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Re: Constraint exclusion oddity with composite index

From: "Joshua D(dot) Drake" <jd(at)commandprompt(dot)com>
To: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Cc: PostgreSQL-development <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: Constraint exclusion oddity with composite index
Date: 2007-06-01 21:03:07
Message-ID: 4660898B.7000909@commandprompt.com (view raw or flat)
Thread:
Lists: pgsql-hackers
Tom Lane wrote:
> "Joshua D. Drake" <jd(at)commandprompt(dot)com> writes:
>> Assume the following:
>> index on: (id, adate)
>> constraint CHECK(adate > '01-01-2007' AND adate < '04-01-2007');
> 
>> The planner will not use the index listed above.
> 
> For what?

select adate from parent where adate = '01-25-2007'

For example.

Joshua D. Drake



> 
> 			regards, tom lane
> 
> ---------------------------(end of broadcast)---------------------------
> TIP 9: In versions below 8.0, the planner will ignore your desire to
>        choose an index scan if your joining column's datatypes do not
>        match
> 


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