Perform one only projection to compute agg arguments. Previously we did a ExecProject() for each individual aggregate argument. That turned out to be a performance bottleneck in queries with multiple aggregates.
Doing all the argument computations in one ExecProject() is quite a bit cheaper because ExecProject's fastpath can do the work at once in a relatively tight loop, and because it can get all the required columns with a single slot_getsomeattr and save some other redundant setup costs. Author: Andres Freund Reviewed-By: Heikki Linnakangas Discussion: https://postgr.es/m/[email protected] Branch ------ master Details ------- http://git.postgresql.org/pg/commitdiff/8ed3f11bb045ad7a3607690be668dbd5b3cc31d7 Modified Files -------------- src/backend/executor/nodeAgg.c | 167 ++++++++++++++++++++++++++++------------- src/include/nodes/execnodes.h | 4 + 2 files changed, 119 insertions(+), 52 deletions(-) -- Sent via pgsql-committers mailing list ([email protected]) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-committers
