Re: speed of querry?

Joel Fradkin wrote:
> I must be missing something important, because I am just not seeing why this
> query is slower on a 4 processor 8 gig machine running redhat AS4.

Well, the 4 processors aren't going to help with a single query.
However, assuming the configurations for both machines are comparable,
you shouldn't be seeing a doubling in query-time.

I have, however, spotted something very strange towards the bottom of
each explain:

> Machine 1 my desktop:

> "        ->  Merge Right Join  (cost=0.00..52366.50 rows=190710 width=75)
> (actual time=16.000..1973.000 rows=177041 loops=1)"
> "              Merge Cond: ((("outer".clientnum)::text =
> ("inner".clientnum)::text) AND ("outer".id = "inner".jobtitleid))"


> Test Linux machine:

> "        ->  Merge Right Join  (cost=24825.80..27512.71 rows=176015
> width=75) (actual time=8743.848..9750.775 rows=177041 loops=1)"
> "              Merge Cond: ((("outer".clientnum)::text =
> "inner"."?column10?") AND ("outer".id = "inner".jobtitleid))"

In the first, we match outer.clientnum to inner.clientnum, in the second
it's "?column10?" - are you sure the query was identical in each case.
I'm guessing the unidentified column in query 2 is the reason for the
sort a couple of lines below it, which seems to take up a large chunk of
time.

--
   Richard Huxton
   Archonet Ltd