Re: query execution time - Mailing list pgsql-general

From preetika tyagi
Subject Re: query execution time
Date
Msg-id AANLkTimQjE1cMGLPVDH+SNsH4A+Mwx2+_T+rQ1dJAkhV@mail.gmail.com
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In response to Re: query execution time  (Scott Ribe <scott_ribe@elevated-dev.com>)
Responses Re: query execution time  (Scott Ribe <scott_ribe@elevated-dev.com>)
List pgsql-general
Thank you, Scott!
I tried running the same query after reboot and back-to-back, it was taking less time in both the cases. It means the problem is something else.

Can there be a reason which is more hardware/operating system specific and due to which the behavior is not uniform?

Preetika

On Mon, Mar 21, 2011 at 9:06 AM, Scott Ribe <scott_ribe@elevated-dev.com> wrote:
On Mar 21, 2011, at 9:55 AM, preetika tyagi wrote:

> For example, if A is 15 minutes, then B is 1.5 hrs.

Well, considering that random disk access is on the order of 10,000 times slower than RAM...

But you can answer the question yourself by comparing the query run against cold caches (after a reboot, or various command-line tricks to purge cache) vs against warm caches (twice back-to-back).

--
Scott Ribe
scott_ribe@elevated-dev.com
http://www.elevated-dev.com/
(303) 722-0567 voice





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