diff options
Diffstat (limited to 'src/backend/utils/init/postinit.c')
| -rw-r--r-- | src/backend/utils/init/postinit.c | 34 |
1 files changed, 34 insertions, 0 deletions
diff --git a/src/backend/utils/init/postinit.c b/src/backend/utils/init/postinit.c index 3b50ce19a2c..a024b1151d0 100644 --- a/src/backend/utils/init/postinit.c +++ b/src/backend/utils/init/postinit.c @@ -558,6 +558,40 @@ InitializeMaxBackends(void) } /* + * Initialize the number of fast-path lock slots in PGPROC. + * + * This must be called after modules have had the chance to alter GUCs in + * shared_preload_libraries and before shared memory size is determined. + * + * The default max_locks_per_xact=64 means 4 groups by default. + * + * We allow anything between 1 and 1024 groups, with the usual power-of-2 + * logic. The 1 is the "old" size with only 16 slots, 1024 is an arbitrary + * limit (matching max_locks_per_xact = 16k). Values over 1024 are unlikely + * to be beneficial - there are bottlenecks we'll hit way before that. + */ +void +InitializeFastPathLocks(void) +{ + /* Should be initialized only once. */ + Assert(FastPathLockGroupsPerBackend == 0); + + /* we need at least one group */ + FastPathLockGroupsPerBackend = 1; + + while (FastPathLockGroupsPerBackend < FP_LOCK_GROUPS_PER_BACKEND_MAX) + { + /* stop once we exceed max_locks_per_xact */ + if (FastPathLockGroupsPerBackend * FP_LOCK_SLOTS_PER_GROUP >= max_locks_per_xact) + break; + + FastPathLockGroupsPerBackend *= 2; + } + + Assert(FastPathLockGroupsPerBackend <= FP_LOCK_GROUPS_PER_BACKEND_MAX); +} + +/* * Early initialization of a backend (either standalone or under postmaster). * This happens even before InitPostgres. * |