On Mon, Jan 30, 2023 at 2:51 PM Justin Pryzby <pry...@telsasoft.com> wrote:
> On Mon, Jan 30, 2023 at 05:47:49PM +0000, Mok wrote: > > Hi, > > > > We've started to observe instances of one of our databases stalling for a > > few seconds. > > > > We see a spike in wal write locks then nothing for a few seconds. After > > which we have spike latency as processes waiting to get to the db can do > > so. > > > > There is nothing in the postgres logs that give us any clues to what > could > > be happening, no locks, unusually high/long running transactions, just a > > pause and resume. > > > > Could anyone give me any advice as to what to look for when it comes to > > checking the underlying disk that the db is on? > > What version postgres? What settings have non-default values ? > > > What OS/version? What environment/hardware? VM/image/provider/... > > > > Have you enabled logging for vacuum/checkpoints/locks ? > > https://wiki.postgresql.org/wiki/Slow_Query_Questions > > > In addition to previous questions, if possible, a SELECT * FROM pg_stat_activity at the moment of the stall. The most important information is the wait_event column. My guess is the disk, but just the select at the right moment can answer this. -- José Arthur Benetasso Villanova
