Check for Unsupported Aggregation with Distinct when useApproxCountDistinct is enabled

sql/src/main/java/org/apache/druid/sql/calcite/aggregation/ApproxCountDistinctSqlAggregator.java

@@ -83,6 +83,7 @@ public Aggregation toDruidAggregation(
     );
   }
 
+  @NativelySupportsDistinct
   private static class ApproxCountDistinctSqlAggFunction extends SqlAggFunction
   {
     ApproxCountDistinctSqlAggFunction()

sql/src/main/java/org/apache/druid/sql/calcite/aggregation/NativelySupportsDistinct.java

@@ -0,0 +1,36 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you 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 org.apache.druid.sql.calcite.aggregation;
+
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+/**
+ * This annotation is to distinguish {@link org.apache.calcite.sql.SqlAggFunction}
+ * which supports the distinct aggregation natively
+ */
+@Retention(RetentionPolicy.RUNTIME)
+@Target({ElementType.TYPE})
+public @interface NativelySupportsDistinct
+{
+
+}

sql/src/main/java/org/apache/druid/sql/calcite/aggregation/builtin/ArrayConcatSqlAggregator.java

@@ -39,6 +39,7 @@
 import org.apache.druid.segment.VirtualColumn;
 import org.apache.druid.segment.column.ColumnType;
 import org.apache.druid.sql.calcite.aggregation.Aggregation;
+import org.apache.druid.sql.calcite.aggregation.NativelySupportsDistinct;
 import org.apache.druid.sql.calcite.aggregation.SqlAggregator;
 import org.apache.druid.sql.calcite.expression.DruidExpression;
 import org.apache.druid.sql.calcite.expression.Expressions;
@@ -142,6 +143,7 @@ public Aggregation toDruidAggregation(
     }
   }
 
+  @NativelySupportsDistinct
   private static class ArrayConcatAggFunction extends SqlAggFunction
   {
     ArrayConcatAggFunction()

sql/src/main/java/org/apache/druid/sql/calcite/aggregation/builtin/ArraySqlAggregator.java

@@ -41,6 +41,7 @@
 import org.apache.druid.query.aggregation.ExpressionLambdaAggregatorFactory;
 import org.apache.druid.segment.column.ColumnType;
 import org.apache.druid.sql.calcite.aggregation.Aggregation;
+import org.apache.druid.sql.calcite.aggregation.NativelySupportsDistinct;
 import org.apache.druid.sql.calcite.aggregation.SqlAggregator;
 import org.apache.druid.sql.calcite.expression.DruidExpression;
 import org.apache.druid.sql.calcite.expression.Expressions;
@@ -165,6 +166,7 @@ public RelDataType inferReturnType(SqlOperatorBinding sqlOperatorBinding)
     }
   }
 
+  @NativelySupportsDistinct
   private static class ArrayAggFunction extends SqlAggFunction
   {
     private static final ArrayAggReturnTypeInference RETURN_TYPE_INFERENCE = new ArrayAggReturnTypeInference();

sql/src/main/java/org/apache/druid/sql/calcite/aggregation/builtin/StringSqlAggregator.java

@@ -47,6 +47,7 @@
 import org.apache.druid.query.filter.SelectorDimFilter;
 import org.apache.druid.segment.column.ColumnType;
 import org.apache.druid.sql.calcite.aggregation.Aggregation;
+import org.apache.druid.sql.calcite.aggregation.NativelySupportsDistinct;
 import org.apache.druid.sql.calcite.aggregation.SqlAggregator;
 import org.apache.druid.sql.calcite.expression.DruidExpression;
 import org.apache.druid.sql.calcite.expression.Expressions;
@@ -226,6 +227,7 @@ public RelDataType inferReturnType(SqlOperatorBinding sqlOperatorBinding)
     }
   }
 
