[BugFix] Fix wrong plan in max(count(distinct)) when enable lowcardin…

…ality Signed-off-by: stdpain <[email protected]>
StarRocks · Dec 2, 2024 · c1e812e · c1e812e
1 parent fe38253
commit c1e812e
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Showing 2 changed files with 8 additions and 2 deletions.
diff --git a/...e/src/main/java/com/starrocks/sql/optimizer/rule/tree/AddDecodeNodeForDictStringRule.java b/...e/src/main/java/com/starrocks/sql/optimizer/rule/tree/AddDecodeNodeForDictStringRule.java
@@ -665,7 +665,9 @@ private PhysicalHashAggregateOperator rewriteAggOperator(PhysicalHashAggregateOp
                 if (canApplyDictDecodeOpt) {
                     CallOperator oldCall = kv.getValue();
                     int columnId = kv.getValue().getUsedColumns().getFirstId();
-                    if (context.needRewriteMultiCountDistinctColumns.contains(columnId)) {
+                    final String fnName = kv.getValue().getFnName();
+                    if (context.needRewriteMultiCountDistinctColumns.contains(columnId)
+                            && fnName.equals(FunctionSet.MULTI_DISTINCT_COUNT)) {
                         // we only need rewrite TFunction
                         Type[] newTypes = new Type[] {ID_TYPE};
                         AggregateFunction newFunction =
@@ -682,7 +684,6 @@ private PhysicalHashAggregateOperator rewriteAggOperator(PhysicalHashAggregateOp
 
                         List<ScalarOperator> newArguments = Collections.singletonList(dictColumn);
                         Type[] newTypes = newArguments.stream().map(ScalarOperator::getType).toArray(Type[]::new);
-                        String fnName = kv.getValue().getFnName();
                         AggregateFunction newFunction =
                                 (AggregateFunction) Expr.getBuiltinFunction(kv.getValue().getFnName(), newTypes,
                                         Function.CompareMode.IS_NONSTRICT_SUPERTYPE_OF);

diff --git a/fe/fe-core/src/test/java/com/starrocks/sql/plan/LowCardinalityTest.java b/fe/fe-core/src/test/java/com/starrocks/sql/plan/LowCardinalityTest.java
@@ -395,6 +395,11 @@ public void testDecodeNodeRewriteMultiCountDistinct() throws Exception {
         plan = getFragmentPlan(sql);
         Assert.assertTrue(plan.contains(" multi_distinct_count(11: S_ADDRESS), " +
                 "multi_distinct_count(12: S_COMMENT)"));
+
+        sql = "select max(a) from (select count(distinct S_ADDRESS) a from supplier)t";
+        plan = getFragmentPlan(sql);
+        assertContains(plan, "multi_distinct_count(9: count)");
+
         connectContext.getSessionVariable().setNewPlanerAggStage(3);
         sql = "select max(S_ADDRESS), count(distinct S_ADDRESS) from supplier group by S_ADDRESS;";
         plan = getFragmentPlan(sql);