[CALCITE-4239] RelMdUniqueKeys returns wrong unique keys for Aggregat…

…e with grouping sets
apache · Sep 14, 2020 · 1ae20f3 · 1ae20f3
1 parent 99c0fef
commit 1ae20f3
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Showing 3 changed files with 21 additions and 6 deletions.
diff --git a/core/src/main/java/org/apache/calcite/rel/metadata/RelMdColumnUniqueness.java b/core/src/main/java/org/apache/calcite/rel/metadata/RelMdColumnUniqueness.java
@@ -348,10 +348,13 @@ public Boolean areColumnsUnique(Join rel, RelMetadataQuery mq,
 
   public Boolean areColumnsUnique(Aggregate rel, RelMetadataQuery mq,
       ImmutableBitSet columns, boolean ignoreNulls) {
-    columns = decorateWithConstantColumnsFromPredicates(columns, rel, mq);
-    // group by keys form a unique key
-    ImmutableBitSet groupKey = ImmutableBitSet.range(rel.getGroupCount());
-    return columns.contains(groupKey);
+    if (Aggregate.isSimple(rel) || ignoreNulls) {
+      columns = decorateWithConstantColumnsFromPredicates(columns, rel, mq);
+      // group by keys form a unique key
+      ImmutableBitSet groupKey = ImmutableBitSet.range(rel.getGroupCount());
+      return columns.contains(groupKey);
+    }
+    return null;
   }
 
   public Boolean areColumnsUnique(Values rel, RelMetadataQuery mq,

diff --git a/core/src/main/java/org/apache/calcite/rel/metadata/RelMdUniqueKeys.java b/core/src/main/java/org/apache/calcite/rel/metadata/RelMdUniqueKeys.java
@@ -246,8 +246,14 @@ public Set<ImmutableBitSet> getUniqueKeys(Join rel, RelMetadataQuery mq,
 
   public Set<ImmutableBitSet> getUniqueKeys(Aggregate rel, RelMetadataQuery mq,
       boolean ignoreNulls) {
-    // group by keys form a unique key
-    return ImmutableSet.of(rel.getGroupSet());
+    if (Aggregate.isSimple(rel) || ignoreNulls) {
+      // group by keys form a unique key
+      return ImmutableSet.of(rel.getGroupSet());
+    } else {
+      // If the aggregate has grouping sets, all group by keys might be null which means group by
+      // keys do not form a unique key.
+      return ImmutableSet.of();
+    }
   }
 
   public Set<ImmutableBitSet> getUniqueKeys(Union rel, RelMetadataQuery mq,

diff --git a/core/src/test/java/org/apache/calcite/test/RelMetadataTest.java b/core/src/test/java/org/apache/calcite/test/RelMetadataTest.java
@@ -1198,6 +1198,12 @@ private void checkColumnUniquenessForFilterWithConstantColumns(String sql) {
         ImmutableSet.of(ImmutableBitSet.of(0)));
   }
 
+  @Test void testGroupingSets() {
+    checkGetUniqueKeys("select deptno, sal, count(*) from emp\n"
+            + "group by GROUPING SETS (deptno, sal)",
+        ImmutableSet.of());
+  }
+
   @Test void testUnion() {
     checkGetUniqueKeys("select deptno from emp\n"
         + "union\n"