Re: update ALTER TABLE with ATTACH PARTITION lock mode

On 2019-Oct-28, Michael Paquier wrote:

> On Sun, Oct 27, 2019 at 07:12:07PM -0500, Justin Pryzby wrote:
> > commit #898e5e32 (Allow ATTACH PARTITION with only ShareUpdateExclusiveLock)
> > updates ddl.sgml but not alter_table.sgml, which only says:
> >
> > https://www.postgresql.org/docs/12/release-12.html
> > |An ACCESS EXCLUSIVE lock is held unless explicitly noted.
>
> + <para>
> + Attaching a partition acquires a <literal>SHARE UPDATE EXCLUSIVE</literal>
> + lock on the partitioned table, in addition to an
> + <literal>ACCESS EXCLUSIVE</literal> lock on the partition.
> + </para>
> Updating the docs of ALTER TABLE sounds like a good idea. This
> sentence looks fine to me. Perhaps others have suggestions?

Doesn't the command also acquire a lock on the default partition if
there is one? It sounds worth noting.

> > Find attached patch, which also improve language in several related places.
>
> Not sure that these are actually improvements.

I think some of them (most?) are clear improvements.

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Álvaro Herrera https://www.2ndQuadrant.com/
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