Re: CLOG extension

On Thu, May 3, 2012 at 3:20 PM, Simon Riggs <simon(at)2ndquadrant(dot)com> wrote:
> Your two paragraphs have roughly opposite arguments...
>
> Doing it every 32 pages would give you 30 seconds to complete the
> fsync, if you kicked it off when half way through the previous file -
> at current maximum rates. So there is utility in doing it in larger
> chunks.

Maybe, but I'd like to try changing one thing at a time. If we change
too much at once, it's likely to be hard to figure out where the
improvement is coming from. Moving the task to a background process
is one improvement; doing it in larger chunks is another. Those
deserve independent testing.

> If it is too slow, we would just wait for sync like we do now.
>
> I think we need another background process since we have both cleaning
> and pre-allocating tasks to perform.

Possibly. I have some fear of ending up with too many background
processes, but we may need them.

--
Robert Haas
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