Re: Query-Planer from 6seconds TO DAYS - Mailing list pgsql-performance

From Kevin Grittner
Subject Re: Query-Planer from 6seconds TO DAYS
Date
Msg-id 20121026153006.306910@gmx.com
Whole thread Raw
In response to Query-Planer from 6seconds TO DAYS  (Böckler Andreas <andy@boeckler.org>)
Responses Re: Query-Planer from 6seconds TO DAYS  (Jeff Janes <jeff.janes@gmail.com>)
List pgsql-performance
ktm@rice.edu wrote:

> You have the sequential_page_cost = 1 which is better than or equal
> to the random_page_cost in all of your examples. It sounds like you
> need a sequential_page_cost of 5, 10, 20 or more.

The goal should be to set the cost factors so that they model actual
costs for you workload in your environment. In what cases have you
seen the sequential scan of a large number of adjacent pages from
disk take longer than randomly reading the same number of pages from
disk? (I would love to see the bonnie++ number for that, if you have
them.)

-Kevin


pgsql-performance by date:

Previous
From: "Kevin Grittner"
Date:
Subject: Re: Query-Planer from 6seconds TO DAYS
Next
From: Jeff Janes
Date:
Subject: Re: Query-Planer from 6seconds TO DAYS