Re: Why is checkpoint so costly?

Alvaro, Tom,

>  bgwriter_delay                 | 200
>  bgwriter_maxpages              | 100
>  bgwriter_percent               | 1
>
> Maybe it should be more aggressive.

Yeah, a bgwriter progression is running now.  I don't expect it to make 
much difference.  Most of sync impact is syncing the FS cache, which the 
bgwriter doesn't touch.

> Another thing to blame is the dump-whole-pages-after-checkpoint
> business.  Maybe the load you are seeing is not completely during
> checkpoint, but right after it as well.  How do you tell from the
> results that the checkpoint is complete?

I can't relate that to the performance numbers, unfortunately.  I think 
that the paging is probably the cause, but I don't know what to do about 
it.

-- 
--Josh

Josh Berkus
Aglio Database Solutions
San Francisco