Spiros Ioannou <sivann@inaccess.com> writes:
> We upgraded to 9.4.4 from 8.4 We have tried 9.3.x in the past with success.
> Unfortunately in 9.4 gets stuck 2-3 times a week.
> Lots of queries seem stuck, that is they have waiting:false. Queries can be
> COMMIT or INSERT.
> No blocking locks seem to exist.
> strace reveals that all stuck processes they are in semop
> semop(2064417, {{0, -1, 0}}, 1^C <unfinished ...>
Stack traces of the stuck processes might help determine what's going on.
https://wiki.postgresql.org/wiki/Generating_a_stack_trace_of_a_PostgreSQL_backend
Please try to capture traces for both the COMMIT and INSERT cases,
as they're almost certainly different.
regards, tom lane