Re: Read-only access to temp tables for 2PC transactions
От
Simon Riggs
Тема
Re: Read-only access to temp tables for 2PC transactions
Дата
Msg-id
CANP8+jJ6of+w3y-2Q6pbguVyvqYSn+Dk5TiXQ_2c8f_r=6gY-Q@mail.gmail.com
Ответ на
Re: Read-only access to temp tables for 2PC transactions (Andres Freund)
Список
Дерево обсуждения
Read-only access to temp tables for 2PC transactions Stas Kelvich <s.kelvich@postgrespro.ru>
Re: Read-only access to temp tables for 2PC transactions Stas Kelvich <s.kelvich@postgrespro.ru>
Re: Read-only access to temp tables for 2PC transactions Simon Riggs <simon@2ndquadrant.com>
Re: Read-only access to temp tables for 2PC transactions Andres Freund <andres@anarazel.de>
Re: Read-only access to temp tables for 2PC transactions Michael Paquier <michael@paquier.xyz>
Re: Read-only access to temp tables for 2PC transactions Simon Riggs <simon@2ndquadrant.com>
Re: Read-only access to temp tables for 2PC transactions Konstantin Knizhnik <k.knizhnik@postgrespro.ru>
Re: Read-only access to temp tables for 2PC transactions Andres Freund <andres@anarazel.de>
Re: Read-only access to temp tables for 2PC transactions Simon Riggs <simon@2ndquadrant.com>
Re: Read-only access to temp tables for 2PC transactions Simon Riggs <simon@2ndquadrant.com>
On Fri, 24 May 2019 at 18:09, Andres Freund <andres@anarazel.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.
Simon Riggs http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
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