diff options
Diffstat (limited to 'src/backend')
| -rw-r--r-- | src/backend/storage/lmgr/proc.c | 24 | ||||
| -rw-r--r-- | src/backend/utils/activity/wait_event.c | 41 |
2 files changed, 57 insertions, 8 deletions
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 897045ee272..692f21ef6a8 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -448,6 +448,9 @@ InitProcess(void) OwnLatch(&MyProc->procLatch); SwitchToSharedLatch(); + /* now that we have a proc, report wait events to shared memory */ + pgstat_set_wait_event_storage(&MyProc->wait_event_info); + /* * We might be reusing a semaphore that belonged to a failed process. So * be careful and reinitialize its value here. (This is not strictly @@ -601,6 +604,9 @@ InitAuxiliaryProcess(void) OwnLatch(&MyProc->procLatch); SwitchToSharedLatch(); + /* now that we have a proc, report wait events to shared memory */ + pgstat_set_wait_event_storage(&MyProc->wait_event_info); + /* Check that group locking fields are in a proper initial state. */ Assert(MyProc->lockGroupLeader == NULL); Assert(dlist_is_empty(&MyProc->lockGroupMembers)); @@ -884,10 +890,15 @@ ProcKill(int code, Datum arg) /* * Reset MyLatch to the process local one. This is so that signal * handlers et al can continue using the latch after the shared latch - * isn't ours anymore. After that clear MyProc and disown the shared - * latch. + * isn't ours anymore. + * + * Similarly, stop reporting wait events to MyProc->wait_event_info. + * + * After that clear MyProc and disown the shared latch. */ SwitchBackToLocalLatch(); + pgstat_reset_wait_event_storage(); + proc = MyProc; MyProc = NULL; DisownLatch(&proc->procLatch); @@ -952,13 +963,10 @@ AuxiliaryProcKill(int code, Datum arg) /* Cancel any pending condition variable sleep, too */ ConditionVariableCancelSleep(); - /* - * Reset MyLatch to the process local one. This is so that signal - * handlers et al can continue using the latch after the shared latch - * isn't ours anymore. After that clear MyProc and disown the shared - * latch. - */ + /* look at the equivalent ProcKill() code for comments */ SwitchBackToLocalLatch(); + pgstat_reset_wait_event_storage(); + proc = MyProc; MyProc = NULL; DisownLatch(&proc->procLatch); diff --git a/src/backend/utils/activity/wait_event.c b/src/backend/utils/activity/wait_event.c index 840ebef92ab..accc1eb5776 100644 --- a/src/backend/utils/activity/wait_event.c +++ b/src/backend/utils/activity/wait_event.c @@ -7,6 +7,17 @@ * * IDENTIFICATION * src/backend/postmaster/wait_event.c + * + * NOTES + * + * To make pgstat_report_wait_start() and pgstat_report_wait_end() as + * lightweight as possible, they do not check if shared memory (MyProc + * specifically, where the wait event is stored) is already available. Instead + * we initially set my_wait_event_info to a process local variable, which then + * is redirected to shared memory using pgstat_set_wait_event_storage(). For + * the same reason pgstat_track_activities is not checked - the check adds + * more work than it saves. + * * ---------- */ #include "postgres.h" @@ -23,6 +34,36 @@ static const char *pgstat_get_wait_timeout(WaitEventTimeout w); static const char *pgstat_get_wait_io(WaitEventIO w); +static uint32 local_my_wait_event_info; +uint32 *my_wait_event_info = &local_my_wait_event_info; + + +/* + * Configure wait event reporting to report wait events to *wait_event_info. + * *wait_event_info needs to be valid until pgstat_reset_wait_event_storage() + * is called. + * + * Expected to be called during backend startup, to point my_wait_event_info + * into shared memory. + */ +void +pgstat_set_wait_event_storage(uint32 *wait_event_info) +{ + my_wait_event_info = wait_event_info; +} + +/* + * Reset wait event storage location. + * + * Expected to be called during backend shutdown, before the location set up + * pgstat_set_wait_event_storage() becomes invalid. + */ +void +pgstat_reset_wait_event_storage(void) +{ + my_wait_event_info = &local_my_wait_event_info; +} + /* ---------- * pgstat_get_wait_event_type() - * |