Again fix initialization of auto-tuned effective_cache_size. The previous method was overly complex and underly correct; in particular, by assigning the default value with PGC_S_OVERRIDE, it prevented later attempts to change the setting in postgresql.conf, as noted by Jeff Janes. We should just assign the default value with source PGC_S_DYNAMIC_DEFAULT, which will have the desired priority relative to the boot_val as well as user-set values.
There is still a gap in this method: if there's an explicit assignment of effective_cache_size = -1 in the postgresql.conf file, and that assignment appears before shared_buffers is assigned, the code will substitute 4 times the bootstrap default for shared_buffers, and that value will then persist (since it will have source PGC_S_FILE). I don't see any very nice way to avoid that though, and it's not a case to be expected in practice. The existing comments in guc-file.l look forward to a redesign of the DYNAMIC_DEFAULT mechanism; if that ever happens, we should consider this case as one of the things we'd like to improve. Branch ------ master Details ------- http://git.postgresql.org/pg/commitdiff/af930e606a3217db3909029c6c3f8d003ba70920 Modified Files -------------- src/backend/optimizer/path/costsize.c | 33 ++++++++++++--------------------- src/backend/utils/misc/guc-file.l | 1 + 2 files changed, 13 insertions(+), 21 deletions(-) -- Sent via pgsql-committers mailing list ([email protected]) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-committers