+  @NativelySupportsDistinct
   private static class StringAggFunction extends SqlAggFunction
   {
     private static final StringAggReturnTypeInference RETURN_TYPE_INFERENCE = new StringAggReturnTypeInference();

sql/src/main/java/org/apache/druid/sql/calcite/planner/DruidSqlValidator.java

@@ -28,6 +28,7 @@
 import org.apache.calcite.rel.type.RelRecordType;
 import org.apache.calcite.runtime.CalciteContextException;
 import org.apache.calcite.runtime.CalciteException;
+import org.apache.calcite.sql.SqlAggFunction;
 import org.apache.calcite.sql.SqlCall;
 import org.apache.calcite.sql.SqlIdentifier;
 import org.apache.calcite.sql.SqlInsert;
@@ -36,6 +37,7 @@
 import org.apache.calcite.sql.SqlNodeList;
 import org.apache.calcite.sql.SqlOperatorTable;
 import org.apache.calcite.sql.SqlSelect;
+import org.apache.calcite.sql.SqlSelectKeyword;
 import org.apache.calcite.sql.SqlUpdate;
 import org.apache.calcite.sql.SqlUtil;
 import org.apache.calcite.sql.SqlWindow;
@@ -64,6 +66,7 @@
 import org.apache.druid.segment.column.ColumnType;
 import org.apache.druid.segment.column.Types;
 import org.apache.druid.segment.column.ValueType;
+import org.apache.druid.sql.calcite.aggregation.NativelySupportsDistinct;
 import org.apache.druid.sql.calcite.expression.builtin.ScalarInArrayOperatorConversion;
 import org.apache.druid.sql.calcite.parser.DruidSqlIngest;
 import org.apache.druid.sql.calcite.parser.DruidSqlInsert;
@@ -755,8 +758,10 @@ public void validateCall(SqlCall call, SqlValidatorScope scope)
         throw buildCalciteContextException(
             StringUtils.format(
                 "The query contains window functions; To run these window functions, specify [%s] in query context.",
-                PlannerContext.CTX_ENABLE_WINDOW_FNS),
-            call);
+                PlannerContext.CTX_ENABLE_WINDOW_FNS
+            ),
+            call
+        );
       }
     }
     if (call.getKind() == SqlKind.NULLS_FIRST) {
@@ -771,6 +776,19 @@ public void validateCall(SqlCall call, SqlValidatorScope scope)
         throw buildCalciteContextException("ASCENDING ordering with NULLS LAST is not supported!", call);
       }
     }
+    if (plannerContext.getPlannerConfig().isUseApproximateCountDistinct() && isSqlCallDistinct(call)) {
+      if (call.getOperator().getKind() != SqlKind.COUNT && call.getOperator() instanceof SqlAggFunction) {
+        if (!call.getOperator().getClass().isAnnotationPresent(NativelySupportsDistinct.class)) {
+          throw buildCalciteContextException(
+              StringUtils.format(
+                  "Aggregation [%s] with DISTINCT is not supported when useApproximateCountDistinct is enabled. Run with disabling it.",
+                  call.getOperator().getName()
+              ),
+              call
+          );
+        }
+      }
+    }
     super.validateCall(call, scope);
   }
 
@@ -857,4 +875,11 @@ private SqlNode getSqlNodeFor(SqlInsert insert, int idx)
     }
     return src;
   }
+
+  private boolean isSqlCallDistinct(@Nullable SqlCall call)
+  {
+    return call != null
+           && call.getFunctionQuantifier() != null
+           && call.getFunctionQuantifier().getValue() == SqlSelectKeyword.DISTINCT;
+  }
 }

