Re: Constraint exclusion oddity with composite index

Joshua D. Drake <jd@commandprompt.com>

From: "Joshua D. Drake" <jd@commandprompt.com>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: PostgreSQL-development <pgsql-hackers@postgresql.org>
Date: 2007-06-01T21:03:07Z
Lists: pgsql-hackers
Tom Lane wrote:
> "Joshua D. Drake" <jd@commandprompt.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
> 


-- 

       === The PostgreSQL Company: Command Prompt, Inc. ===
Sales/Support: +1.503.667.4564 || 24x7/Emergency: +1.800.492.2240
Providing the most comprehensive  PostgreSQL solutions since 1997
              http://www.commandprompt.com/

Donate to the PostgreSQL Project: http://www.postgresql.org/about/donate
PostgreSQL Replication: http://www.commandprompt.com/products/