Re: toast tables on system catalogs

On Mon, Sep 5, 2011 at 1:01 PM, Bruce Momjian <bruce(at)momjian(dot)us> wrote:
> Alvaro Herrera wrote:
>> 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?)
>
> Did we decide on this?  Is it a TODO?

Uh, maybe. It's not really clear that there's enough benefit here to
justify someone spending time on it. If no one is feeling motivated
maybe we should just let it go...

--
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
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