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Re: Defaulting wal_sync_method to fdatasync on Linux for 9.1?

From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
To: Josh Berkus <josh(at)agliodbs(dot)com>
Cc: pgsql-performance(at)postgresql(dot)org, Greg Smith <greg(at)2ndquadrant(dot)com>
Subject: Re: Defaulting wal_sync_method to fdatasync on Linux for 9.1?
Date: 2010-11-16 23:31:34
Message-ID: 9058.1289950294@sss.pgh.pa.us (view raw or flat)
Thread:
Lists: pgsql-performance
Josh Berkus <josh(at)agliodbs(dot)com> writes:
> On 11/16/10 12:39 PM, Greg Smith wrote:
>> I want to next go through and replicate some of the actual database
>> level tests before giving a full opinion on whether this data proves
>> it's worth changing the wal_sync_method detection.  So far I'm torn
>> between whether that's the right approach, or if we should just increase
>> the default value for wal_buffers to something more reasonable.

> We'd love to, but wal_buffers uses sysV shmem.

Well, we're not going to increase the default to gigabytes, but we could
very probably increase it by a factor of 10 or so without anyone
squawking.  It's been awhile since I heard of anyone trying to run PG in
4MB shmmax.  How much would a change of that size help?

			regards, tom lane

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Next:From: Marti RaudseppDate: 2010-11-17 00:01:21
Subject: Re: Defaulting wal_sync_method to fdatasync on Linux for 9.1?
Previous:From: Josh BerkusDate: 2010-11-16 23:25:13
Subject: Re: Defaulting wal_sync_method to fdatasync on Linux for 9.1?

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