Re: bad plan

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



Julien Cigar <jcigar@xxxxxxxxx> wrote:
 
> I tried to play on the various cost settings but it's doesn't
> change anything, except setting random_page_cost to 1 (which will
> lead to bad plans for other queries, so not a solution)
 
Yeah, you clearly don't have the active portion of your database
fully cached, so you don't want random_page_cost to go as low as
seq_page_cost.
 
Here's one suggestion to try:
 
random_page_cost = 2
cpu_tuple_cost = 0.05
 
I have found that combination to work well for me when the level of
caching is about where you're seeing it.  I am becoming increasingly
of the opinion that the default for cpu_tuple_cost should be higher
than 0.01.
 
Please let us know whether that helps.
 
-Kevin

-- 
Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx)
To make changes to your subscription:
http://www.postgresql.org/mailpref/pgsql-performance


[Postgresql General]     [Postgresql PHP]     [PHP Users]     [PHP Home]     [PHP on Windows]     [Kernel Newbies]     [PHP Classes]     [PHP Books]     [PHP Databases]     [Yosemite]

  Powered by Linux