Re: slow queries over information schema.tables

On Thu, Dec 6, 2018 at 11:32 AM Tom Lane <tgl@sss.pgh.pa.us> wrote:
> Robert Haas <robertmhaas@gmail.com> writes:
> > I'm not thrilled about depending on sinval without locking,
> > particularly given that my proposal to make sure we
> > AcceptInvalidationMessages() at least once per query was shouted down.
>
> It's fairly hard to imagine practical cases where we'd not call
> AcceptInvalidationMessages at least once per query, so I'm not
> very sure what you're on about.

Unless I'm confused, it happens any time you run a query that only
touches tables using lockmodes previously acquired by the current
transaction.  Like:

BEGIN;
some query;
the same query again;

-- 
Robert Haas
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