From: Andres Freund <andres@2ndquadrant.com>
To: Heikki Linnakangas <hlinnakangas@vmware.com>
Cc: Soni M <diptatapa@gmail.com>
Cc: pgsql-performance@postgresql.org
Subject: Re: Postgres Replaying WAL slowly
Date: Mon, 30 Jun 2014 19:14:16 +0200
Message-ID: <20140630171416.GK21422@awork2.anarazel.de> (raw)
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On 2014-06-30 19:14:24 +0300, Heikki Linnakangas wrote:
> On 06/30/2014 05:46 PM, Soni M wrote:
> >Here's what 'perf top' said on streaming replica :
> >
> >Samples: 26K of event 'cpu-clock', Event count (approx.): 19781
> > 95.97% postgres [.] 0x00000000002210f3
>
> Ok, so it's stuck doing something.. Can you get build with debug symbols
> installed, so that we could see the function name?
My guess it's a spinlock, probably xlogctl->info_lck via
RecoveryInProgress(). Unfortunately inline assembler doesn't always seem
to show up correctly in profiles...
What worked for me was to build with -fno-omit-frame-pointer - that
normally shows the callers, even if it can't generate a proper symbol
name.
Soni: Do you use Hot Standby? Are there connections active while you
have that problem? Any other processes with high cpu load?
Greetings,
Andres Freund
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Andres Freund http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Training & Services
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To: pgsql-performance@postgresql.org
Cc: andres@2ndquadrant.com, hlinnakangas@vmware.com, diptatapa@gmail.com
Subject: Re: Postgres Replaying WAL slowly
In-Reply-To: <20140630171416.GK21422@awork2.anarazel.de>
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