Hi James, Take a look here, in the links you will find many info and real examples for LockManager issues.
https://ardentperf.com/2024/03/03/postgres-indexes-partitioning-and-lwlocklockmanager-scalability/ Luiz On Tue, Apr 9, 2024 at 4:08 AM James Pang <jamespang...@gmail.com> wrote: > 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 >
