Re: Choosing a filesystem - Mailing list pgsql-performance

From Bruce Momjian
Subject Re: Choosing a filesystem
Date
Msg-id 200809231702.m8NH21118074@momjian.us
Whole thread Raw
In response to Re: Choosing a filesystem  ("Merlin Moncure" <mmoncure@gmail.com>)
Responses Re: Choosing a filesystem  (Simon Riggs <simon@2ndQuadrant.com>)
List pgsql-performance
Merlin Moncure wrote:
> > although for postgres the thing that you are doing the fsync on is the WAL
> > log file. that is a single (usually) contiguous file. As such it is very
> > efficiant to write large chunks of it. so while you will degrade from the
> > battery-only mode, the fact that the controller can flush many requests
> > worth of writes out to the WAL log at once while you fill the cache with
> > them one at a time is still a significant win.
>
> The heap files have to be synced as well during checkpoints, etc.

True, but as of 8.3 those checkpoint fsyncs are spread over the interval
between checkpoints.

--
  Bruce Momjian  <bruce@momjian.us>        http://momjian.us
  EnterpriseDB                             http://enterprisedb.com

  + If your life is a hard drive, Christ can be your backup. +

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