeBytes = rangeSize >>> 3;
-    }
-
     /**
      * Compares {@link LabelScanKey}, giving ascending order of {@code labelId} then {@code nodeIdRange}.
      */
@@ -110,7 +87,7 @@ public int keySize()
     @Override
     public int valueSize()
     {
-        return rangeSizeBytes;
+        return LabelScanValue.RANGE_SIZE_BYTES;
     }
 
     @Override
@@ -129,23 +106,7 @@ private static void put6ByteLong( PageCursor cursor, long value )
     @Override
     public void writeValue( PageCursor cursor, LabelScanValue value )
     {
-        switch ( rangeSize )
-        {
-        case 8:
-            cursor.putByte( (byte) value.bits );
-            break;
-        case 16:
-            cursor.putShort( (short) value.bits );
-            break;
-        case 32:
-            cursor.putInt( (int) value.bits );
-            break;
-        case 64:
-            cursor.putLong( value.bits );
-            break;
-        default:
-            throw new IllegalArgumentException( String.valueOf( rangeSize ) );
-        }
+        cursor.putLong( value.bits );
     }
 
     @Override
@@ -165,29 +126,13 @@ private static long get6ByteLong( PageCursor cursor )
     @Override
     public void readValue( PageCursor cursor, LabelScanValue into )
     {
-        switch ( rangeSize )
-        {
-        case 8:
-            into.bits = cursor.getByte() & 0xFF;
-            break;
-        case 16:
-            into.bits = cursor.getShort() & 0xFFFF;
-            break;
-        case 32:
-            into.bits = cursor.getInt() & 0xFFFFFFFFL;
-            break;
-        case 64:
-            into.bits = cursor.getLong();
-            break;
-        default:
-            throw new IllegalArgumentException( String.valueOf( rangeSize ) );
-        }
+        into.bits = cursor.getLong();
     }
 
     @Override
     public long identifier()
     {
-        return Layout.namedIdentifier( IDENTIFIER_NAME, rangeSize );
+        return Layout.namedIdentifier( IDENTIFIER_NAME, LabelScanValue.RANGE_SIZE );
     }
 
     @Override
@@ -201,27 +146,4 @@ public int minorVersion()
     {
         return 1;
     }
-
-    /**
-     * Writes node id range size to the index meta data. The range size cannot change.
-     */
-    @Override
-    public void writeMetaData( PageCursor cursor )
-    {
-        cursor.putInt( rangeSize );
-    }
-
-    /**
-     * Reads node id range size of the index.
-     */
-    @Override
-    public void readMetaData( PageCursor cursor )
-    {
-        int rangeSize = cursor.getInt();
-        if ( this.rangeSize != rangeSize )
-        {
-            throw new IllegalArgumentException( "A different range size " + this.rangeSize +
-                    " was specified when loading an index with actual range size " + rangeSize );
-        }
-    }
 }

community/kernel/src/main/java/org/neo4j/kernel/impl/index/labelscan/LabelScanValue.java

@@ -24,6 +24,9 @@
  */
 class LabelScanValue
 {
+    static final int RANGE_SIZE = Long.SIZE;
+    static final int RANGE_SIZE_BYTES = Long.BYTES;
+
     /**
      * Small bit set.
      */

community/kernel/src/main/java/org/neo4j/kernel/impl/index/labelscan/LabelScanValueIterator.java

@@ -35,11 +35,6 @@
  */
 class LabelScanValueIterator extends PrimitiveLongCollections.PrimitiveLongBaseIterator
 {
-    /**
-     * Size of nodeId ranges, i.e. how many node ids one {@link LabelScanValue} can hold at most.
-     */
-    private final int rangeSize;
-
     /**
      * {@link RawCursor} to lazily read new {@link LabelScanValue} from.
      */
@@ -65,9 +60,8 @@ class LabelScanValueIterator extends PrimitiveLongCollections.PrimitiveLongBaseI
      */
     private long prevRange = -1;
 
-    LabelScanValueIterator( int rangeSize, RawCursor<Hit<LabelScanKey,LabelScanValue>,IOException> cursor )
+    LabelScanValueIterator( RawCursor<Hit<LabelScanKey,LabelScanValue>,IOException> cursor )
     {
-        this.rangeSize = rangeSize;
         this.cursor = cursor;
     }
 
