On Wed, Apr 06, 2005 at 06:35:10PM -0400, Tom Lane wrote:
> "Jim C. Nasby" <[EMAIL PROTECTED]> writes:
> > On Wed, Apr 06, 2005 at 06:09:37PM -0400, Tom Lane wrote:
> >> Can anyone suggest a more general rule? Do we need for example to
> >> consider whether the relation membership is the same in t
On Wed, 2005-04-06 at 18:09 -0400, Tom Lane wrote:
> I wrote:
> > Arjen van der Meijden <[EMAIL PROTECTED]> writes:
> >> SELECT COUNT(*) FROM
> >> data_main AS dm,
> >> postcodes AS p
> >> WHERE dm.range BETWEEN p.range_from AND p.range_till
>
> > Planner error ... because it doesn't have any good
John A Meinel <[EMAIL PROTECTED]> writes:
> Actually, I think he was saying do a nested loop, and for each item in
> the nested loop, re-evaluate if an index or a sequential scan is more
> efficient.
> I don't think postgres re-plans once it has started, though you could
> test this in a plpgsql f
"Jim C. Nasby" <[EMAIL PROTECTED]> writes:
> On Wed, Apr 06, 2005 at 06:09:37PM -0400, Tom Lane wrote:
>> Can anyone suggest a more general rule? Do we need for example to
>> consider whether the relation membership is the same in two clauses
>> that might be opposite sides of a range restriction?
On Wed, Apr 06, 2005 at 06:09:37PM -0400, Tom Lane wrote:
> Can anyone suggest a more general rule? Do we need for example to
> consider whether the relation membership is the same in two clauses
> that might be opposite sides of a range restriction? It seems like
>
> a.x > b.y AND a.x < b
I wrote:
> Arjen van der Meijden <[EMAIL PROTECTED]> writes:
>> SELECT COUNT(*) FROM
>> data_main AS dm,
>> postcodes AS p
>> WHERE dm.range BETWEEN p.range_from AND p.range_till
> Planner error ... because it doesn't have any good way to estimate the
> number of matching rows, it thinks that way
