Re: [RFC] Should smgrtruncate() avoid sending sinval message for temp relations

On 2014-07-26 20:20:05 +0200, Andres Freund wrote:
> On 2014-07-26 13:58:38 -0400, Tom Lane wrote:
> 
> > Andres Freund <andres@2ndquadrant.com> writes:
> > > That'd require either renegging on SA_RESTART or
> > > using WaitLatchOrSocket() and nonblocking send/recv.
> > 
> > Yeah, I was wondering about using WaitLatchOrSocket for client I/O too.
> > We already have a hook that lets us do the actual recv even when using
> > OpenSSL, and in principle that function could do interrupt-service-like
> > functions if it got kicked off the recv().
> 
> I've started playing with this. Looks clearly worthwile.
> 
> I think if we do it right we pretty much can get rid of the whole
> prepare_for_client_read() machinery and handle everything via
> ProcessInterrupts(). EnableCatchupInterrupt() et al don't really fill me
> with joy.

One thing I am wondering about around this is: Why are we only
processing catchup events when DoingCommandRead? There's other paths
where we can wait for data from the client for a long time. Obviously we
don't want to process async.c stuff from inside copy, but I don't see
why that's the case for sinval.c.

Greetings,

Andres Freund

-- Andres Freund                       http://www.2ndQuadrant.com/PostgreSQL Development, 24x7 Support, Training &
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