From: Tom Lane <tgl@sss.pgh.pa.us>
To: Josh Berkus <josh@agliodbs.com>
Cc: postgres performance list <pgsql-performance@postgresql.org>
Subject: Re: Anyone seen this kind of lock pileup?
Date: Wed, 17 Nov 2010 18:56:44 -0500
Message-ID: <27473.1290038204@sss.pgh.pa.us> (raw)
In-Reply-To: <4CE46856.7070006@agliodbs.com>
References: <4CE412F4.4090101@agliodbs.com>
<24934.1290031132@sss.pgh.pa.us>
<4CE46856.7070006@agliodbs.com>
Josh Berkus <josh@agliodbs.com> writes:
> Ok, I've collected more data. Looks like the case I was examining was
> idiosyncratic; most of these lock pile-ups involve 400 or more locks
> waiting held by around 20 different backends. Given this, taking 3
> seconds to sort that all out doesn't seem that unreasonable.
> Presumably there's a poll cycle of some sort for waiting statements?
No ... but if the lock requests were mutually exclusive, I could believe
it taking 3 seconds for all of the waiting backends to get their turn
with the lock, do whatever they were gonna do, commit, and release the
lock to the next guy.
> Anyway, the obvious answer is for the user to fix their application.
Probably.
regards, tom lane
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Cc: tgl@sss.pgh.pa.us, josh@agliodbs.com
Subject: Re: Anyone seen this kind of lock pileup?
In-Reply-To: <27473.1290038204@sss.pgh.pa.us>
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