Use more efficient hashtable for execGrouping.c to speed up hash aggregation.
The more efficient hashtable speeds up hash-aggregations with more than a few hundred groups significantly. Improvements of over 120% have been measured. Due to the the different hash table queries that not fully determined (e.g. GROUP BY without ORDER BY) may change their result order. The conversion is largely straight-forward, except that, due to the static element types of simplehash.h type hashes, the additional data some users store in elements (e.g. the per-group working data for hash aggregaters) is now stored in TupleHashEntryData->additional. The meaning of BuildTupleHashTable's entrysize (renamed to additionalsize) has been changed to only be about the additionally stored size. That size is only used for the initial sizing of the hash-table. Reviewed-By: Tomas Vondra Discussion: <20160727004333.r3e2k2y6fvk2n...@alap3.anarazel.de> Branch ------ master Details ------- http://git.postgresql.org/pg/commitdiff/5dfc198146b49ce7ecc8a1fc9d5e171fb75f6ba5 Modified Files -------------- src/backend/executor/execGrouping.c | 155 ++++++++++++------------------ src/backend/executor/nodeAgg.c | 64 ++++++------ src/backend/executor/nodeRecursiveunion.c | 17 +--- src/backend/executor/nodeSetOp.c | 46 ++++----- src/backend/executor/nodeSubplan.c | 6 +- src/backend/optimizer/plan/planner.c | 6 ++ src/include/executor/executor.h | 2 +- src/include/nodes/execnodes.h | 32 +++--- src/tools/pgindent/typedefs.list | 2 + 9 files changed, 144 insertions(+), 186 deletions(-) -- Sent via pgsql-committers mailing list (pgsql-committers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-committers
