--On 24. Januar 2010 08:37:13 -0500 Robert Haas <robertmh...@gmail.com>
wrote:
I agree - the requirements here are much looser than for, say, SELECT
or UPDATE. But it still has to not suck.
Yeah, i think the meaning of "suck" can be much weakier than for a DML
command. However, if it would degrade the performance of a formerly well
running command in a way, that it would be unusable, that would be annoying.
I think the problem case here might be something like this... create
ten tables A1 through A10. Now create 10 more tables B1 through B10
each of which inherits from all of A1 through A10. Now create 10 more
tables C1 through C10 that inherit from B1 through B10. Now create
1000 tables D1 through D1000 that inherit from C1 through C10. Now
drop a column from A1.
Er... rename a column from A1, not drop.
Did that with a crude pl/pgsql script, and got the following numbers:
Current -HEAD:
Phenom-II 2.6 GHz: Time: 282,471 ms
MacBook: Time: 499,866 ms
With KaiGais recent patch (which covers the TYPE case, too):
Phenom-II 2.6 GHz: Time: 476,800 ms
MacBook: Time: 753,161 ms
--
Thanks
Bernd
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