From c758119e5bfb47b38cf957f9a5a37ceae96fa9b3 Mon Sep 17 00:00:00 2001 From: Nathan Bossart Date: Mon, 6 Jan 2025 15:01:22 -0600 Subject: Allow changing autovacuum_max_workers without restarting. This commit introduces a new parameter named autovacuum_worker_slots that controls how many autovacuum worker slots to reserve during server startup. Modifying this new parameter's value does require a server restart, but it should typically be set to the upper bound of what you might realistically need to set autovacuum_max_workers. With that new parameter in place, autovacuum_max_workers can now be changed with a SIGHUP (e.g., pg_ctl reload). If autovacuum_max_workers is set higher than autovacuum_worker_slots, a WARNING is emitted, and the server will only start up to autovacuum_worker_slots workers at a given time. If autovacuum_max_workers is set to a value less than the number of currently-running autovacuum workers, the existing workers will continue running, but no new workers will be started until the number of running autovacuum workers drops below autovacuum_max_workers. Reviewed-by: Sami Imseih, Justin Pryzby, Robert Haas, Andres Freund, Yogesh Sharma Discussion: https://postgr.es/m/20240410212344.GA1824549%40nathanxps13 --- src/backend/utils/init/postinit.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'src/backend/utils/init/postinit.c') diff --git a/src/backend/utils/init/postinit.c b/src/backend/utils/init/postinit.c index 46dbc46a97e..01bb6a410cb 100644 --- a/src/backend/utils/init/postinit.c +++ b/src/backend/utils/init/postinit.c @@ -547,15 +547,15 @@ InitializeMaxBackends(void) Assert(MaxBackends == 0); /* Note that this does not include "auxiliary" processes */ - MaxBackends = MaxConnections + autovacuum_max_workers + + MaxBackends = MaxConnections + autovacuum_worker_slots + max_worker_processes + max_wal_senders + NUM_SPECIAL_WORKER_PROCS; if (MaxBackends > MAX_BACKENDS) ereport(ERROR, (errcode(ERRCODE_INVALID_PARAMETER_VALUE), errmsg("too many server processes configured"), - errdetail("\"max_connections\" (%d) plus \"autovacuum_max_workers\" (%d) plus \"max_worker_processes\" (%d) plus \"max_wal_senders\" (%d) must be less than %d.", - MaxConnections, autovacuum_max_workers, + errdetail("\"max_connections\" (%d) plus \"autovacuum_worker_slots\" (%d) plus \"max_worker_processes\" (%d) plus \"max_wal_senders\" (%d) must be less than %d.", + MaxConnections, autovacuum_worker_slots, max_worker_processes, max_wal_senders, MAX_BACKENDS - (NUM_SPECIAL_WORKER_PROCS - 1)))); } -- cgit v1.2.3