sql/src/main/java/org/apache/druid/sql/calcite/rule/GroupByRules.java

@@ -22,11 +22,13 @@
 import org.apache.calcite.rel.core.AggregateCall;
 import org.apache.calcite.rex.RexBuilder;
 import org.apache.calcite.rex.RexNode;
+import org.apache.calcite.sql.SqlKind;
 import org.apache.druid.query.aggregation.AggregatorFactory;
 import org.apache.druid.query.aggregation.FilteredAggregatorFactory;
 import org.apache.druid.query.filter.DimFilter;
 import org.apache.druid.segment.column.RowSignature;
 import org.apache.druid.sql.calcite.aggregation.Aggregation;
+import org.apache.druid.sql.calcite.aggregation.NativelySupportsDistinct;
 import org.apache.druid.sql.calcite.aggregation.SqlAggregator;
 import org.apache.druid.sql.calcite.expression.Expressions;
 import org.apache.druid.sql.calcite.filtration.Filtration;
@@ -69,6 +71,16 @@ public static Aggregation translateAggregateCall(
       return null;
     }
 
+    if (call.isDistinct() && call.getAggregation().getKind() != SqlKind.COUNT) {
+      if (!call.getAggregation().getClass().isAnnotationPresent(NativelySupportsDistinct.class)) {
+        plannerContext.setPlanningError(
+            "Aggregation [%s] with DISTINCT is not supported when useApproximateCountDistinct is enabled. Run with disabling it.",
+            call.getAggregation().getName()
+        );
+        return null;
+      }
+    }
+
     final DimFilter filter;
 
     if (call.filterArg >= 0) {

sql/src/test/java/org/apache/druid/sql/calcite/CalciteQueryTest.java

@@ -15516,6 +15516,20 @@ public void testWindowingErrorWithoutFeatureFlag()
     assertThat(e, invalidSqlIs("The query contains window functions; To run these window functions, specify [enableWindowing] in query context. (line [1], column [13])"));
   }
 
+  @Test
+  public void testDistinctSumNotSupportedWithApproximation()
+  {
+    DruidException e = assertThrows(
+        DruidException.class,
+        () -> testBuilder()
+            .queryContext(ImmutableMap.of(PlannerConfig.CTX_KEY_USE_APPROXIMATE_COUNT_DISTINCT, true))
+            .sql("SELECT sum(distinct m1) from druid.foo")
+            .run()
+    );
+
+    assertThat(e, invalidSqlContains("Aggregation [SUM] with DISTINCT is not supported"));
+  }
+
   @Test
   public void testUnSupportedNullsFirst()
   {

sql/src/test/java/org/apache/druid/sql/calcite/DrillWindowQueryTest.java

@@ -4426,7 +4426,7 @@ public void test_last_val_lastValFn_39()
     windowQueryTest();
   }
 
-  @NotYetSupported(Modes.NOT_ENOUGH_RULES)
+  @NotYetSupported(Modes.DISTINCT_AGGREGATE_NOT_SUPPORTED)
   @DrillTest("nestedAggs/emtyOvrCls_7")
   @Test
   public void test_nestedAggs_emtyOvrCls_7()
@@ -7274,7 +7274,7 @@ public void test_nestedAggs_emtyOvrCls_13()
     windowQueryTest();
   }
 
-  @NotYetSupported(Modes.RESULT_MISMATCH)
+  @NotYetSupported(Modes.DISTINCT_AGGREGATE_NOT_SUPPORTED)
   @DrillTest("nestedAggs/emtyOvrCls_8")
   @Test
   public void test_nestedAggs_emtyOvrCls_8()

sql/src/test/java/org/apache/druid/sql/calcite/NotYetSupported.java

@@ -77,7 +77,7 @@
   enum Modes
   {
     // @formatter:off
-    NOT_ENOUGH_RULES(DruidException.class, "not enough rules"),
+    DISTINCT_AGGREGATE_NOT_SUPPORTED(DruidException.class, "DISTINCT is not supported"),
     ERROR_HANDLING(AssertionError.class, "targetPersona: is <[A-Z]+> and category: is <[A-Z_]+> and errorCode: is"),
     EXPRESSION_NOT_GROUPED(DruidException.class, "Expression '[a-z]+' is not being grouped"),
     NULLS_FIRST_LAST(DruidException.class, "NULLS (FIRST|LAST)"),