Re: LIMIT causes planner to do Index Scan using a less optimal index

From: Sherry(dot)CTR(dot)Zhu(at)faa(dot)gov
To: Grzegorz Jaśkiewicz <gryzman(at)gmail(dot)com>
Cc: Joel Jacobson <joel(at)gluefinance(dot)com>, pgsql-performance(at)postgresql(dot)org, pgsql-performance-owner(at)postgresql(dot)org, Robert Haas <robertmhaas(at)gmail(dot)com>
Subject: Re: LIMIT causes planner to do Index Scan using a less optimal index
Date: 2010-04-07 13:22:51
Message-ID: OFCDCC668F.8735D136-ON852576FE.00496440-852576FE.004980E3@faa.gov
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Please just let me know if Postgres can do this kind of index or not.

create index idx1 on tb1(col1, col2)

Then later we can find it is useful or useless.

Thanks much!

Xuefeng Zhu (Sherry)
Crown Consulting Inc. -- Oracle DBA
AIM Lab Data Team
(703) 925-3192

Grzegorz Jaśkiewicz <gryzman(at)gmail(dot)com>
Sent by: pgsql-performance-owner(at)postgresql(dot)org
04/07/2010 09:12 AM

To
Sherry CTR Zhu/AWA/CNTR/FAA(at)FAA
cc
Joel Jacobson <joel(at)gluefinance(dot)com>, pgsql-performance(at)postgresql(dot)org,
Robert Haas <robertmhaas(at)gmail(dot)com>
Subject
Re: [PERFORM] LIMIT causes planner to do Index Scan using a less optimal
index

2010/4/7 <Sherry(dot)CTR(dot)Zhu(at)faa(dot)gov>

Do you mean one index on two columns?

something like this: create index idx1 on tb1(col1, col2);
yup :) It would be quite useless without that feature.
Don't listen to oracle folks, they obviously know not much about products
others than oracle db(s).

--
GJ

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