Re: optimisation for a table with frequently used query - Mailing list pgsql-general

From Lew
Subject Re: optimisation for a table with frequently used query
Date
Msg-id SeudncuAW8ZfscHbnZ2dnUVZ_ualnZ2d@comcast.com
Whole thread Raw
In response to Re: optimisation for a table with frequently used query  (PFC <lists@peufeu.com>)
Responses Re: optimisation for a table with frequently used query
List pgsql-general
danmcb wrote:
>> SELECT * from my_table where id_1 = x and id_2 = y;
>> Neither id_1 or id_2 or the combination of them is unique. I expect
>> this table to become large over time.

PFC wrote:
> Create an index on (id_1, id_2), or (id_2,id_1).

What are the strengths and weaknesses compared to creating two indexes, one on
each column?

I am guessing that changes to the table are slower with two indexes.  How
could it affect queries?

What if the typical query pattern was more balanced among constraints on one
column, on the other, and on both?

--
Lew

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