On Sat, Jul 7, 2012 at 3:52 PM, Robert Haas <robertmh...@gmail.com> wrote:
> On Jul 7, 2012, at 9:07 AM, Euler Taveira <eu...@timbira.com> wrote:
>> On 07-07-2012 09:00, Satoshi Nagayasu wrote:
>>> I've created new patch to get/reset statistics of WAL buffer
>>> writes (flushes) caused by WAL buffer full.
>> This new statistic doesn't solve your problem (tune wal_buffers). It doesn't
>> give you the wal_buffers value. It only says "hey, I needed more buffers so I
>> write those dirty ones". It doesn't say how many. I would like to have
>> something that says "hey, you have 1000 buffers available and  you are using
>> 100 buffers (10%)". This new statistic is only useful for decreasing the
>> WALWriteLock contention.
> The number of WAL buffers that you are using is going to change so quickly as 
> to be utterly meaningless.  I don't really see that there's any statistic we 
> could gather that would tell us how many WAL buffers are needed.  This patch 
> seems like it's on the right track, at least telling you how often you're 
> running out.

We could keep a high watermark of "what's the largest percentage we've
used", perhaps?

 Magnus Hagander
 Me: http://www.hagander.net/
 Work: http://www.redpill-linpro.com/

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