Re: [Bizgres-general] WAL bypass for INSERT, UPDATE and

Simon Riggs <simon@2ndquadrant.com>

From: Simon Riggs <simon@2ndquadrant.com>

To: Rick Gigger <rick@alpinenetworking.com>

Cc: Christopher Kings-Lynne <chriskl@familyhealth.com.au>, Bruce Momjian <pgman@candle.pha.pa.us>, Tom Lane <tgl@sss.pgh.pa.us>, Martijn van Oosterhout <kleptog@svana.org>, Greg Stark <gsstark@mit.edu>, Rod Taylor <pg@rbt.ca>, Qingqing Zhou <zhouqq@cs.toronto.edu>, pgsql-hackers@postgresql.org

Date: 2006-02-07T09:40:37Z

Lists: pgsql-hackers

On Mon, 2006-02-06 at 21:07 -0700, Rick Gigger wrote:
> I was thinking the exact same thing.  Except  the "and just fsync()  
> dirty pages on commit" part.  Wouldn't that actually make the  
> situation worse?  I thought the whole point of WAL was that it was  
> more efficient to fsync all of the changes in one sequential write in  
> one file rather than fsyncing all of the separate dirty pages.

This would apply to only a single relation, so would be just as
efficient a write to the database as to WAL. The proposed route is to
sync to the database, but not to WAL, thus halving the required I/O.

Yes, its designed for large data loads.

Best Regards, Simon Riggs