Re: [BUG?] strange behavior in ALTER TABLE ... RENAME TO on inherited columns - Mailing list pgsql-hackers

--On 24. Januar 2010 19:45:33 +0100 Bernd Helmle <mailings@oopsware.de> 
wrote:

>  I don't see where this should be related to the number of tables not
> part of the inheritance tree (or inheritance at all).

To answer that myself: it seems get_attname() introduces the overhead here 
(forgot about that). Creating additional 16384 tables without any 
connection to the inheritance increases the times on my Phenom-II Box to 
round about 2 seconds:


Current -HEAD

bernd=# ALTER TABLE a1 RENAME COLUMN acol1 TO xyz;
ALTER TABLE
Time: 409,045 ms


With KaiGai's recent patch:

bernd=# ALTER TABLE a1 RENAME COLUMN acol1 TO xyz;
ALTER TABLE
Time: 2402,306 ms


-- 
Thanks
Bernd