Add Slice support to reduce_agg function

core/trino-main/src/main/java/io/trino/operator/aggregation/ReduceAggregationFunction.java

@@ -14,13 +14,16 @@
 package io.trino.operator.aggregation;
 
 import com.google.common.collect.ImmutableList;
+import io.airlift.slice.Slice;
 import io.trino.metadata.SqlAggregationFunction;
 import io.trino.operator.aggregation.state.GenericBooleanState;
 import io.trino.operator.aggregation.state.GenericBooleanStateSerializer;
 import io.trino.operator.aggregation.state.GenericDoubleState;
 import io.trino.operator.aggregation.state.GenericDoubleStateSerializer;
 import io.trino.operator.aggregation.state.GenericLongState;
 import io.trino.operator.aggregation.state.GenericLongStateSerializer;
+import io.trino.operator.aggregation.state.GenericSliceState;
+import io.trino.operator.aggregation.state.GenericSliceStateSerializer;
 import io.trino.operator.aggregation.state.StateCompiler;
 import io.trino.spi.TrinoException;
 import io.trino.spi.block.BlockBuilder;
@@ -51,14 +54,17 @@ public class ReduceAggregationFunction
     private static final MethodHandle LONG_STATE_INPUT_FUNCTION = methodHandle(ReduceAggregationFunction.class, "input", GenericLongState.class, Object.class, long.class, BinaryFunctionInterface.class, BinaryFunctionInterface.class);
     private static final MethodHandle DOUBLE_STATE_INPUT_FUNCTION = methodHandle(ReduceAggregationFunction.class, "input", GenericDoubleState.class, Object.class, double.class, BinaryFunctionInterface.class, BinaryFunctionInterface.class);
     private static final MethodHandle BOOLEAN_STATE_INPUT_FUNCTION = methodHandle(ReduceAggregationFunction.class, "input", GenericBooleanState.class, Object.class, boolean.class, BinaryFunctionInterface.class, BinaryFunctionInterface.class);
+    private static final MethodHandle SLICE_STATE_INPUT_FUNCTION = methodHandle(ReduceAggregationFunction.class, "input", GenericSliceState.class, Object.class, Slice.class, BinaryFunctionInterface.class, BinaryFunctionInterface.class);
 
     private static final MethodHandle LONG_STATE_COMBINE_FUNCTION = methodHandle(ReduceAggregationFunction.class, "combine", GenericLongState.class, GenericLongState.class, BinaryFunctionInterface.class, BinaryFunctionInterface.class);
     private static final MethodHandle DOUBLE_STATE_COMBINE_FUNCTION = methodHandle(ReduceAggregationFunction.class, "combine", GenericDoubleState.class, GenericDoubleState.class, BinaryFunctionInterface.class, BinaryFunctionInterface.class);
     private static final MethodHandle BOOLEAN_STATE_COMBINE_FUNCTION = methodHandle(ReduceAggregationFunction.class, "combine", GenericBooleanState.class, GenericBooleanState.class, BinaryFunctionInterface.class, BinaryFunctionInterface.class);
+    private static final MethodHandle SLICE_STATE_COMBINE_FUNCTION = methodHandle(ReduceAggregationFunction.class, "combine", GenericSliceState.class, GenericSliceState.class, BinaryFunctionInterface.class, BinaryFunctionInterface.class);
 
     private static final MethodHandle LONG_STATE_OUTPUT_FUNCTION = methodHandle(GenericLongState.class, "write", Type.class, GenericLongState.class, BlockBuilder.class);
     private static final MethodHandle DOUBLE_STATE_OUTPUT_FUNCTION = methodHandle(GenericDoubleState.class, "write", Type.class, GenericDoubleState.class, BlockBuilder.class);
     private static final MethodHandle BOOLEAN_STATE_OUTPUT_FUNCTION = methodHandle(GenericBooleanState.class, "write", Type.class, GenericBooleanState.class, BlockBuilder.class);
+    private static final MethodHandle SLICE_STATE_OUTPUT_FUNCTION = methodHandle(GenericSliceState.class, "write", Type.class, GenericSliceState.class, BlockBuilder.class);
 
     public ReduceAggregationFunction()
     {
@@ -122,7 +128,21 @@ public AggregationImplementation specialize(BoundSignature boundSignature)
                     .lambdaInterfaces(BinaryFunctionInterface.class, BinaryFunctionInterface.class)
                     .build();
         }
-        // State with Slice or Block as native container type is intentionally not supported yet,
+
+        if (stateType.getJavaType() == Slice.class) {
+            return AggregationImplementation.builder()
+                    .inputFunction(normalizeInputMethod(boundSignature, inputType, SLICE_STATE_INPUT_FUNCTION))
+                    .combineFunction(SLICE_STATE_COMBINE_FUNCTION)
+                    .outputFunction(SLICE_STATE_OUTPUT_FUNCTION.bindTo(stateType))
+                    .accumulatorStateDescriptor(
+                            GenericSliceState.class,
+                            new GenericSliceStateSerializer(stateType),
+                            StateCompiler.generateStateFactory(GenericSliceState.class))
+                    .lambdaInterfaces(BinaryFunctionInterface.class, BinaryFunctionInterface.class)
+                    .build();
+        }
+
+        // State with Block as native container type is intentionally not supported yet,
         // as it may result in excessive JVM memory usage of remembered set.
         // See JDK-8017163.
         throw new TrinoException(NOT_SUPPORTED, format("State type not supported for %s: %s", NAME, stateType.getDisplayName()));
@@ -162,6 +182,15 @@ public static void input(GenericBooleanState state, Object value, boolean initia
         state.setValue((boolean) inputFunction.apply(state.getValue(), value));
     }
 
