Re: Read-only access to temp tables for 2PC transactions

On Fri, 24 May 2019 at 18:09, Andres Freund <andres(at)anarazel(dot)de> wrote:

> Hi,
>
> On 2019-05-24 19:37:15 +0300, Konstantin Knizhnik wrote:
> > From my point of view releasing all temporary table locks after
> preparing of
> > 2PC transaction is not technically possible:
> > assume that this transaction has updated some tuples of temporary table
> - them
> > are not visible to other transactions until 2PC is committed,
> > but since lock is removed, other transactions can update the same tuple.
>
> I don't think tuple level actions are the problem? Those doesn't require
> table level locks to be held.
>
> Generally, I fail to see how locks themselves are the problem.

Agreed

> The
> problem are the catalog entries for the temp table, the relation forks,
> and the fact that a session basically couldn't drop (and if created in
> that transaction, use) etc the temp table after the PREPARE.
>

I don't see there is a problem here, but run out of time to explain more,
for a week.

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