Re: Query with rightmost function does not use index

From: pasman pasmański <pasman(dot)p(at)gmail(dot)com>
To: pgsql-general(at)postgresql(dot)org
Subject: Re: Query with rightmost function does not use index
Date: 2011-08-08 05:31:56
Message-ID: CAOWY8=Z-B7k5+MFoD+t743Kaxz-gZhuO4da9QfuSekT+2FWU5Q@mail.gmail.com
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Here may be other problem.
Show us the result of EXPLAIN Analyze.

2011/8/8, Pavel Stehule <pavel(dot)stehule(at)gmail(dot)com>:
> Hello
>
> use a functional index
>
> http://www.postgresql.org/docs/8.4/interactive/indexes-expressional.html
>
> Regards
>
> Pavel Stehule
>
> 2011/8/8 - - <loh(dot)law(at)hotmail(dot)com>:
>> For a table where column col has an index, the query:
>>      SELECT ... FROM ... WHERE col = MD5('')
>> doesn't seem to use an index but
>>      SELECT ... FROM ... WHERE col = 'd41d8cd98f00b204e9800998ecf8427e'
>> does.
>>
>> Is this a gotcha?
>> I'm using PostgreSQL 8.4.8 on i686-pc-linux-gnu, compiled by GCC
>> gcc-4.5.real (Ubuntu/Linaro 4.5.2-8ubuntu4) 4.5.2, 32-bit
>>
>>
>>
>
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--
------------
pasman

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