On Thu, Jun 26, 2025 at 2:48 AM James Pang wrote:
>we faced this issue 3 times this week, each time last only 2 seconds, so
> not easy to run perf in peak business time to capture that, anyway, I will
> try. before that, I want to understand if "os page cache" or "pg buffer
> cache" can con
thanks for you explaination, from Postgresql perspective, is it possible
to see bgwriter,or checkpointer blocking backend process reading/wrting ?
or vice versa ?
Thanks,
James
Frits Hoogland 於 2025年6月26日週四 下午4:07寫道：
> Postgres lives as a process in linux, and keeps its own cache, and tries
Postgres lives as a process in linux, and keeps its own cache, and tries to use
that as much as possible for data. This is postgres shared buffers, commonly
called the buffer cache.
For WAL, sessions write to the wal buffer (separate from the postgres buffer
cache), and need to write to disk u
in addition to "DataFileRead", actually we have more session waiting on
"extend", and we enabled log_lock, for example
2025-06-24 18:00:11.368 :[1865315]:[4-1]:mbsLOG: process 1865315 still
waiting for ExclusiveLock on extension of relation 14658239 of database
16384 after 1000.161 ms
2025-06-
