Re: More 8.2 client issues (Was: [Slow dump?)

Erik Jones <erik@myemma.com> writes:
> Tom Lane wrote:
>> I could see this taking an unreasonable amount of time if you had a huge
>> number of pg_class rows or a very long search_path --- is your database
>> at all out of the ordinary in those ways?
>>
> Well, running "select count(*) from pg_class;" returns 524699 rows

Ouch.

> our search path is the default.  I'd also like to reiterate that \d
> pg_class returns instantly when run from the 8.1.4 psql client connected
> to the 8.2 db.

I think I know where the problem is: would you compare timing of

    select * from pg_class where c.relname ~ '^(pg_class)$';

    select * from pg_class where c.relname ~ '^pg_class$';

Recent versions of psql put parentheses into the regex pattern for
safety in case it's got "|", but I just realized that that probably
confuses the optimizer's check for an indexable regex :-(

However, this only explains slowdown in psql's \d commands, which
wasn't your original complaint ...

            regards, tom lane