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List:       postgresql-admin
Subject:    Re: [ADMIN] Shared memory corrupted?
From:       Tom Lane <tgl () sss ! pgh ! pa ! us>
Date:       2003-10-30 22:14:19
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Jeff Boes <jboes@nexcerpt.com> writes:
> [How would a plperl function that changes the local behavior of SIGALRM 
> affect the backend?]

IIRC, SIGALRM is used for two things: one, to trigger a deadlock check
cycle if we wait too long for a lock (see deadlock_timeout), and two,
to implement statement_timeout.  If you are using statement_timeout then
I think it would be dangerous to mess with SIGALRM at all.  If you are
not, then I think it would be all right to modify the SIGALRM handler
setting locally, as long as you restore it to its original setting when
you are done.  Don't try to run any database access operations while you
have a nonstandard setting of the SIGALRM handler, though, or you risk
problems with deadlock checking.

			regards, tom lane

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