Re: [ADMIN] Vacuum error on database postgres - Mailing list pgsql-hackers

From Jeff Davis
Subject Re: [ADMIN] Vacuum error on database postgres
Date
Msg-id 1158271045.29889.143.camel@dogma.v10.wvs
Whole thread Raw
In response to Re: [ADMIN] Vacuum error on database postgres  (Tom Lane <tgl@sss.pgh.pa.us>)
Responses Re: [ADMIN] Vacuum error on database postgres  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-hackers
On Thu, 2006-09-14 at 11:20 -0400, Tom Lane wrote:
> andy <andy@squeakycode.net> writes:
> > Tom Lane wrote:
> >> andy <andy@squeakycode.net> writes:
> This behavior dates from a time when there was no good alternative.
> One possible fix today would be to make ANALYZE take
> ShareUpdateExclusive lock instead, thus ensuring there is only one
> ANALYZE at a time on a table.  However I'm a bit concerned by the
> possibility that ANALYZE-inside-a-transaction could accumulate a
> whole bunch of such locks in a random order, leading at least to
> a risk of deadlocks against other ANALYZEs.  (We have to hold the
> lock till commit, else we aren't fixing the problem.)  Do we need a
> specialized lock type just for ANALYZE?  Would sorting the target
> list of rel OIDs be enough?  Perhaps it's not worth worrying about?
> 

How would creating a new lock type avoid deadlocks when an ANALYZE is
accumulating the locks in random order?

Regards,Jeff Davis





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