Re: Overwrite pg_catalog? - Mailing list pgsql-general

From Francisco Olarte
Subject Re: Overwrite pg_catalog?
Date
Msg-id CA+bJJbyaCiVXXqoepXEbpqjX+heq3xdNyTFbtq0Zam988utFMQ@mail.gmail.com
Whole thread Raw
In response to Overwrite pg_catalog?  (Juliano <jplinux@protonmail.com>)
Responses Re: Overwrite pg_catalog?
Re: Overwrite pg_catalog?
List pgsql-general
Juliano:

On Thu, Dec 1, 2016 at 12:16 PM, Juliano <jplinux@protonmail.com> wrote:
> I tried to restore pg_catalog to my new database, but the existing
> pg_catalog can't be overwritten or dropped, and postgres auto creates
> pg_catalog when I create a new DB.

This is because, in general, pg_catalog is maintained by DML
statements, restoring it is not going to do what you think.

I.e., if you create a table, a row goes into pg_class, but if you
somehow manage to insert into pg_class a table is not properly created
( more things need to be done ).

Copying pg_catalog from one db to other is like trying to copy the
root dir and FAT from one floppy ( how old fashioned ) to other, it
cannot be done with normal tools and probably won't do what you think
it does.


> So, there is a way to restore the pg_catalog to a new database?

Probably not, but this has the faint smell of http://xyproblem.info/ ,
what are you truing to achieve by doing that?

Francisco Olarte.


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