@@ -99,7 +93,7 @@ protected boolean fetchNext()
             }
 
             Hit<LabelScanKey,LabelScanValue> hit = cursor.get();
-            baseNodeId = hit.key().idRange * rangeSize;
+            baseNodeId = hit.key().idRange * LabelScanValue.RANGE_SIZE;
             bits = hit.value().bits;
 
             assert keysInOrder( hit.key() );

community/kernel/src/main/java/org/neo4j/kernel/impl/index/labelscan/NativeLabelScanReader.java

@@ -47,21 +47,15 @@ class NativeLabelScanReader implements LabelScanReader
      */
     private final Index<LabelScanKey,LabelScanValue> index;
 
-    /**
-     * Size of each nodeId range, i.e. how many potential node ids each {@link LabelScanValue} contains.
-     */
-    private final int rangeSize;
-
     /**
      * Currently open {@link RawCursor} from query methods below. Open cursors are closed when calling
      * new query methods or when {@link #close() closing} this reader.
      */
     private final Queue<RawCursor<Hit<LabelScanKey,LabelScanValue>,IOException>> openCursors;
 
-    NativeLabelScanReader( Index<LabelScanKey,LabelScanValue> index, int rangeSize )
+    NativeLabelScanReader( Index<LabelScanKey,LabelScanValue> index )
     {
         this.index = index;
-        this.rangeSize = rangeSize;
         this.openCursors = new LinkedList<>();
     }
 
@@ -96,7 +90,7 @@ public PrimitiveLongIterator nodesWithLabel( int labelId )
             throw new RuntimeException( e );
         }
 
-        return new LabelScanValueIterator( rangeSize, cursor );
+        return new LabelScanValueIterator( cursor );
     }
 
     @Override
@@ -123,7 +117,7 @@ private List<PrimitiveLongIterator> iteratorsForLabels( int[] labelIds )
             {
                 RawCursor<Hit<LabelScanKey,LabelScanValue>,IOException> cursor = seekerForLabel( labelId );
                 openCursors.offer( cursor );
-                iterators.add( new LabelScanValueIterator( rangeSize, cursor ) );
+                iterators.add( new LabelScanValueIterator( cursor ) );
             }
         }
         catch ( IOException e )

community/kernel/src/main/java/org/neo4j/kernel/impl/index/labelscan/NativeLabelScanStore.java

@@ -77,12 +77,6 @@ public class NativeLabelScanStore implements LabelScanStore
      */
     private final File storeFile;
 
-    /**
-     * Size of each node id range, e.g. 8, 16, 32 or 64. This value is written at creation,
-     * otherwise verified against index meta data on open.
-     */
-    private final int rangeSize;
-
     /**
      * Used in {@link #start()} if the store is empty, where this will provide all data for fully populating
      * this label scan store. This can be the case when changing label scan store provider on an existing database.
@@ -114,24 +108,23 @@ public class NativeLabelScanStore implements LabelScanStore
 
     private final NativeLabelScanWriter singleWriter;
 
-    public NativeLabelScanStore( PageCache pageCache, File storeDir, int rangeSize,
+    public NativeLabelScanStore( PageCache pageCache, File storeDir,
             FullStoreChangeStream fullStoreChangeStream )
     {
-        this( pageCache, storeDir, rangeSize, fullStoreChangeStream, 0/*means no opinion about page size*/ );
+        this( pageCache, storeDir, fullStoreChangeStream, 0/*means no opinion about page size*/ );
     }
 
     /*
      * Test access to be able to control page size.
      */
-    NativeLabelScanStore( PageCache pageCache, File storeDir, int rangeSize,
+    NativeLabelScanStore( PageCache pageCache, File storeDir,
             FullStoreChangeStream fullStoreChangeStream, int pageSize )
     {
         this.pageCache = pageCache;
         this.pageSize = pageSize;
         this.fullStoreChangeStream = fullStoreChangeStream;
         this.storeFile = new File( storeDir, DEFAULT_NAME + ".labelscanstore.db" );
-        this.rangeSize = rangeSize;
-        this.singleWriter = new NativeLabelScanWriter( rangeSize, 1_000 );
+        this.singleWriter = new NativeLabelScanWriter( 1_000 );
     }
 
