Re: autovacuum hung?

From: Tom Lane
Subject: Re: autovacuum hung?
Date: ,
Msg-id: 15274.1243804436@sss.pgh.pa.us
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In response to: Re: autovacuum hung?  (Brian Cox)
List: pgsql-performance

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autovacuum hung?  (Brian Cox, )
 Re: autovacuum hung?  (Alvaro Herrera, )
 Re: autovacuum hung?  (Brian Cox, )
 Re: autovacuum hung?  (Tom Lane, )
 Re: autovacuum hung?  (Brian Cox, )
  Re: autovacuum hung?  (Tom Lane, )
 Re: autovacuum hung?  (Brian Cox, )
  Re: autovacuum hung?  (Tom Lane, )
 Re: autovacuum hung?  (Brian Cox, )
  Re: autovacuum hung?  (Tom Lane, )
  Re: autovacuum hung?  (Tom Lane, )
 Re: autovacuum hung?  (Brian Cox, )

Brian Cox <> writes:
> OK. You mentioned strace. It's got a lot of options; any in particular
> that would be useful if this happens again?

I'd just do "strace -p processID" and watch it for a little while.
If it's not hung, you'll see the process issuing kernel calls at
some rate or other.

If it is hung, you'll most likely see something like

    semop(...)

and it just sits there.  Also, if you see nothing but a series of
select()s with varying timeouts, that would suggest a stuck spinlock
(although I doubt that was happening, as it would eventually timeout
and report a failure).

            regards, tom lane


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