Re: Separating bgwriter and checkpointer

On Tue, Oct 18, 2011 at 5:39 PM, Robert Haas <robertmhaas(at)gmail(dot)com> wrote:
> On Tue, Oct 18, 2011 at 9:18 AM, Simon Riggs <simon(at)2ndquadrant(dot)com> wrote:
>> Any reason or objection to committing this patch?
>
> Not on my end, though I haven't reviewed it in detail.  One minor note
> - I was mildly surprised to see that you moved this to the
> checkpointer rather than leaving it in the bgwriter:
>
> +       /* Do this once before starting the loop, then just at SIGHUP time. */
> +       SyncRepUpdateSyncStandbysDefined();
>
> My preference would probably have been to leave that in the background
> writer, on the theory that the checkpointer's work is likely to be
> more bursty and therefore it might be less responsive.

That needs to be in the checkpointer because that is the process that
shuts down last.

The bgwriter is now more like the walwriter. It shuts down early in
the shutdown process, while the checkpointer is last out.

So it wasn't preference, it was a requirement of the new role definitions.

--
 Simon Riggs                   http://www.2ndQuadrant.com/
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