Hi,

you can only run inquires now on information_schema for the database you are connected to.

If you are looking/searching in pg_database though, you can information globally.

Something changed recently (I am using Dbeaver); I was able to attach to a single database and see all my databases; run queries, etc.

With the latest update, now you have to have a separate connection to each database.

Navicat now does the same thing, so my thinking is they must have changed the drivers.

Regards,

On 10/15/22 02:06, Julien Rouhaud wrote:
Hi,

On Fri, Oct 14, 2022 at 11:16:44PM -0500, Igor Korot wrote:
Sorry for resurrecting this old thread...
If an attaching the DB creates new connection which will be cmpletely
independent - how the INFORMATION_SCHEMA.table@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?
No.  In postgres, databases are completely disjoint containers and once you
have a connection on a given database it will stay on that database, there's no
way around that.

Using postgres_fdw allows you to create a local table that will point to
another table, possibly on another database or even another server, but it will
still be a (foreign) table, that has to be created in the current database in
the schema of your choice.

Depending on your use case, maybe what you could do is create a finance_2021
schema, and create all the foreign tables you need in that schema pointing to
the finance_2021 database.  Any table existing in both "finance" and
"finance_2021" will then be visible in information_schema.tables, with a
different table_schema.  If you have multiple schemas in each database, then
find a way to make it work, maybe adding a _2021 suffix on each schema or
something like that.

You can then maybe use the search_path (see
https://www.postgresql.org/docs/current/ddl-schemas.html#DDL-SCHEMAS-PATH) to
use by default one of the set of tables rather than the other.  But in any
case, it's only a workaround that has to be implemented on your client, as you
will always be connected on the same database, and see both set of object in
information_schema.


--
Alex Theodossis
a...@dossi.info
347-514-5420



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