Re: Wait free LW_SHARED acquisition - v0.9

On 2014-10-30 18:54:57 +0530, Amit Kapila wrote:
> On Thu, Oct 30, 2014 at 5:52 PM, Andres Freund <andres@2ndquadrant.com>
> wrote:
> > On 2014-10-21 12:40:56 +0530, Amit Kapila wrote:
> > > I have ran it for half an hour, but it doesn't came out even after
> > > ~2 hours.  It doesn't get reproduced every time, currently I am
> > > able to reproduce it and the m/c is in same state, if you want any
> > > info, let me know (unfortunately binaries are in release mode, so
> > > might not get enough information).
> >
> > Hm. What commit did you apply the series ontop? I managed to reproduce a
> > hang, but it was just something that heikki had already fixed...
> >
> 
> commit 494affbd900d1c90de17414a575af1a085c3e37a
> Author: Noah Misch <noah@leadboat.com>
> Date:   Sun Oct 12 23:33:37 2014 -0400
> 
> And, I think you are saying that heikki's commit e0d97d has fixed
> this issue, in that case I will check once by including that fix?

Well, the hang I was able to reproduce was originally hanging because of
that. I saw lot of content locks waiting as well, but the "origin" seems
to have a backend waiting for a xloginsert.

The way I could trigger it quite fast was by first running a read/write
pgbench and then switch to a readonly one.

Greetings,

Andres Freund

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