kgyrtkirk commented on a change in pull request #1439:
URL: https://github.com/apache/hive/pull/1439#discussion_r485001912
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File path:
ql/src/java/org/apache/hadoop/hive/ql/optimizer/calcite/rules/HiveAggregateJoinTransposeRule.java
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@@ -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:
yes; I've explored using `areColumnsUnique` because it matches the
usecase here - however for some tests it emitted some NPEs so I've gone back to
the `getUniqueKeys` approach
I'll file a jira for `areColumnsUnique` when I know what's wrong with it..
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