Re: hung backends stuck in spinlock heavy endless loop

From: Andres Freund <andres(at)2ndquadrant(dot)com>
To: Peter Geoghegan <pg(at)heroku(dot)com>
Cc: Merlin Moncure <mmoncure(at)gmail(dot)com>, PostgreSQL-development <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: hung backends stuck in spinlock heavy endless loop
Date: 2015-01-13 23:21:31
Message-ID: 20150113232131.GC5245@awork2.anarazel.de
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On 2015-01-13 15:17:15 -0800, Peter Geoghegan wrote:
> I'm inclined to think that this is a livelock, and so the problem
> isn't evident from the structure of the B-Tree, but it can't hurt to
> check.

My guess is rather that it's contention on the freelist lock via
StrategyGetBuffer's. I've seen profiles like this due to exactly that
before - and it fits to parallel loading quite well.

Greetings,

Andres Freund

--
Andres Freund http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Training & Services

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