Re: Reducing ClogControlLock contention

On 2015-07-01 09:08:11 +0100, Simon Riggs wrote:
> On 1 July 2015 at 09:00, Amit Kapila <amit(dot)kapila16(at)gmail(dot)com> wrote:
>
> > On Tue, Jun 30, 2015 at 12:32 PM, Simon Riggs <simon(at)2ndquadrant(dot)com>
> > a. the semantics of new LWLock (CommitLock) introduced
> > by patch seems to be different in the sense that it is just taken in
> > Exclusive mode (and no Shared mode is required) as per your proposal. We
> > could use existing LWLock APi's, but on the other hand we could even
> > invent new LWLock API for this kind of locking.
> >
>
> LWLock API code is already too complex, so -1 for more changes there

I don't think that's a valid argument. It's better to have the
complexity in one place (lwlock) than have rather similar complexity in
several other places. The clog control lock is far from the only place
that would benefit from tricks along these lines.

Greetings,

Andres Freund