Re: Attaching database

Hi, guys,

On Sun, Oct 25, 2020 at 1:27 PM Peter J. Holzer <hjp-pgsql(at)hjp(dot)at> wrote:
>
> On 2020-10-19 20:21:05 +0200, Pavel Stehule wrote:
> > po 19. 10. 2020 v 20:18 odesílatel Igor Korot <ikorot01(at)gmail(dot)com> napsal:
> > On Mon, Oct 19, 2020 at 12:51 PM Pavel Stehule <pavel(dot)stehule(at)gmail(dot)com>
> > wrote:
> > > It is a different thing - postgresql_fdw does nested connect - it uses
> > > client-server protocol.
> > >
> > > For postgres connect and sql engine process is one entity - and engine is
> > > written without a possibility to reconnect to another database.
> >
> > So if I understand correctly the postgresql_fdw is creating a second
> > connection and uses it as kind of "virtualizing mechanism"
> > in order to give access to the second database.
> >
> >
> > yes - it does new connect to somewhere (local or remote server, but mechanism
> > is absolutely same)
>
> In case this isn't clear:
>
> It is the server (or more specifically, the foreign data wrapper) which
> opens that connection. To the client it looks like it's just accessing a
> normal table within the same database.

Sorry for resurrecting this old thread...
If an attaching the DB creates new connection which will be cmpletely
independent - how the INFORMATION_SCHEMA(dot)table(at)table_catalog
field is handled.

Lets say I open connection to the DB (finance) and then attached another DB
(finance_2021).

So, when I call SELECT table_schema, table_name FROM INFORMATION_SCHEMA.table
I will get all tables from (finance) DB only.
And to get all tables from (finance_2021) I need to make this catalog current
and reissue the query.

Am I right?

Thank you.

>
> hp
>
> --
> _ | Peter J. Holzer | Story must make more sense than reality.
> |_|_) | |
> | | | hjp(at)hjp(dot)at | -- Charles Stross, "Creative writing
> __/ | http://www.hjp.at/ | challenge!"