Cache various Enum.values() used in deserialization to avoid per-read array allocation

patch by Koo Taejin; reviewed by Dmitry Konstantinov, Stefan Miklosovic for CASSANDRA-21528

CHANGES.txt

@@ -1,4 +1,5 @@
 6.0-alpha2
+ * Cache various Enum.values() used in deserialization to avoid per-read array allocation (CASSANDRA-21528)
  * Fix Accord transaction error message when altering a table (CASSANDRA-20580)
  * Depend only on platform-specific Zstd JNI native libraries (CASSANDRA-21483)
  * Expose immediately-executed tasks in the queries virtual table (CASSANDRA-21471)

src/java/org/apache/cassandra/cql3/selection/Selector.java

@@ -96,12 +96,19 @@ public abstract class Selector
         SLICE_SELECTOR(ElementsSelector.SliceSelector.deserializer),
         VECTOR_SELECTOR(VectorSelector.deserializer);
 
+        private static final Kind[] VALUES = values();
+
         private final SelectorDeserializer deserializer;
 
         Kind(SelectorDeserializer deserializer)
         {
             this.deserializer = deserializer;
         }
+
+        public static Kind fromOrdinal(int ordinal)
+        {
+            return VALUES[ordinal];
+        }
     }
 
     /**
@@ -260,7 +267,7 @@ public abstract class Selector
 
         public Selector deserialize(DataInputPlus in, int version, TableMetadata metadata) throws IOException
         {
-            Kind kind = Kind.values()[in.readUnsignedByte()];
+            Kind kind = Kind.fromOrdinal(in.readUnsignedByte());
             return kind.deserializer.deserialize(in, version, metadata);
         }
 

src/java/org/apache/cassandra/db/ClusteringBoundOrBoundary.java

@@ -116,7 +116,7 @@ public interface ClusteringBoundOrBoundary<V> extends ClusteringPrefix<V>
 
         public ClusteringBoundOrBoundary<byte[]> deserialize(DataInputPlus in, int version, List<AbstractType<?>> types) throws IOException
         {
-            Kind kind = Kind.values()[in.readByte()];
+            Kind kind = Kind.fromOrdinal(in.readByte());
             return deserializeValues(in, kind, version, types);
         }
 

src/java/org/apache/cassandra/db/ClusteringPrefix.java

@@ -84,6 +84,8 @@ public interface ClusteringPrefix<V> extends IMeasurableMemory, Clusterable<V>
         SSTABLE_UPPER_BOUND          ( 4,  1, v -> ByteSource.GTGT_NEXT_COMPONENT);
         // @formatter:on
 
+        private static final Kind[] VALUES = values();
+
         private final int comparison;
 
         /**
@@ -101,6 +103,11 @@ public interface ClusteringPrefix<V> extends IMeasurableMemory, Clusterable<V>
             this.asByteComparable = asByteComparable;
         }
 
+        public static Kind fromOrdinal(int ordinal)
+        {
+            return VALUES[ordinal];
+        }
+
         /**
          * Compares the 2 provided kind.
          * <p>
@@ -476,7 +483,7 @@ public interface ClusteringPrefix<V> extends IMeasurableMemory, Clusterable<V>
 
         public void skip(DataInputPlus in, int version, List<AbstractType<?>> types) throws IOException
         {
-            Kind kind = Kind.values()[in.readByte()];
+            Kind kind = Kind.fromOrdinal(in.readByte());
             // We shouldn't serialize static clusterings
             assert kind != Kind.STATIC_CLUSTERING;
             if (kind == Kind.CLUSTERING)
@@ -487,7 +494,7 @@ public interface ClusteringPrefix<V> extends IMeasurableMemory, Clusterable<V>
 
         public ClusteringPrefix<byte[]> deserialize(DataInputPlus in, int version, List<AbstractType<?>> types) throws IOException
         {
-            Kind kind = Kind.values()[in.readByte()];
+            Kind kind = Kind.fromOrdinal(in.readByte());
             // We shouldn't serialize static clusterings
             assert kind != Kind.STATIC_CLUSTERING;
             if (kind == Kind.CLUSTERING)
@@ -657,7 +664,7 @@ public interface ClusteringPrefix<V> extends IMeasurableMemory, Clusterable<V>
                 throw new IOException("Corrupt flags value for clustering prefix (isStatic flag set): " + flags);
 
             this.nextIsRow = UnfilteredSerializer.kind(flags) == Unfiltered.Kind.ROW;
-            this.nextKind = nextIsRow ? Kind.CLUSTERING : ClusteringPrefix.Kind.values()[in.readByte()];
+            this.nextKind = nextIsRow ? Kind.CLUSTERING : Kind.fromOrdinal(in.readByte());
             this.nextSize = nextIsRow ? comparator.size() : in.readUnsignedShort();
             this.deserializedSize = 0;
 

src/java/org/apache/cassandra/db/ReadCommand.java

@@ -198,6 +198,8 @@ public abstract class ReadCommand extends AbstractReadQuery
         SINGLE_PARTITION (SinglePartitionReadCommand.selectionDeserializer, SinglePartitionReadCommand.accordSelectionDeserializer),
         PARTITION_RANGE  (PartitionRangeReadCommand.selectionDeserializer, ignore -> PartitionRangeReadCommand.selectionDeserializer);
 
