Re: Scaling shared buffer eviction

On Thu, Sep 11, 2014 at 6:59 PM, Andres Freund <andres(at)2ndquadrant(dot)com>
wrote:
>
> > > We really need a more centralized way to handle error cleanup in
> > > auxiliary processes. The current state of affairs is really pretty
> > > helter-skelter. But for this patch, I think we should aim to mimic
> > > the existing style, as ugly as it is. I'm not sure whether Amit's got
> > > the logic correct, though: I'd agree LWLockReleaseAll(), at a minimum,
> > > is probably a good idea.
> >
> > Code related to bgreclaimer logic itself doesn't take any LWLock, do
> > you suspect the same might be required due to some Signal/Interrupt
> > handling?
>
> I suspect it might creep in at some point at some unrelated place. Which
> will only ever break in production scenarios. Say, a lwlock in in config
> file processing.

Yeah, I suspected the same and checked that path, but couldn't find but
may be in some path it is there as the code has many flows.

> I seem to recall somebody seing a version of a patching
> adding a lwlock there... :). Or a logging hook. Or ...
>
> The savings from not doing LWLockReleaseAll() are nonexistant, so ...

Okay, I shall add it in next version of patch and mention in comments
the reasons quoted by you.

With Regards,
Amit Kapila.
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