Size BlockBuilder appropriately in map_keys

Previously we allocated one row worth of space per byte of input
7mming7 · Dec 22, 2015 · 6ed858b · 6ed858b
1 parent e86b1fe
commit 6ed858b
Showing 1 changed file with 1 addition and 1 deletion.
diff --git a/presto-main/src/main/java/com/facebook/presto/operator/scalar/MapKeys.java b/presto-main/src/main/java/com/facebook/presto/operator/scalar/MapKeys.java
@@ -69,7 +69,7 @@ public ScalarFunctionImplementation specialize(Map<String, Type> types, int arit
 
     public static Block getKeys(Type keyType, Block block)
     {
-        BlockBuilder blockBuilder = keyType.createBlockBuilder(new BlockBuilderStatus(), block.getSizeInBytes());
+        BlockBuilder blockBuilder = keyType.createBlockBuilder(new BlockBuilderStatus(), block.getPositionCount() / 2);
         for (int i = 0; i < block.getPositionCount(); i += 2) {
             keyType.appendTo(block, i, blockBuilder);
         }