From 8b304b8b72b0a60f1968d39f01cf817c8df863ec Mon Sep 17 00:00:00 2001 From: Robert Haas Date: Fri, 29 Sep 2017 10:20:44 -0400 Subject: Remove replacement selection sort. At the time replacement_sort_tuples was introduced, there were still cases where replacement selection sort noticeably outperformed using quicksort even for the first run. However, those cases seem to have evaporated as a result of further improvements made since that time (and perhaps also advances in CPU technology). So remove replacement selection and the controlling GUC entirely. This makes tuplesort.c noticeably simpler and probably paves the way for further optimizations someone might want to do later. Peter Geoghegan, with review and testing by Tomas Vondra and me. Discussion: https://postgr.es/m/CAH2-WzmmNjG_K0R9nqYwMq3zjyJJK+hCbiZYNGhAy-Zyjs64GQ@mail.gmail.com --- src/backend/utils/misc/postgresql.conf.sample | 1 - 1 file changed, 1 deletion(-) (limited to 'src/backend/utils/misc/postgresql.conf.sample') diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 8ba6b1d08a5..cf4ddcd94a7 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -121,7 +121,6 @@ # you actively intend to use prepared transactions. #work_mem = 4MB # min 64kB #maintenance_work_mem = 64MB # min 1MB -#replacement_sort_tuples = 150000 # limits use of replacement selection sort #autovacuum_work_mem = -1 # min 1MB, or -1 to use maintenance_work_mem #max_stack_depth = 2MB # min 100kB #dynamic_shared_memory_type = posix # the default is the first option -- cgit v1.2.3