     /**
@@ -143,7 +136,7 @@ public NativeLabelScanStore( PageCache pageCache, File storeDir, int rangeSize,
     @Override
     public LabelScanReader newReader()
     {
-        return new NativeLabelScanReader( index, rangeSize );
+        return new NativeLabelScanReader( index );
     }
 
     /**
@@ -226,7 +219,7 @@ public ResourceIterator<File> snapshotStoreFiles() throws IOException
     @Override
     public void init() throws IOException
     {
-        index = new GBPTree<>( pageCache, storeFile, new LabelScanLayout( rangeSize ), pageSize, NO_MONITOR );
+        index = new GBPTree<>( pageCache, storeFile, new LabelScanLayout(), pageSize, NO_MONITOR );
     }
 
     /**

community/kernel/src/main/java/org/neo4j/kernel/impl/index/labelscan/NativeLabelScanWriter.java

@@ -33,6 +33,8 @@
 import static java.lang.Long.min;
 import static java.lang.Math.toIntExact;
 
+import static org.neo4j.kernel.impl.index.labelscan.LabelScanValue.RANGE_SIZE;
+
 /**
  * {@link LabelScanWriter} for {@link NativeLabelScanStore}, or rather an {@link IndexWriter} for its
  * internal {@link GBPTree}.
@@ -84,12 +86,6 @@ class NativeLabelScanWriter implements LabelScanWriter
      */
     private final LabelScanValue value = new LabelScanValue();
 
-    /**
-     * Configured range size for this index. Range size is the size of each {@link LabelScanValue},
-     * i.e. how big each bit set range is, e.g. 8, 16, 32 or 64.
-     */
-    private final int rangeSize;
-
     /**
      * Batch currently building up as {@link #write(NodeLabelUpdate) updates} come in. Cursor for where
      * to place new updates is {@link #pendingUpdatesCursor}. Length of this queue is decided in constructor
@@ -120,9 +116,8 @@ class NativeLabelScanWriter implements LabelScanWriter
      */
     private long lowestLabelId;
 
-    NativeLabelScanWriter( int rangeSize, int batchSize )
+    NativeLabelScanWriter( int batchSize )
     {
-        this.rangeSize = rangeSize;
         this.pendingUpdates = new NodeLabelUpdate[batchSize];
     }
 
@@ -241,7 +236,7 @@ private void change( long currentLabelId, long nodeId, boolean add ) throws IOEx
             addition = add;
         }
 
-        value.set( toIntExact( nodeId % rangeSize ) );
+        value.set( toIntExact( nodeId % RANGE_SIZE ) );
     }
 
     private void flushPendingRange() throws IOException
@@ -256,9 +251,9 @@ private void flushPendingRange() throws IOException
         }
     }
 
-    private long rangeOf( long nodeId )
+    private static long rangeOf( long nodeId )
     {
-        return nodeId / rangeSize;
+        return nodeId / RANGE_SIZE;
     }
 
     /**

community/kernel/src/test/java/org/neo4j/kernel/impl/index/labelscan/NativeLabelScanReaderTest.java

@@ -55,16 +55,19 @@ public void shouldFindMultipleNodesInEachRange() throws Exception
                 null );
         when( index.seek( any( LabelScanKey.class ), any( LabelScanKey.class ) ) )
                 .thenReturn( cursor );
-        try ( NativeLabelScanReader reader = new NativeLabelScanReader( index, 16 ) )
+        try ( NativeLabelScanReader reader = new NativeLabelScanReader( index ) )
         {
             // WHEN
             PrimitiveLongIterator iterator = reader.nodesWithLabel( LABEL_ID );
 
             // THEN
             assertArrayEquals( new long[] {
+                    // base 0*64 = 0
                     1, 6, 7, 11, 15,
-                    19, 25,
-                    48, 53, 55, 61 },
+                    // base 1*64 = 64
+                    64 + 3, 64 + 9,
+                    // base 3*64 = 192
+                    192 + 0, 192 + 5, 192 + 7, 192 + 13 },
 
                     asArray( iterator ) );
         }