Minor optimizations

patch by slebresne; reviewed by blambov for CASSANDRA-10410

The patch includes the 3 minor optimizations desribed below:
1) Faster copy in CompositeType.build(). We call CompositeType.build()
   relatively often when a table has a composite partition key. When
   copying source buffers into the composite result in that method, we
   can use our existing ByteBuffer.arrayCopy() method which is supposed
   to be faster since it uses FastByteOperations and saves the
   duplication of the buffer to copy
2) Faster UUID->ByteBuffer. We convert UUID to their ByteBuffer
    representation in a few places and do that by converting the UUID to
    a byte[] and then wrapping it. But our convertion of UUID to byte[]
    writes the 2 long the UUID is composed of byte by byte, while for a
    ByteBuffer we can easily just "put" both long. So the patch
    introduces a specific method to do that. That's arguably cleaner
    anyway.
3) Memoize hash value for DataResource. Every request does a hash map
   lookup on a DataResource (for validating access rights) which imply
   calling DataResource.hashCode(). Currently that uses
   Objects.hashCode(), which is a varargs methods and allocate an array
   (which, according to MissionControl seems to not be stack allocated).
   The patch does 2 things: it computes the hash only once in the ctor
   and it stores the DataResource for each table in the CFMetaData and
   uses that when checking access permissions for SelectStatement and
   ModificationStatement (the 2 statements where performance matters).
   The 2nd point also saves some unecessary test that the table exists
   when we actually know it does.

src/java/org/apache/cassandra/auth/DataResource.java

@@ -54,31 +54,22 @@ public class DataResource implements IResource
                                                                                             Permission.MODIFY,
                                                                                             Permission.AUTHORIZE);
     private static final String ROOT_NAME = "data";
-    private static final DataResource ROOT_RESOURCE = new DataResource();
+    private static final DataResource ROOT_RESOURCE = new DataResource(Level.ROOT, null, null);
 
     private final Level level;
     private final String keyspace;
     private final String table;
 
-    private DataResource()
-    {
-        level = Level.ROOT;
-        keyspace = null;
-        table = null;
-    }
+    // memoized hashcode since DataRessource is immutable and used in hashmaps often
+    private final transient int hash;
 
-    private DataResource(String keyspace)
+    private DataResource(Level level, String keyspace, String table)
     {
-        level = Level.KEYSPACE;
-        this.keyspace = keyspace;
-        table = null;
-    }
-
-    private DataResource(String keyspace, String table)
-    {
-        level = Level.TABLE;
+        this.level = level;
         this.keyspace = keyspace;
         this.table = table;
+
+        this.hash = Objects.hashCode(level, keyspace, table);
     }
 
     /**
@@ -97,7 +88,7 @@ public class DataResource implements IResource
      */
     public static DataResource keyspace(String keyspace)
     {
-        return new DataResource(keyspace);
+        return new DataResource(Level.KEYSPACE, keyspace, null);
     }
 
     /**
@@ -109,7 +100,7 @@ public class DataResource implements IResource
      */
     public static DataResource table(String keyspace, String table)
     {
-        return new DataResource(keyspace, table);
+        return new DataResource(Level.TABLE, keyspace, table);
     }
 
     /**
@@ -272,6 +263,6 @@ public class DataResource implements IResource
     @Override
     public int hashCode()
     {
-        return Objects.hashCode(level, keyspace, table);
+        return hash;
     }
 }

src/java/org/apache/cassandra/config/CFMetaData.java

@@ -38,6 +38,7 @@ import org.apache.commons.lang3.builder.ToStringBuilder;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
+import org.apache.cassandra.auth.DataResource;
 import org.apache.cassandra.cql3.ColumnIdentifier;
 import org.apache.cassandra.cql3.QueryProcessor;
 import org.apache.cassandra.cql3.statements.CFStatement;
@@ -118,6 +119,8 @@ public final class CFMetaData
     // for those tables in practice).
     private volatile ColumnDefinition compactValueColumn;
 
+    public final DataResource resource;
+
     /*
      * All of these methods will go away once CFMetaData becomes completely immutable.
      */
@@ -288,6 +291,7 @@ public final class CFMetaData
         this.partitionColumns = partitionColumns;
 
         this.serializers = new Serializers(this);
+        this.resource = DataResource.table(ksName, cfName);
         rebuild();
     }
 

src/java/org/apache/cassandra/cql3/functions/TimeFcts.java

@@ -67,7 +67,7 @@ public abstract class TimeFcts
             if (bb == null)
                 return null;
 
-            return ByteBuffer.wrap(UUIDGen.decompose(UUIDGen.minTimeUUID(TimestampType.instance.compose(bb).getTime())));
+            return UUIDGen.toByteBuffer(UUIDGen.minTimeUUID(TimestampType.instance.compose(bb).getTime()));
         }
     };
 
@@ -79,7 +79,7 @@ public abstract class TimeFcts
             if (bb == null)
                 return null;
 
-            return ByteBuffer.wrap(UUIDGen.decompose(UUIDGen.maxTimeUUID(TimestampType.instance.compose(bb).getTime())));
+            return UUIDGen.toByteBuffer(UUIDGen.maxTimeUUID(TimestampType.instance.compose(bb).getTime()));
         }
     };
 

src/java/org/apache/cassandra/cql3/statements/ModificationStatement.java

@@ -193,21 +193,21 @@ public abstract class ModificationStatement implements CQLStatement
 
     public void checkAccess(ClientState state) throws InvalidRequestException, UnauthorizedException
     {
-        state.hasColumnFamilyAccess(keyspace(), columnFamily(), Permission.MODIFY);
+        state.hasColumnFamilyAccess(cfm, Permission.MODIFY);
 
