From: Andres Freund <andres@anarazel.de>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: pgsql-performance@postgresql.org, Josh Berkus <josh@agliodbs.com>
Cc: Greg Smith <greg@2ndquadrant.com>
Subject: Re: Defaulting wal_sync_method to fdatasync on Linux for 9.1?
Date: Wed, 17 Nov 2010 02:01:24 +0100
Message-ID: <201011170201.24782.andres@anarazel.de> (raw)
In-Reply-To: <10822.1289955088@sss.pgh.pa.us>
References: <AANLkTi=n3zxiLNFhbpiN=JPQPwB=BhXf9iepw1KOEs8U@mail.gmail.com>
<201011170130.10720.andres@anarazel.de>
<10822.1289955088@sss.pgh.pa.us>
On Wednesday 17 November 2010 01:51:28 Tom Lane wrote:
> Andres Freund <andres@anarazel.de> writes:
> > On Wednesday 17 November 2010 00:31:34 Tom Lane wrote:
> >> Well, we're not going to increase the default to gigabytes
> >
> > Especially not as I don't think it will have any effect after
> > wal_segment_size as that will force a write-out anyway. Or am I
> > misremembering the implementation?
>
> Well, there's a forced fsync after writing the last page of an xlog
> file, but I don't believe that proves that more than 16MB of xlog
> buffers is useless. Other processes could still be busy filling the
> buffers.
Maybe I am missing something, but I think the relevant AdvanceXLInsertBuffer()
is currently called with WALInsertLock held?
Andres
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To: pgsql-performance@postgresql.org
Cc: andres@anarazel.de, tgl@sss.pgh.pa.us, josh@agliodbs.com, greg@2ndquadrant.com
Subject: Re: Defaulting wal_sync_method to fdatasync on Linux for 9.1?
In-Reply-To: <201011170201.24782.andres@anarazel.de>
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