Major upgrade would be very painful because there are many application running on different servers but same database server. Their tests would take too much time. So I will try to go with minor upgrade.
Thanks for your help, have a good day. >> > Remaining suggestions/questions: > > 1) If it still exists look in Postgres log around 2018-05-30 02:00:00, > the time the problematic queries started, to see if there are any entries > of note. > > 2) You are on Postgres 9.5.3 and the most recent release 9.5.13. There > have been a lot of bug fixes in the interim and it would be a good idea to > upgrade. It is minor release upgrade but I would go through the release > notes first: > > https://www.postgresql.org/docs/9.5/static/release.html > > as there some thing that might require your action. > > 3) I suggest 2) because a quick scan of the release notes found this: > > https://www.postgresql.org/docs/9.5/static/release-9-5-11.html > > " > > Cope with failure to start a parallel worker process (Amit Kapila, Robert > Haas) > > Parallel query previously tended to hang indefinitely if a worker could > not be started, as the result of fork() failure or other low-probability > problems. > " > > Is it possible that parallel query: > > https://www.postgresql.org/docs/10/static/when-can-parallel- > query-be-used.html > > is in use? > > > >> >> >> >> >> -- Adrian Klaver >> adrian.kla...@aklaver.com <mailto:adrian.kla...@aklaver.com> >> >> >> >> > > -- > Adrian Klaver > adrian.kla...@aklaver.com >
