Re: Would a BGW need shmem_access or database_connection to enumerate databases?

On 2017-11-29 18:23:40 -0500, Chapman Flack wrote:
> On 11/29/2017 05:54 PM, Michael Paquier wrote:
>
> > Yes. That's actually what the autovacuum launcher does. It connects
> > using InitPostgres(NULL, InvalidOid, NULL, NULL), and then scans
> > pg_database to fetch a list (see get_database_list).
>
> Thanks! It looks like if get_database_list were not static, it
> would be just the thing I'm looking for.
>
> Would an SPI query of pg_database also work, in the
> bgw-connected-to-null-dbname context? I'm just wondering if
> that might be clearer/fewer LOC than just copying the lower-level
> approach from get_database_list.

SQL won't really work in a non-database connected context.