Ensure to pushdown the aggregation for count(const)

Aggregate pushdown should be enabled even with count(const) query. Since SimplifyCountOverConstant is applied after PushAggregationIntoTableScan, the aggregation pushdown does not treat count(*) and count(const) uniformally.
trinodb · Jul 23, 2020 · 84d3b06 · 84d3b06
1 parent 8db1d3a
commit 84d3b06
Show file tree

Hide file tree

Showing 2 changed files with 4 additions and 6 deletions.
diff --git a/presto-main/src/main/java/io/prestosql/sql/planner/PlanOptimizers.java b/presto-main/src/main/java/io/prestosql/sql/planner/PlanOptimizers.java
@@ -427,7 +427,8 @@ public PlanOptimizers(
                                         new MergeLimitWithDistinct(),
                                         new PruneCountAggregationOverScalar(metadata),
                                         new PruneOrderByInAggregation(metadata),
-                                        new RewriteSpatialPartitioningAggregation(metadata)))
+                                        new RewriteSpatialPartitioningAggregation(metadata),
+                                        new SimplifyCountOverConstant(metadata)))
                                 .build()),
                 new IterativeOptimizer(
                         ruleStats,
@@ -552,11 +553,6 @@ public PlanOptimizers(
                 new UnaliasSymbolReferences(metadata), // Run again because predicate pushdown and projection pushdown might add more projections
                 columnPruningOptimizer, // Make sure to run this before index join. Filtered projections may not have all the columns.
                 new IndexJoinOptimizer(metadata), // Run this after projections and filters have been fully simplified and pushed down
-                new IterativeOptimizer(
-                        ruleStats,
-                        statsCalculator,
-                        estimatedExchangesCostCalculator,
-                        ImmutableSet.of(new SimplifyCountOverConstant(metadata))),
                 new LimitPushDown(), // Run LimitPushDown before WindowFilterPushDown
                 new WindowFilterPushDown(metadata), // This must run after PredicatePushDown and LimitPushDown so that it squashes any successive filter nodes and limits
                 new IterativeOptimizer(

diff --git a/...esql/src/test/java/io/prestosql/plugin/postgresql/TestPostgreSqlIntegrationSmokeTest.java b/...esql/src/test/java/io/prestosql/plugin/postgresql/TestPostgreSqlIntegrationSmokeTest.java
@@ -297,6 +297,8 @@ public void testAggregationPushdown()
 
         assertAggregationPushedDown("SELECT count(*) FROM nation");
         assertAggregationPushedDown("SELECT count(nationkey) FROM nation");
+        assertAggregationPushedDown("SELECT count(1) FROM nation");
+        assertAggregationPushedDown("SELECT count() FROM nation");
         assertAggregationPushedDown("SELECT regionkey, min(nationkey) FROM nation GROUP BY regionkey");
         assertAggregationPushedDown("SELECT regionkey, max(nationkey) FROM nation GROUP BY regionkey");
         assertAggregationPushedDown("SELECT regionkey, sum(nationkey) FROM nation GROUP BY regionkey");