Re: checkpointer code behaving strangely on postmaster -T

Alvaro Herrera <alvherre@commandprompt.com> writes:
> Excerpts from Tom Lane's message of jue may 10 02:27:32 -0400 2012:
>> Alvaro Herrera <alvherre@alvh.no-ip.org> writes:
> I noticed while doing some tests that the checkpointer process does not
> recover very nicely after a backend crashes under postmaster -T

> It seems to me that the bug is in the postmaster state machine rather
> than checkpointer itself.  After a few false starts, this seems to fix
> it:

> --- a/src/backend/postmaster/postmaster.c
> +++ b/src/backend/postmaster/postmaster.c
> @@ -2136,6 +2136,8 @@ pmdie(SIGNAL_ARGS)
>                     signal_child(WalWriterPID, SIGTERM);
>                 if (BgWriterPID != 0)
>                     signal_child(BgWriterPID, SIGTERM);
> +               if (FatalError && CheckpointerPID != 0)
> +                   signal_child(CheckpointerPID, SIGUSR2);

Surely we do not want the checkpointer doing a shutdown checkpoint here.
If we need it to die immediately, SIGQUIT is the way.  If we want a
shutdown checkpoint, that has to wait till after everything else is
known dead.  So while I agree this may be a state machine bug, that
doesn't look like a good fix.
        regards, tom lane