Raghavendra Rao J S V <raghavendrajsv(at)gmail(dot)com> writes:
> Receiving below error while taking the backup using pg_dump. Please help me
> why and how to resolve this.
> pg_dump: [archiver (db)] query failed: FATAL: semop(id=10649641) failed:
> Identifier removed
Are you running on a platform that uses systemd? If so, see
https://www.postgresql.org/docs/current/static/kernel-resources.html#SYSTEMD-REMOVEIPC
If it's not systemd, I'd still say that something kneecapped your PG
server by removing its semaphores. Restarting the postmaster will
clear the problem transiently, but do nothing to prevent a recurrence.
regards, tom lane