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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