On Wed, Oct 5, 2011 at 10:30 PM, Magnus Hagander <mag...@hagander.net> wrote: > When walsender calls out to do_pg_stop_backup() (during base backups), > it is not possible to terminate the process with a SIGTERM - it > requires a SIGKILL. This can leave unkillable backends for example if > archive_mode is on and archive_command is failing (or not set). A > similar thing would happen in other cases if walsender calls out to > something that would block (do_pg_start_backup() for example), but the > stop one is easy to provoke.
Good catch! > ISTM one way to fix it is the attached, which is to have walsender set > the "global" flags saying that we have received sigterm, which in turn > causes the CHECK_FOR_INTERRUPTS() calls in the routines to properly > exit the process. AFAICT it works fine. Any holes in this approach? Very simple patch. Looks fine. > Second, I wonder if we should add a SIGINT handler as well, that would > make it possible to send a cancel signal. Given that the end result > would be the same (at least if we want to keep with the "walsender is > simple" path), I'm not sure it's necessary - but it would at least > help those doing pg_cancel_backend()... thoughts? I don't think that's necessary because, as you suggested, there is no use case for *now*. We can add that handler when someone proposes the feature which requires that. Regards, -- Fujii Masao NIPPON TELEGRAPH AND TELEPHONE CORPORATION NTT Open Source Software Center -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