+    public static void input(GenericSliceState state, Object value, Slice initialStateValue, BinaryFunctionInterface inputFunction, BinaryFunctionInterface combineFunction)
+    {
+        if (state.isNull()) {
+            state.setNull(false);
+            state.setValue(initialStateValue);
+        }
+        state.setValue((Slice) inputFunction.apply(state.getValue(), value));
+    }
+
     public static void combine(GenericLongState state, GenericLongState otherState, BinaryFunctionInterface inputFunction, BinaryFunctionInterface combineFunction)
     {
         if (state.isNull()) {
@@ -188,4 +217,13 @@ public static void combine(GenericBooleanState state, GenericBooleanState otherS
         }
         state.setValue((boolean) combineFunction.apply(state.getValue(), otherState.getValue()));
     }
+
+    public static void combine(GenericSliceState state, GenericSliceState otherState, BinaryFunctionInterface inputFunction, BinaryFunctionInterface combineFunction)
+    {
+        if (state.isNull()) {
+            state.set(otherState);
+            return;
+        }
+        state.setValue((Slice) combineFunction.apply(state.getValue(), otherState.getValue()));
+    }
 }

core/trino-main/src/main/java/io/trino/operator/aggregation/state/GenericSliceState.java

@@ -0,0 +1,50 @@
+/*
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package io.trino.operator.aggregation.state;
+
+import io.airlift.slice.Slice;
+import io.trino.spi.block.BlockBuilder;
+import io.trino.spi.function.AccumulatorState;
+import io.trino.spi.function.AccumulatorStateMetadata;
+import io.trino.spi.type.Type;
+
+@AccumulatorStateMetadata(stateSerializerClass = GenericSliceStateSerializer.class)
+public interface GenericSliceState
+        extends AccumulatorState
+{
+    Slice getValue();
+
+    void setValue(Slice value);
+
+    @InitialBooleanValue(true)
+    boolean isNull();
+
+    void setNull(boolean value);
+
+    default void set(GenericSliceState state)
+    {
+        setValue(state.getValue());
+        setNull(state.isNull());
+    }
+
+    static void write(Type type, GenericSliceState state, BlockBuilder out)
+    {
+        if (state.isNull()) {
+            out.appendNull();
+        }
+        else {
+            type.writeSlice(out, state.getValue());
+        }
+    }
+}

core/trino-main/src/main/java/io/trino/operator/aggregation/state/GenericSliceStateSerializer.java

@@ -0,0 +1,56 @@
+/*
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package io.trino.operator.aggregation.state;
+
+import io.trino.spi.block.Block;
+import io.trino.spi.block.BlockBuilder;
+import io.trino.spi.function.AccumulatorStateSerializer;
+import io.trino.spi.type.Type;
+
+import static java.util.Objects.requireNonNull;
+
+public class GenericSliceStateSerializer
+        implements AccumulatorStateSerializer<GenericSliceState>
+{
+    private final Type serializedType;
+
+    public GenericSliceStateSerializer(Type serializedType)
+    {
+        this.serializedType = requireNonNull(serializedType, "serializedType is null");
+    }
+
+    @Override
+    public Type getSerializedType()
+    {
+        return serializedType;
+    }
+
+    @Override
+    public void serialize(GenericSliceState state, BlockBuilder out)
+    {
+        if (state.isNull()) {
+            out.appendNull();
+        }
+        else {
+            serializedType.writeSlice(out, state.getValue());
+        }
+    }
+
+    @Override
+    public void deserialize(Block block, int index, GenericSliceState state)
+    {
+        state.setNull(false);
+        state.setValue(serializedType.getSlice(block, index));
+    }
+}

docs/src/main/sphinx/functions/aggregate.md

@@ -634,5 +634,5 @@ GROUP BY id;
 -- (2, 42)
 ```
 
-The state type must be a boolean, integer, floating-point, or date/time/interval.
+The state type must be a boolean, integer, floating-point, char, varchar or date/time/interval.
 :::

testing/trino-testing/src/main/java/io/trino/testing/AbstractTestEngineOnlyQueries.java

@@ -2219,6 +2219,11 @@ public void testReduceAgg()
                         "FROM (VALUES (1, CAST(5 AS DOUBLE)), (1, 6), (1, 7), (2, 8), (2, 9), (3, 10)) AS t(x, y) " +
                         "GROUP BY x",
                 "VALUES (1, CAST(5 AS DOUBLE) + 6 + 7), (2, 8 + 9), (3, 10)");
+        assertQuery(
+                "SELECT x, reduce_agg(y, '', (a, b) -> a || b, (a, b) -> a || b) " +
+                        "FROM (VALUES ('1', '5'), ('1', '6'), ('1', '7'), ('2', '8'), ('2', '9'), ('3', '10')) AS t(x, y) " +
+                        "GROUP BY x",
+                "VALUES ('1', '567'), ('2', '89'), ('3', '10')");
     }
 
     @Test