Re: missing chunk 0 for toast value ...

On Tue, Oct 25, 2011 at 4:53 PM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:

> Andrew Hammond <andrew(dot)george(dot)hammond(at)gmail(dot)com> writes:
> > On Tue, Oct 25, 2011 at 4:11 PM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
> >> Hmm, that's pretty interesting ... are there any nearby autovacuums of
> >> pg_toast_2619?
>
> > Several, both before and after the error message:
>
> Well, it seems clear that somehow the vacuum deleted a toast tuple that
> the other statement was about to fetch, but it's not clear how this
> could be. The pg_statistic fetch must have come from the planner, which
> should always be called with a transaction snapshot established, and
> that ought to protect it against vacuum deleting anything that could be
> visible to SnapshotNow. Weird.
>
> [ pokes around for a bit ... ] Hmm, can you say how the failing query
> was submitted, exactly? I'm wondering if it came in via simple Query
> (PQexec) or extended-query protocol (anything with parameters).
>

The command was sent from a python via django-1.2.1 using psycopg2-2.2.1

Andrew