From 4035675111869c637883848a23b60cc1c64b473b Mon Sep 17 00:00:00 2001 From: Heikki Linnakangas Date: Mon, 2 Feb 2026 16:12:06 +0200 Subject: [PATCH 1/1] Fix pg_stat_get_backend_wait_event() for aux processes The pg_stat_activity view shows the information for aux processes, but the pg_stat_get_backend_wait_event() and pg_stat_get_backend_wait_event_type() functions did not. The straightforward fix would've been to call AuxiliaryPidGetProc(pid) if BackendPidGetProc(pid) returns NULL, like we do in pg_stat_get_activity(). It's a little inefficient though: we already have the ProcNumber of the process, so we're really only using BackendPidGetProc(pid) to check if the process is still alive. Make that check a little cheaper while we're at it. --- src/backend/utils/adt/pgstatfuncs.c | 30 +++++++++++++++++++++++------ 1 file changed, 24 insertions(+), 6 deletions(-) diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index 73ca0bb0b7f..2a573b603bd 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -817,15 +817,24 @@ pg_stat_get_backend_wait_event_type(PG_FUNCTION_ARGS) { int32 procNumber = PG_GETARG_INT32(0); PgBackendStatus *beentry; - PGPROC *proc; const char *wait_event_type = NULL; if ((beentry = pgstat_get_beentry_by_proc_number(procNumber)) == NULL) wait_event_type = ""; else if (!HAS_PGSTAT_PERMISSIONS(beentry->st_userid)) wait_event_type = ""; - else if ((proc = BackendPidGetProc(beentry->st_procpid)) != NULL) - wait_event_type = pgstat_get_wait_event_type(proc->wait_event_info); + else + { + PGPROC *proc = GetPGProcByNumber(procNumber); + uint32 raw_wait_event; + + raw_wait_event = UINT32_ACCESS_ONCE(proc->wait_event_info); + + /* check if the process is still running */ + pg_read_barrier(); + if (proc->pid == beentry->st_procpid) + wait_event_type = pgstat_get_wait_event_type(raw_wait_event); + } if (!wait_event_type) PG_RETURN_NULL(); @@ -838,15 +847,24 @@ pg_stat_get_backend_wait_event(PG_FUNCTION_ARGS) { int32 procNumber = PG_GETARG_INT32(0); PgBackendStatus *beentry; - PGPROC *proc; const char *wait_event = NULL; if ((beentry = pgstat_get_beentry_by_proc_number(procNumber)) == NULL) wait_event = ""; else if (!HAS_PGSTAT_PERMISSIONS(beentry->st_userid)) wait_event = ""; - else if ((proc = BackendPidGetProc(beentry->st_procpid)) != NULL) - wait_event = pgstat_get_wait_event(proc->wait_event_info); + else + { + PGPROC *proc = GetPGProcByNumber(procNumber); + uint32 raw_wait_event; + + raw_wait_event = UINT32_ACCESS_ONCE(proc->wait_event_info); + + /* check if the process is still running */ + pg_read_barrier(); + if (proc->pid == beentry->st_procpid) + wait_event = pgstat_get_wait_event(raw_wait_event); + } if (!wait_event) PG_RETURN_NULL(); -- 2.47.3