[GitHub] [hive] vineetgarg02 commented on a change in pull request #1439: HIVE-24084 cost aggr

[GitBox <gi...@apache.org>]

vineetgarg02 commented on a change in pull request #1439:
URL: https://github.com/apache/hive/pull/1439#discussion_r479508618



##########
File path: ql/src/java/org/apache/hadoop/hive/ql/optimizer/calcite/cost/HiveOnTezCostModel.java
##########
@@ -89,22 +89,23 @@ public RelOptCost getAggregateCost(HiveAggregate aggregate) {
     } else {
       final RelMetadataQuery mq = aggregate.getCluster().getMetadataQuery();
       // 1. Sum of input cardinalities
-      final Double rCount = mq.getRowCount(aggregate.getInput());
-      if (rCount == null) {
+      final Double inputRowCount = mq.getRowCount(aggregate.getInput());
+      final Double rowCount = mq.getRowCount(aggregate);

Review comment:
       Can we change `rowCount` to `outputRowCount`? This will make the change more readable.

##########
File path: ql/src/java/org/apache/hadoop/hive/ql/optimizer/calcite/cost/HiveOnTezCostModel.java
##########
@@ -89,22 +89,23 @@ public RelOptCost getAggregateCost(HiveAggregate aggregate) {
     } else {
       final RelMetadataQuery mq = aggregate.getCluster().getMetadataQuery();
       // 1. Sum of input cardinalities
-      final Double rCount = mq.getRowCount(aggregate.getInput());
-      if (rCount == null) {
+      final Double inputRowCount = mq.getRowCount(aggregate.getInput());
+      final Double rowCount = mq.getRowCount(aggregate);
+      if (inputRowCount == null || rowCount == null) {
         return null;
       }
       // 2. CPU cost = sorting cost
-      final double cpuCost = algoUtils.computeSortCPUCost(rCount);
+      final double cpuCost = algoUtils.computeSortCPUCost(rowCount) + inputRowCount * algoUtils.getCpuUnitCost();
       // 3. IO cost = cost of writing intermediary results to local FS +
       //              cost of reading from local FS for transferring to GBy +
       //              cost of transferring map outputs to GBy operator
       final Double rAverageSize = mq.getAverageRowSize(aggregate.getInput());
       if (rAverageSize == null) {
         return null;
       }
-      final double ioCost = algoUtils.computeSortIOCost(new Pair<Double,Double>(rCount,rAverageSize));
+      final double ioCost = algoUtils.computeSortIOCost(new Pair<Double, Double>(rowCount, rAverageSize));

Review comment:
       `rAverageSize` is based on input row count but `rowCount` is output row count. Is this intended or should average row size be computed based on output row count?

##########
File path: ql/src/java/org/apache/hadoop/hive/ql/optimizer/calcite/rules/HiveAggregateJoinTransposeRule.java
##########
@@ -303,6 +305,90 @@ public void onMatch(RelOptRuleCall call) {
     }
   }
 
+  /**
+   * Determines weather the give grouping is unique.
+   *
+   * Consider a join which might produce non-unique rows; but later the results are aggregated again.
+   * This method determines if there are sufficient columns in the grouping which have been present previously as unique column(s).
+   */
+  private boolean isGroupingUnique(RelNode input, ImmutableBitSet groups) {
+    if (groups.isEmpty()) {
+      return false;
+    }
+    RelMetadataQuery mq = input.getCluster().getMetadataQuery();
+    Set<ImmutableBitSet> uKeys = mq.getUniqueKeys(input);

Review comment:
       If the purpose of this method is to determine that given a set of columns are unique or not you can use `areColumnsUnique` as @jcamachor  suggested.




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