[SPARK-17114][SQL] Fix aggregates grouped by literals with empty input #15101
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rxin
reviewed
Sep 14, 2016
| * Removes literals from group expressions in [[Aggregate]], as they have no effect to the result | ||
| * but only makes the grouping key bigger. | ||
| */ | ||
| object RemoveLiteralFromGroupExpressions extends Rule[LogicalPlan] { |
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is there an existing unit test suite for this? might be good to add a test case there too.
Contributor
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LGTM |
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Test build #65398 has finished for PR 15101 at commit
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Test build #65406 has finished for PR 15101 at commit
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cloud-fan
reviewed
Sep 15, 2016
| // Do not rewrite the aggregate if we drop all grouping expressions, because this can | ||
| // change the return semantics when the input of the Aggregate is empty. See SPARK-17114 | ||
| // for more information. | ||
| a |
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how about a.copy(groupingExpressions = Seq(grouping.head))? I think we can still remove some literal grouping if we keep one of them
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Then it might be even better to replace it with something that is trivial to hash.
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Test build #65434 has finished for PR 15101 at commit
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Contributor
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LGTM, pending jenkins. |
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Author
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retest this please |
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Test build #65435 has finished for PR 15101 at commit
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Member
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(My bad on MiMa issue -- should be fixed in master, retesting ...) |
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Test build #3270 has finished for PR 15101 at commit
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Contributor
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Merging to master/2.0. Thanks for the reviews. |
asfgit
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Sep 15, 2016
## What changes were proposed in this pull request? This PR fixes an issue with aggregates that have an empty input, and use a literals as their grouping keys. These aggregates are currently interpreted as aggregates **without** grouping keys, this triggers the ungrouped code path (which aways returns a single row). This PR fixes the `RemoveLiteralFromGroupExpressions` optimizer rule, which changes the semantics of the Aggregate by eliminating all literal grouping keys. ## How was this patch tested? Added tests to `SQLQueryTestSuite`. Author: Herman van Hovell <hvanhovell@databricks.com> Closes #15101 from hvanhovell/SPARK-17114-3. (cherry picked from commit d403562) Signed-off-by: Herman van Hovell <hvanhovell@databricks.com>
wgtmac
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Sep 19, 2016
## What changes were proposed in this pull request? This PR fixes an issue with aggregates that have an empty input, and use a literals as their grouping keys. These aggregates are currently interpreted as aggregates **without** grouping keys, this triggers the ungrouped code path (which aways returns a single row). This PR fixes the `RemoveLiteralFromGroupExpressions` optimizer rule, which changes the semantics of the Aggregate by eliminating all literal grouping keys. ## How was this patch tested? Added tests to `SQLQueryTestSuite`. Author: Herman van Hovell <hvanhovell@databricks.com> Closes apache#15101 from hvanhovell/SPARK-17114-3.
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What changes were proposed in this pull request?
This PR fixes an issue with aggregates that have an empty input, and use a literals as their grouping keys. These aggregates are currently interpreted as aggregates without grouping keys, this triggers the ungrouped code path (which aways returns a single row).
This PR fixes the
RemoveLiteralFromGroupExpressionsoptimizer rule, which changes the semantics of the Aggregate by eliminating all literal grouping keys.How was this patch tested?
Added tests to
SQLQueryTestSuite.