| From: | James Pang <jamespang886(at)gmail(dot)com> |
|---|---|
| To: | pgsql-performance(at)lists(dot)postgresql(dot)org |
| Subject: | LWlock:LockManager waits |
| Date: | 2024-04-09 03:07:49 |
| Message-ID: | CAHgTRff6-WVufuuO9L2WhAagHKqWprQx9y6hQB+sjxiedKhz5w@mail.gmail.com |
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| Lists: | pgsql-performance |
we found sometimes , with many sessions running same query "select ..."
at the same time, saw many sessions waiting on "LockManager". for example,
pg_stat_activity show. It's a production server, so no enable
trace_lwlocks flag. could you direct me what's the possible reason and how
to reduce this "lockmanager" lock? all the sql statement are "select " ,no
DML.
time wait_event
count(pid)
2024-04-08 09:00:06.043996+00 | DataFileRead | 42
2024-04-08 09:00:06.043996+00 | | 15
2024-04-08 09:00:06.043996+00 | LockManager | 31
2024-04-08 09:00:06.043996+00 | BufferMapping | 46
2024-04-08 09:00:07.114015+00 | LockManager | 43
2024-04-08 09:00:07.114015+00 | DataFileRead | 28
2024-04-08 09:00:07.114015+00 | ClientRead | 11
2024-04-08 09:00:07.114015+00 | | 11
Thanks,
James
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