+        private static final Kind[] VALUES = values();
+
         private final SelectionDeserializer selectionDeserializer;
         private final Function<Seekable, SelectionDeserializer> accordSelectionDeserializer;
 
@@ -206,6 +208,11 @@ public abstract class ReadCommand extends AbstractReadQuery
             this.selectionDeserializer = selectionDeserializer;
             this.accordSelectionDeserializer = accordSelectionDeserializer;
         }
+
+        public static Kind fromOrdinal(int ordinal)
+        {
+            return VALUES[ordinal];
+        }
     }
 
     protected ReadCommand(Epoch serializedAtEpoch,
@@ -1450,7 +1457,7 @@ public abstract class ReadCommand extends AbstractReadQuery
 
         public ReadCommand deserialize(DataInputPlus in, int version) throws IOException
         {
-            Kind kind = Kind.values()[in.readByte()];
+            Kind kind = Kind.fromOrdinal(in.readByte());
             int flags = in.readByte();
             // Shouldn't happen or it's a user error (see comment above) but
             // better complain loudly than doing the wrong thing.
@@ -1488,7 +1495,7 @@ public abstract class ReadCommand extends AbstractReadQuery
 
         public ReadCommand deserializeForAccord(Seekable key, TableMetadatas tables, DataInputPlus in, int version) throws IOException
         {
-            Kind kind = Kind.values()[in.readByte()];
+            Kind kind = Kind.fromOrdinal(in.readByte());
             int flags = in.readByte();
             if (isDigest(flags) || isForThrift(flags) || acceptsTransient(flags))
                 throw new IllegalStateException("Received an Accord command with a digest/thrift/transient flag set.");

src/java/org/apache/cassandra/db/aggregation/AggregationSpecification.java

@@ -65,7 +65,14 @@ public abstract class AggregationSpecification
      */
     public enum Kind
     {
-        AGGREGATE_EVERYTHING, AGGREGATE_BY_PK_PREFIX, AGGREGATE_BY_PK_PREFIX_WITH_SELECTOR
+        AGGREGATE_EVERYTHING, AGGREGATE_BY_PK_PREFIX, AGGREGATE_BY_PK_PREFIX_WITH_SELECTOR;
+
+        private static final Kind[] VALUES = values();
+
+        public static Kind fromOrdinal(int ordinal)
+        {
+            return VALUES[ordinal];
+        }
     }
 
     /**
@@ -253,7 +260,7 @@ public abstract class AggregationSpecification
 
         public AggregationSpecification deserialize(DataInputPlus in, int version, TableMetadata metadata) throws IOException
         {
-            Kind kind = Kind.values()[in.readUnsignedByte()];
+            Kind kind = Kind.fromOrdinal(in.readUnsignedByte());
             switch (kind)
             {
                 case AGGREGATE_EVERYTHING:

src/java/org/apache/cassandra/db/filter/AbstractClusteringIndexFilter.java

@@ -80,7 +80,7 @@ public abstract class AbstractClusteringIndexFilter implements ClusteringIndexFi
 
         public ClusteringIndexFilter deserialize(DataInputPlus in, int version, TableMetadata metadata) throws IOException
         {
-            Kind kind = Kind.values()[in.readUnsignedByte()];
+            Kind kind = Kind.fromOrdinal(in.readUnsignedByte());
             boolean reversed = in.readBoolean();
 
             return kind.deserializer.deserialize(in, version, metadata, reversed);

src/java/org/apache/cassandra/db/filter/ClusteringIndexFilter.java

@@ -46,12 +46,19 @@ public interface ClusteringIndexFilter
         SLICE (ClusteringIndexSliceFilter.deserializer),
         NAMES (ClusteringIndexNamesFilter.deserializer);
 
+        private static final Kind[] VALUES = values();
+
         protected final InternalDeserializer deserializer;
 
         private Kind(InternalDeserializer deserializer)
         {
             this.deserializer = deserializer;
         }
+
+        public static Kind fromOrdinal(int ordinal)
+        {
+            return VALUES[ordinal];
+        }
     }
 
     static interface InternalDeserializer

src/java/org/apache/cassandra/db/filter/ColumnSubselection.java

@@ -44,7 +44,17 @@ public abstract class ColumnSubselection implements Comparable<ColumnSubselectio
     public static final Serializer serializer = new Serializer();
 
     /* this enum is used in serialization; preserve order for compatibility */
-    private enum Kind { SLICE, ELEMENT }
+    private enum Kind
+    {
+        SLICE, ELEMENT;
+
+        private static final Kind[] VALUES = values();
+
+        static Kind fromOrdinal(int ordinal)
+        {
+            return VALUES[ordinal];
+        }
+    }
 
     protected final ColumnMetadata column;
 
