Gregory Stark <[EMAIL PROTECTED]> writes:
> Tom Lane <[EMAIL PROTECTED]> writes:
>> only the a = 5 clause would be used with the index. As of 8.1 it will
>> consider using nonconsecutive index columns
> Really? Is this the "skip scan" plan people were pining for?
No, there's no skip scan, it jus
Tom Lane <[EMAIL PROTECTED]> writes:
> Before (if memory serves) 8.1, the planner would only consider leading
> index columns as potential indexscan qualifiers. So given
>
> where a = 5 and c = 4;
>
> only the a = 5 clause would be used with the index. As of 8.1 it will
> consider using
[EMAIL PROTECTED] writes:
> Suppose I have an index on 5 columns (A, B, C, D, E).
> If my WHERE clause is not in that order, will the optimizer reorder
> them as necessary and possible?
Yes, the optimizer understands about commutativity/associativity of
AND and OR ;-)
> If I don't specify co
Suppose I have an index on 5 columns (A, B, C, D, E).
If my WHERE clause is not in that order, will the optimizer reorder
them as necessary and possible?
WHERE A=1 AND C=3 AND B=2 AND E=5 AND D=4
Obviously it can't reorder them in all cases:
WHERE A=1 AND (C=3 OR B=2) AND (E=5 OR D
