Re: Improvement of checkpoint IO scheduler for stable transaction responses - Mailing list pgsql-hackers

From Stephen Frost
Subject Re: Improvement of checkpoint IO scheduler for stable transaction responses
Date
Msg-id 20130718194024.GR15510@tamriel.snowman.net
Whole thread Raw
In response to Re: Improvement of checkpoint IO scheduler for stable transaction responses  (Greg Smith <greg@2ndQuadrant.com>)
List pgsql-hackers
* Greg Smith (greg@2ndQuadrant.com) wrote:
> The first word that comes to mind for for just disregarding the end
> time is that it's a sloppy checkpoint.  There is all sorts of sloppy
> behavior you might do here, but I've worked under the assumption
> that ignoring the contract with the administrator was frowned on by
> this project.  If people want this sort of behavior in the server,
> I'm satisfied my distaste for the idea and the reasoning behind it
> is clear now.

For my part, I agree with Greg on this.  While we might want to provide
an option of "go ahead and go past checkpoint timeout if the server gets
too busy to keep up", I don't think it should be the default.

To be honest, I'm also not convinced that this approach is better than
the existing mechanism where the user can adjust checkpoint_timeout to
be higher if they're ok with recovery taking longer and I share Greg's
concern about this backoff potentially running away and causing
checkpoints which never complete or do so far outside the configured
time.
Thanks,
    Stephen

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