PHOENIX-3158 COUNT(DISTINCT) may return null instead of 0 after PHOENIX-258.
diff --git a/phoenix-core/src/it/java/org/apache/phoenix/end2end/DistinctPrefixFilterIT.java b/phoenix-core/src/it/java/org/apache/phoenix/end2end/DistinctPrefixFilterIT.java
index 1a0e4e1..e8e9e07 100644
--- a/phoenix-core/src/it/java/org/apache/phoenix/end2end/DistinctPrefixFilterIT.java
+++ b/phoenix-core/src/it/java/org/apache/phoenix/end2end/DistinctPrefixFilterIT.java
@@ -290,6 +290,8 @@
testCount("SELECT %s COUNT(DISTINCT col1) FROM " + testTable, -1);
testCount("SELECT %s COUNT(DISTINCT col2) FROM " + testTable, -1);
+
+ testCount("SELECT %s COUNT(DISTINCT prefix1) FROM " + testTable + " WHERE col1 < 0", -1);
}
@Test
diff --git a/phoenix-core/src/main/java/org/apache/phoenix/execute/AggregatePlan.java b/phoenix-core/src/main/java/org/apache/phoenix/execute/AggregatePlan.java
index 136379d..00d478a 100644
--- a/phoenix-core/src/main/java/org/apache/phoenix/execute/AggregatePlan.java
+++ b/phoenix-core/src/main/java/org/apache/phoenix/execute/AggregatePlan.java
@@ -223,7 +223,7 @@
AggregatingResultIterator aggResultIterator;
// No need to merge sort for ungrouped aggregation
- if (groupBy.isEmpty()) {
+ if (groupBy.isEmpty() || groupBy.isUngroupedAggregate()) {
aggResultIterator = new UngroupedAggregatingResultIterator(new ConcatResultIterator(iterators), aggregators);
// If salted or local index we still need a merge sort as we'll potentially have multiple group by keys that aren't contiguous.
} else if (groupBy.isOrderPreserving() && !(this.getTableRef().getTable().getBucketNum() != null || this.getTableRef().getTable().getIndexType() == IndexType.LOCAL)) {
