From: | Alvaro Herrera <alvherre(at)2ndquadrant(dot)com> |
---|---|
To: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
Cc: | pgsql-committers(at)postgresql(dot)org |
Subject: | Re: pgsql: Add isolationtester spec for old heapam.c bug |
Date: | 2016-02-29 17:44:06 |
Message-ID: | 20160229174405.GA282394@alvherre.pgsql |
Views: | Raw Message | Whole Thread | Download mbox | Resend email |
Thread: | |
Lists: | pgsql-committers pgsql-hackers |
Tom Lane wrote:
> I wrote:
> > Alvaro Herrera <alvherre(at)alvh(dot)no-ip(dot)org> writes:
> >> Add isolationtester spec for old heapam.c bug
>
> > Hmmm ....
>
> > http://buildfarm.postgresql.org/cgi-bin/show_log.pl?nm=spoonbill&dt=2016-02-27%2000%3A00%3A06
>
> > This failure looks a lot like the timing-related problems I was chasing
> > last week with deadlock-hard on the CLOBBER_CACHE_ALWAYS critters.
> > spoonbill isn't CLOBBER_CACHE_ALWAYS, but it uses some weird malloc debug
> > stuff that slows it down by similar orders of magnitude. You seem to need
> > to think about how to make this test less timing-dependent.
>
> The plot thickens:
>
> http://buildfarm.postgresql.org/cgi-bin/show_log.pl?nm=guaibasaurus&dt=2016-02-29%2016%3A17%3A01
>
> guaibasaurus is not a particularly slow machine, and it's not using any
> special build flags AFAICT. So I'm not sure what to make of this case,
> except that it proves the timing problem can manifest on normal builds.
Hmm, I suppose I could fix this by using three different advisory locks
rather than a single one. (My assumption is that the timing dependency
is the order in which the backends are awakened when the advisory lock
is released.) I would release the locks one by one rather than all
together.
--
Álvaro Herrera http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
From | Date | Subject | |
---|---|---|---|
Next Message | Tom Lane | 2016-02-29 18:08:42 | Re: pgsql: Add isolationtester spec for old heapam.c bug |
Previous Message | Tom Lane | 2016-02-29 17:06:56 | Re: pgsql: Add isolationtester spec for old heapam.c bug |
From | Date | Subject | |
---|---|---|---|
Next Message | Robert Haas | 2016-02-29 17:46:10 | Re: WIP: Upper planner pathification |
Previous Message | Robert Haas | 2016-02-29 17:40:35 | Re: Speed up Clog Access by increasing CLOG buffers |