Re: DROP OWNED BY fails with #53200: ERROR: out of shared memory

On 1/10/22 13:08, David G. Johnston wrote:
> On Mon, Jan 10, 2022 at 12:09 PM Dominique Devienne <ddevienne(at)gmail(dot)com
> <mailto:ddevienne(at)gmail(dot)com>> wrote:
>
> Given |max_locks_per_transaction| * (max_connections
> <https://www.postgresql.org/docs/current/runtime-config-connection.html#GUC-MAX-CONNECTIONS> +
> max_prepared_transactions
> <https://www.postgresql.org/docs/current/runtime-config-resource.html#GUC-MAX-PREPARED-TRANSACTIONS>)
> from
> https://www.postgresql.org/docs/current/runtime-config-locks.html
> <https://www.postgresql.org/docs/current/runtime-config-locks.html>,
> and max_conn being 100, that's not many locks.
>
> Tom wrote "relation" for the number of locks necessary for DROP
> OWNED BY.
> What does it mean in this context? relation = table?
>
>
>
> I'm confused here a bit as well.  The items being talked about are
> tables and indexes, both of which manifest as files on the filesystem.
> But not all relations do (e.g., views).  But if this isn't tied to the
> filesystem then I would expect that other object types, especially
> functions, would require locking as well, but those are decidedly not
> relations.

Pretty sure this is related to:

https://www.postgresql.org/docs/current/explicit-locking.html

In other words to locks on data access.

>
> How do I determine the current value, and change it?
>
>
> https://www.postgresql.org/docs/current/runtime-config.html
> <https://www.postgresql.org/docs/current/runtime-config.html>
> (you already used the SHOW command to determine the current value)
>
> David J.
>

--
Adrian Klaver
adrian(dot)klaver(at)aklaver(dot)com