Re: SIGUSR1 pingpong between master na autovacum launcher causes crash

Alvaro Herrera <alvherre@commandprompt.com> writes:
> Zdenek Kotala wrote:
>> Just a confirmation that Alvaro's patch+ReleasePostmasterChildSlot() fix
>> solves the problem and PostgreSQL survives well during a memory
>> shortages.

> So this patch would do it.

Looks good to me, but I think you should also increase the avlauncher
delay from 100ms -> 1s as Zdenek suggested.

> I think this stuff about postmaster child slots is later than
> launcher/worker split.  I don't recall seeing it before.

Yeah, I added that recently to try to detect postmaster children
that exit without cleaning up properly.  I seem to have missed this
error case :-(.  Actually it looks like fork failure for regular
backends gets it wrong too :-( :-( --- would you please also add one
in the pid<0 path in BackendStartup?  I think this logic is in 8.4
too, in which case it'll need to be back-patched.
        regards, tom lane