Refactor RunLengthEncodedBlock hash combination logic

trinodb · Nov 18, 2023 · f9690fc · f9690fc
1 parent 06eaf0f
commit f9690fc
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Showing 2 changed files with 25 additions and 15 deletions.
diff --git a/core/trino-main/src/main/java/io/trino/operator/FlatHashStrategyCompiler.java b/core/trino-main/src/main/java/io/trino/operator/FlatHashStrategyCompiler.java
@@ -443,16 +443,6 @@ private static MethodDefinition generateHashBlockVectorized(ClassDefinition defi
                 block,
                 position);
 
-        BytecodeExpression setHashExpression;
-        if (field.index() == 0) {
-            // hashes[index] = hash;
-            setHashExpression = hashes.setElement(index, hash);
-        }
-        else {
-            // hashes[index] = CombineHashFunction.getHash(hashes[index], hash);
-            setHashExpression = hashes.setElement(index, invokeStatic(CombineHashFunction.class, "getHash", long.class, hashes.getElement(index), hash));
-        }
-
         BytecodeBlock rleHandling = new BytecodeBlock()
                 .append(new IfStatement("hash = block.isNull(position) ? NULL_HASH_CODE : hash(block, position)")
                         .condition(block.invoke("isNull", boolean.class, position))
@@ -463,11 +453,18 @@ private static MethodDefinition generateHashBlockVectorized(ClassDefinition defi
             rleHandling.append(invokeStatic(Arrays.class, "fill", void.class, hashes, constantInt(0), length, hash));
         }
         else {
-            rleHandling.append(new ForLoop("for (int index = 0; index < length; index++) { hashes[index] = CombineHashFunction.getHash(hashes[index], hash); }")
-                    .initialize(index.set(constantInt(0)))
-                    .condition(lessThan(index, length))
-                    .update(index.increment())
-                    .body(setHashExpression));
+            // CombineHashFunction.combineAllHashesWithConstant(hashes, 0, length, hash)
+            rleHandling.append(invokeStatic(CombineHashFunction.class, "combineAllHashesWithConstant", void.class, hashes, constantInt(0), length, hash));
+        }
+
+        BytecodeExpression setHashExpression;
+        if (field.index() == 0) {
+            // hashes[index] = hash;
+            setHashExpression = hashes.setElement(index, hash);
+        }
+        else {
+            // hashes[index] = CombineHashFunction.getHash(hashes[index], hash);
+            setHashExpression = hashes.setElement(index, invokeStatic(CombineHashFunction.class, "getHash", long.class, hashes.getElement(index), hash));
         }
 
         BytecodeBlock computeHashLoop = new BytecodeBlock()

diff --git a/core/trino-main/src/main/java/io/trino/operator/scalar/CombineHashFunction.java b/core/trino-main/src/main/java/io/trino/operator/scalar/CombineHashFunction.java
@@ -13,10 +13,13 @@
  */
 package io.trino.operator.scalar;
 
+import io.trino.annotation.UsedByGeneratedCode;
 import io.trino.spi.function.ScalarFunction;
 import io.trino.spi.function.SqlType;
 import io.trino.spi.type.StandardTypes;
 
+import static java.util.Objects.checkFromToIndex;
+
 public final class CombineHashFunction
 {
     private CombineHashFunction() {}
@@ -27,4 +30,14 @@ public static long getHash(@SqlType(StandardTypes.BIGINT) long previousHashValue
     {
         return (31 * previousHashValue + value);
     }
+
+    @UsedByGeneratedCode
+    public static void combineAllHashesWithConstant(long[] hashes, int fromIndex, int toIndex, long value)
+    {
+        checkFromToIndex(fromIndex, toIndex, hashes.length);
+
+        for (int i = 0; i < toIndex; i++) {
+            hashes[i] = (31 * hashes[i]) + value;
+        }
+    }
 }