         // CAS updates can be used to simulate a SELECT query, so should require Permission.SELECT as well.
         if (hasConditions())
-            state.hasColumnFamilyAccess(keyspace(), columnFamily(), Permission.SELECT);
+            state.hasColumnFamilyAccess(cfm, Permission.SELECT);
 
         // MV updates need to get the current state from the table, and might update the views
         // Require Permission.SELECT on the base table, and Permission.MODIFY on the views
         Iterator<ViewDefinition> views = View.findAll(keyspace(), columnFamily()).iterator();
         if (views.hasNext())
         {
-            state.hasColumnFamilyAccess(keyspace(), columnFamily(), Permission.SELECT);
+            state.hasColumnFamilyAccess(cfm, Permission.SELECT);
             do
             {
-                state.hasColumnFamilyAccess(keyspace(), views.next().viewName, Permission.MODIFY);
+                state.hasColumnFamilyAccess(views.next().metadata, Permission.MODIFY);
             } while (views.hasNext());
         }
 

src/java/org/apache/cassandra/cql3/statements/SelectStatement.java

@@ -178,11 +178,11 @@ public class SelectStatement implements CQLStatement
         {
             CFMetaData baseTable = View.findBaseTable(keyspace(), columnFamily());
             if (baseTable != null)
-                state.hasColumnFamilyAccess(keyspace(), baseTable.cfName, Permission.SELECT);
+                state.hasColumnFamilyAccess(baseTable, Permission.SELECT);
         }
         else
         {
-            state.hasColumnFamilyAccess(keyspace(), columnFamily(), Permission.SELECT);
+            state.hasColumnFamilyAccess(cfm, Permission.SELECT);
         }
 
         for (Function function : getFunctions())

src/java/org/apache/cassandra/db/marshal/CompositeType.java

@@ -391,7 +391,9 @@ public class CompositeType extends AbstractCompositeType
         for (ByteBuffer bb : buffers)
         {
             ByteBufferUtil.writeShortLength(out, bb.remaining());
-            out.put(bb.duplicate());
+            int toCopy = bb.remaining();
+            ByteBufferUtil.arrayCopy(bb, bb.position(), out, out.position(), toCopy);
+            out.position(out.position() + toCopy);
             out.put((byte) 0);
         }
         out.flip();

src/java/org/apache/cassandra/db/marshal/UUIDType.java

@@ -140,7 +140,7 @@ public class UUIDType extends AbstractType<UUID>
         {
             try
             {
-                return ByteBuffer.wrap(UUIDGen.decompose(UUID.fromString(source)));
+                return UUIDGen.toByteBuffer(UUID.fromString(source));
             }
             catch (IllegalArgumentException e)
             {

src/java/org/apache/cassandra/serializers/UUIDSerializer.java

@@ -34,7 +34,7 @@ public class UUIDSerializer implements TypeSerializer<UUID>
 
     public ByteBuffer serialize(UUID value)
     {
-        return value == null ? ByteBufferUtil.EMPTY_BYTE_BUFFER : ByteBuffer.wrap(UUIDGen.decompose(value));
+        return value == null ? ByteBufferUtil.EMPTY_BYTE_BUFFER : UUIDGen.toByteBuffer(value);
     }
 
     public void validate(ByteBuffer bytes) throws MarshalException

src/java/org/apache/cassandra/service/ClientState.java

@@ -29,6 +29,7 @@ import org.slf4j.LoggerFactory;
 
 import org.apache.cassandra.auth.*;
 import org.apache.cassandra.config.Config;
+import org.apache.cassandra.config.CFMetaData;
 import org.apache.cassandra.config.DatabaseDescriptor;
 import org.apache.cassandra.config.Schema;
 import org.apache.cassandra.cql3.QueryHandler;
@@ -249,6 +250,12 @@ public class ClientState
         hasAccess(keyspace, perm, DataResource.table(keyspace, columnFamily));
     }
 
+    public void hasColumnFamilyAccess(CFMetaData cfm, Permission perm)
+    throws UnauthorizedException, InvalidRequestException
+    {
+        hasAccess(cfm.ksName, perm, cfm.resource);
+    }
+
     private void hasAccess(String keyspace, Permission perm, DataResource resource)
     throws UnauthorizedException, InvalidRequestException
     {

src/java/org/apache/cassandra/utils/UUIDGen.java

@@ -106,6 +106,15 @@ public class UUIDGen
         return new UUID(raw.getLong(raw.position()), raw.getLong(raw.position() + 8));
     }
 
+    public static ByteBuffer toByteBuffer(UUID uuid)
+    {
+        ByteBuffer buffer = ByteBuffer.allocate(16);
+        buffer.putLong(uuid.getMostSignificantBits());
+        buffer.putLong(uuid.getLeastSignificantBits());
+        buffer.flip();
+        return buffer;
+    }
+
     /** decomposes a uuid into raw bytes. */
     public static byte[] decompose(UUID uuid)
     {

test/unit/org/apache/cassandra/utils/UUIDTests.java

@@ -48,7 +48,6 @@ public class UUIDTests
         assert one.timestamp() < two.timestamp();
     }
 
-
     @Test
     public void testDecomposeAndRaw()
     {
@@ -58,6 +57,15 @@ public class UUIDTests
         assert a.equals(b);
     }
 
+    @Test
+    public void testToFromByteBuffer()
+    {
+        UUID a = UUIDGen.getTimeUUID();
+        ByteBuffer bb = UUIDGen.toByteBuffer(a);
+        UUID b = UUIDGen.getUUID(bb);
+        assert a.equals(b);
+    }
+
     @Test
     public void testTimeUUIDType()
     {