"Joshua D. Drake" <jd(at)commandprompt(dot)com> writes:
> 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'
That's unsurprising. Searching with only a lower-order index column
value seldom wins, 'cause you've got to scan the entire index. The
constraint is irrelevant to this.
regards, tom lane