On Wed, Jan 22, 2020 at 4:06 AM Nicola Contu <nicola.co...@gmail.com> wrote: > after a few months, we started having this issue again. > So we revert the work_mem parameter to 600MB instead of 2GB. > But the issue is still there. A query went to segmentation fault, the DB went > to recovery mode and our app went to read only for a few minutes.
Hi Nicola, Hmm, a segmentation fault sounds like a different problem. Can you please share the exact error messages from PostgreSQL and OS logs? > I understand we can increase max_connections so we can have many more > segments. > > My question is : is there a way to understand the number of segments we > reached? If you're on Linux, you can probably see them with "ls /dev/shm". > Currently we have 220 max_conn so as your formula is 64 + 2* 220 we have > about 500 shared segments. > We would like to increase that number to 300 or 400 but would be great to > understand if there is a way to make sure we will solve the issue as it > requires a restart of the service. > > I know you were also talking about a redesign this part in PostgreSQL. Do you > know if anything has changed in any of the newer versions after 11.5? It's possible that we should increase a couple of constants used the formula -- I'll look into that again. But first I'd like to see if we're even investigating the right problem here.
