Horton

Support hashed aggregation with grouping sets.

Andrew Gierth <rhodiumtoad@postgresql.org>

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Commit: b5635948ab165b6070e7d05d111f966e07570d81
Author: Andrew Gierth <rhodiumtoad@postgresql.org>
Date: 2017-03-27T03:20:54Z
Releases: 10.0 
Support hashed aggregation with grouping sets.

This extends the Aggregate node with two new features: HashAggregate
can now run multiple hashtables concurrently, and a new strategy
MixedAggregate populates hashtables while doing sorted grouping.

The planner will now attempt to save as many sorts as possible when
planning grouping sets queries, while not exceeding work_mem for the
estimated combined sizes of all hashtables used.  No SQL-level changes
are required.  There should be no user-visible impact other than the
new EXPLAIN output and possible changes to result ordering when ORDER
BY was not used (which affected a few regression tests).  The
enable_hashagg option is respected.

Author: Andrew Gierth
Reviewers: Mark Dilger, Andres Freund
Discussion: https://postgr.es/m/87vatszyhj.fsf@news-spur.riddles.org.uk

Files

PathChange+/−
contrib/postgres_fdw/expected/postgres_fdw.out modified +33 −28
src/backend/commands/explain.c modified +21 −4
src/backend/executor/nodeAgg.c modified +609 −252
src/backend/lib/knapsack.c added +114 −0
src/backend/lib/Makefile modified +2 −2
src/backend/nodes/bitmapset.c modified +30 −0
src/backend/nodes/outfuncs.c modified +30 −4
src/backend/optimizer/path/costsize.c modified +6 −1
src/backend/optimizer/plan/createplan.c modified +47 −36
src/backend/optimizer/plan/planner.c modified +703 −158
src/backend/optimizer/util/pathnode.c modified +93 −57
src/include/lib/knapsack.h added +17 −0
src/include/nodes/bitmapset.h modified +6 −0
src/include/nodes/execnodes.h modified +10 −11
src/include/nodes/nodes.h modified +4 −1
src/include/nodes/plannodes.h modified +1 −1
src/include/nodes/relation.h modified +25 −5
src/include/optimizer/pathnode.h modified +2 −2
src/test/regress/expected/groupingsets.out modified +609 −7
src/test/regress/expected/tsrf.out modified +26 −24
src/test/regress/sql/groupingsets.sql modified +154 −1
src/test/regress/sql/tsrf.sql modified +2 −0

Discussion