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Re: Postgres seems to use indexes in the wrong order - Mailing list pgsql-general

From Tim Uckun
Subject Re: Postgres seems to use indexes in the wrong order
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Msg-id CAGuHJrM-uOEfb0xEyqAR5jQ1KPAYhoaeWk=anqa=UiNBq91VLw@mail.gmail.com
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In response to Re: Postgres seems to use indexes in the wrong order  (Sameer Kumar <sameer.kumar@ashnik.com>)
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The effective_cache_size is one gig. The others are not set so therefore the default.



On Sun, Jan 25, 2015 at 6:08 AM, Sameer Kumar <sameer.kumar@ashnik.com> wrote:

On Fri, Jan 23, 2015 at 3:04 PM, Tim Uckun <timuckun@gmail.com> wrote:
Take a look at this explain

http://explain.depesz.com/s/TTRN

​Adding some info on the query and table structure (and indexes) would be helpful here.​
 


The final number of records is very small but PG is starting out with a massive number of records and then filtering most of them out.

I don't want to really force pg to always use the same index because in some cases this strategy would win but I am wondering if there is anything I need to do in order to get the planner to make better decisions.


​What are the values for below parameters-

- random_page_cost
- seq_page_cost
​- effective_cache_size

 
I already did an analyze on the table.



Best Regards,

Sameer Kumar | Database Consultant

ASHNIK PTE. LTD.

101 Cecil Street, #11-11 Tong Eng Building, Singapore 069533

M: +65 8110 0350  T: +65 6438 3504 | www.ashnik.com

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