Обсуждение: SIGALRM in autovacuum.c

Is this correct in autovacuum.c?
    pqsignal(SIGALRM, handle_sig_alarm);

Should it be SIG_IGN?  I don't see autovacuum using a timer or a reason
it is calling the backend's timer routine.

--  Bruce Momjian                        |  http://candle.pha.pa.us pgman@candle.pha.pa.us               |  (610)
359-1001+  If your life is a hard drive,     |  13 Roberts Road +  Christ can be your backup.        |  Newtown Square,
Pennsylvania19073
 

Bruce Momjian wrote:
> Is this correct in autovacuum.c?
> 
>         pqsignal(SIGALRM, handle_sig_alarm);
> 
> Should it be SIG_IGN?  I don't see autovacuum using a timer or a reason
> it is calling the backend's timer routine.

FYI, the comment above this says:
    * Set up signal handlers.  We operate on databases much like a regular    * backend, so we use the same signal
handling. See equivalent code in    * tcop/postgres.c.
 

but can you have autovacuum running as a regular backend?  I didn't
think so.

--  Bruce Momjian                        |  http://candle.pha.pa.us pgman@candle.pha.pa.us               |  (610)
359-1001+  If your life is a hard drive,     |  13 Roberts Road +  Christ can be your backup.        |  Newtown Square,
Pennsylvania19073
 

Bruce Momjian <pgman@candle.pha.pa.us> writes:
> Is this correct in autovacuum.c?
>         pqsignal(SIGALRM, handle_sig_alarm);
> Should it be SIG_IGN?

Absolutely not.  autovacuum takes locks just like a backend and has to
be able to handle deadlock timeout checks.
        regards, tom lane