Re: Assertion failure when the non-exclusive pg_stop_backup aborted.

On Fri, Sep 22, 2017 at 10:41 AM, Craig Ringer <craig@2ndquadrant.com> wrote:
> Another one to watch out for is that elog(...) and ereport(...) invoke
> CHECK_FOR_INTERRUPTS. That's given me exciting surprises before when
> combined with assertion checking and various exit cleanup hooks.

Ahah. Good point. In this case LWLockWaitForVar() is one thing to
worry about if LWLock tracing is enabled because it can log things
before holding the existing interrupts. This can be avoided easily in
the case of this issue by updating sessionBackupState before calling
WALInsertLockRelease and while holding the WAL insert lock. Surely
this meritates a comment in the patch we want here.
-- 
Michael