@@ -229,7 +239,7 @@ public abstract class ColumnSubselection implements Comparable<ColumnSubselectio
                 }
             }
 
-            Kind kind = Kind.values()[in.readUnsignedByte()];
+            Kind kind = Kind.fromOrdinal(in.readUnsignedByte());
             switch (kind)
             {
                 case SLICE:

src/java/org/apache/cassandra/db/filter/DataLimits.java

@@ -102,7 +102,14 @@ public abstract class DataLimits
         /** @deprecated See CASSANDRA-16582 */
         @Deprecated(since = "4.0") SUPER_COLUMN_COUNTING_LIMIT, //Deprecated and unused in 4.0, stop publishing in 5.0, reclaim in 6.0
         CQL_GROUP_BY_LIMIT,
-        CQL_GROUP_BY_PAGING_LIMIT,
+        CQL_GROUP_BY_PAGING_LIMIT;
+
+        private static final Kind[] VALUES = values();
+
+        public static Kind fromOrdinal(int ordinal)
+        {
+            return VALUES[ordinal];
+        }
     }
 
     public static DataLimits cqlLimits(int cqlRowLimit)
@@ -1191,7 +1198,7 @@ public abstract class DataLimits
 
         public DataLimits deserialize(DataInputPlus in, int version, TableMetadata metadata) throws IOException
         {
-            Kind kind = Kind.values()[in.readUnsignedByte()];
+            Kind kind = Kind.fromOrdinal(in.readUnsignedByte());
             switch (kind)
             {
                 case CQL_LIMIT:

src/java/org/apache/cassandra/db/filter/RowFilter.java

@@ -493,7 +493,17 @@ public class RowFilter implements Iterable<RowFilter.Expression>
         // and this is why we have some UNUSEDX for values we don't use anymore
         // (we could clean those on a major protocol update, but it's not worth
         // the trouble for now)
-        protected enum Kind { SIMPLE, MAP_ELEMENT, UNUSED1, CUSTOM, USER }
+        protected enum Kind
+        {
+            SIMPLE, MAP_ELEMENT, UNUSED1, CUSTOM, USER;
+
+            private static final Kind[] VALUES = values();
+
+            static Kind fromOrdinal(int ordinal)
+            {
+                return VALUES[ordinal];
+            }
+        }
 
         protected abstract Kind kind();
         protected final ColumnMetadata column;
@@ -685,7 +695,7 @@ public class RowFilter implements Iterable<RowFilter.Expression>
 
             public Expression deserialize(DataInputPlus in, int version, TableMetadata metadata) throws IOException
             {
-                Kind kind = Kind.values()[in.readByte()];
+                Kind kind = Kind.fromOrdinal(in.readByte());
 
                 // custom expressions (3.0+ only) do not contain a column or operator, only a value
                 if (kind == Kind.CUSTOM)

src/java/org/apache/cassandra/io/sstable/ClusteringDescriptor.java

@@ -61,7 +61,7 @@ public class ClusteringDescriptor extends ResizableByteBuffer
 
     protected void loadClustering(RandomAccessReader dataReader, byte clusteringKind, int clusteringColumnsBound) throws IOException
     {
-        set(ClusteringPrefix.Kind.values()[clusteringKind], clusteringKind, clusteringColumnsBound);
+        set(ClusteringPrefix.Kind.fromOrdinal(clusteringKind), clusteringKind, clusteringColumnsBound);
         if (clusteringKind != STATIC_CLUSTERING_KIND)
             readUnfilteredClustering(dataReader, clusteringTypes, this.clusteringColumnsBound, this);
         else
@@ -103,7 +103,7 @@ public class ClusteringDescriptor extends ResizableByteBuffer
     }
 
     private void set(byte clusteringKindEncoded, int clusteringColumnsBound) {
-        set(ClusteringPrefix.Kind.values()[clusteringKindEncoded], clusteringKindEncoded, clusteringColumnsBound);
+        set(ClusteringPrefix.Kind.fromOrdinal(clusteringKindEncoded), clusteringKindEncoded, clusteringColumnsBound);
     }
 
     private void set(ClusteringPrefix.Kind clusteringKind, byte clusteringKindEncoded, int clusteringColumnsBound)

src/java/org/apache/cassandra/io/sstable/SSTableCursorWriter.java

@@ -513,7 +513,7 @@ public class SSTableCursorWriter implements AutoCloseable
     public void writeRangeTombstone(UnfilteredDescriptor rangeTombstone, boolean updateClusteringMetadata) throws IOException
     {
         int tombstoneKind = rangeTombstone.clusteringKindEncoded();
-        ClusteringPrefix.Kind kind = ClusteringPrefix.Kind.values()[tombstoneKind];
+        ClusteringPrefix.Kind kind = ClusteringPrefix.Kind.fromOrdinal(tombstoneKind);
         long unfilteredStartPosition = getPosition();
         /** See: {@link org.apache.cassandra.db.rows.UnfilteredSerializer#serialize */
         dataWriter.writeByte((byte)IS_MARKER);