Quoting Tom Lane [EMAIL PROTECTED]:
Mischa [EMAIL PROTECTED] writes:
Quoting Tom Lane [EMAIL PROTECTED]:
WHERE a.x b.y AND a.x 42
Out of curiosity, will the planner induce b.y 42 out of this?
No. There's some smarts about transitive equality, but none about
transitive
On Wed, Apr 06, 2005 at 18:09:37 -0400,
Tom Lane [EMAIL PROTECTED] 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
Bruno Wolff III [EMAIL PROTECTED] writes:
Tom Lane [EMAIL PROTECTED] wrote:
Can anyone suggest a more general rule?
I think it makes sense to guess that a smaller fraction of the rows will
be returned when a column value is bounded above and below than if it
is only bounded on one side,
Quoting Tom Lane [EMAIL PROTECTED]:
Yeah, the whole thing is only a heuristic anyway. I've been coming
around to the view that relation membership shouldn't matter, because
of cases like
WHERE a.x b.y AND a.x 42
which surely should be taken as a range constraint.
Out of
Mischa [EMAIL PROTECTED] writes:
Quoting Tom Lane [EMAIL PROTECTED]:
WHERE a.x b.y AND a.x 42
Out of curiosity, will the planner induce b.y 42 out of this?
No. There's some smarts about transitive equality, but none about
transitive inequalities. Offhand I'm not sure if it'd be useful to
