Rhys Stewart wrote:
> hi all,
> something is not adding up. the following query is taking a long time
> to run.(its still running right now)
>
> select distinct on (prem) prem, num, addy, mynum,myad,ff.address,
> matchtype,
> the_geom
> from daily.recheck2, _sp_myparcels ff
> where
> prem not in (
> select distinct on (prem) prem from daily.recheck2 dr, _sp_myparcels ff
> where ff.address = unabrev
> )
> AND btrim(addy) = btrim(myad)
> AND num = mynum
You're probably better of with a NOT EXISTS here, instead of a NOT IN.
> UNION
And a UNION ALL here, considering you're already using distinct. Or you
could remove the distincts, maybe.
> select distinct on (prem) prem, num, addy, mynum,myad,dr.unabrev,
> matchtype, ff.the_geom
> from daily.recheck2 dr, _sp_myparcels ff--, feeder_polygon
> where ff.address = unabrev
You could have made your query a bit more readable. For example, leaving
the commented out feeder_polygon attribute there could confuse people
who're used to a -- (decrement) operator from other languages.
> the thing is if i run the first query by itself, it takes like about 2
> seconds, and if i run the subquery that takes about 2 seconds also, so
> why (well its now finished, took all of 3.31 minutes) does it take so
> long?
Why do you ask us, instead of the database? EXPLAIN ANALYZE is your (and
our) friend. Without that we can only guess what's slowing down your query.
--
Alban Hertroys
alban@magproductions.nl
magproductions b.v.
T: ++31(0)534346874
F: ++31(0)534346876
M:
I: www.magproductions.nl
A: Postbus 416
7500 AK Enschede
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