Re: toast tables on system catalogs

Excerpts from Tom Lane's message of mar mar 01 19:03:35 -0300 2011:
> Alvaro Herrera <alvherre(at)alvh(dot)no-ip(dot)org> writes:
> > Strangely, we made pg_database have a toast table, and the only reason
> > for this is datacl. Should we create toast tables for the remaining
> > catalogs?
>
> As I commented on your blog, this is nonsense. pg_database has a TOAST
> table becase we thought it might need one for datconfig[]. Now that
> that's gone, it'd be consistent to remove the toast table, but it didn't
> occur to us to do that.

Yeah, it occured to me to troll the git logs just after sending the
email and I promptly noticed the bug in my conclusion -- there was no
datacl back then; and pg_db_role_settings is very new.

> aclitem entries wide enough to need toasting are going to suck for all
> sorts of reasons (IIRC there are some O(N^2) algorithms in there, not
> to mention the cost of pulling in entries from a toast table on every
> access) so I am not excited about encouraging people to use them.

I agree on not supporting large numbers of privileges, though the error
message leaves a bit to be desired.

Should we remove the toast table declaration for pg_database?

(BTW with the relmapper mechanism, do we still need to declare the toast
table OIDs?)

--
Álvaro Herrera <alvherre(at)commandprompt(dot)com>
The PostgreSQL Company - Command Prompt, Inc.
PostgreSQL Replication, Consulting, Custom Development, 24x7 support