Re: StandbyAcquireAccessExclusiveLock doesn't necessarily

On 2018-09-11 12:18:59 -0400, Tom Lane wrote:
> Andres Freund <andres(at)anarazel(dot)de> writes:
> > On 2018-09-11 12:03:44 -0400, Tom Lane wrote:
> >> If the startup process has acquired enough AELs to approach locktable
> >> full, any concurrent pg_dump has probably failed already, because it'd
> >> be trying to share-lock every table and so would have a huge conflict
> >> cross-section; it's hard to believe it wouldn't get cancelled pretty
> >> early in that process. (Again, if you think this scenario is probable,
> >> you have to explain the lack of field complaints.)
>
> > I was thinking of the other way round - there's a running pg_dump and
> > then somebody does a bit of DDL (say a DROP SCHEMA CASCADE in a
> > multi-tenant scenario).
>
> Doesn't matter: startup would hit a lock conflict and cancel the pg_dump
> to get out of it, long before approaching locktable full.

Only if all that's happening in the same database, which is far from a
given.

Greetings,

Andres Freund