Re: performance problem aftrer update from 7.1 to 7.4.2

["Development - multi.art.studio" <dev.null@multiartstudio.com>]

Hello, and thanks for reading

Richard Huxton wrote:

Something funny here - notice the width of newsletter (84) in the old version 
against the width in the new one (610).

  

hmmm, but why? the old mcms09 database is still growing and productive, and 7.4 is not updated and only for testing at this time.
as i do the tests, both database contents where the same, but the old was still used by other users.
 i do some additional tests, and a simple query explain in 7.4 gives much bigger values than in 7.1,
i tried vacuum, but nothing deleteted because everything grows....and only sometimes one
or two entries are deleted....,
last but not least i also reindex the new database, but indexes where all ok, and there are no problems with that (not looking on the final db design)

what happens that 7.4 will took so much time, and width for its querys? (really, i read that pg74 would speed up 2 or 3 times....if good db design) i didnt change anything on the tables.

thanks for any help,
volker

ps:mcms09 will be availablke for download in a few weeks, using pgsql as a backend :)

7.1:
mcms09=> explain select * from newsletter where site_id='m000000-970' order
by date desc,id desc limit 10; NOTICE:  QUERY PLAN:
Limit  (cost=9.26..9.26 rows=7 width=84)
    

7.4.2:
mcms=# explain select * from newsletter where site_id='m000000-970' order
by date desc,id desc limit 10; QUERY PLAN
---------------------------------------------------------------------------
------------------------------ Limit  (cost=17.78..17.81 rows=10 width=610)
   ->  Sort  (cost=17.78..17.81 rows=11 width=610)