Re: Speeding up Query

From: Alexander Lohse <al(at)humantouch(dot)de>
To: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Cc: pgsql-general(at)postgresql(dot)org
Subject: Re: Speeding up Query
Date: 2001-05-14 16:00:36
Message-ID: p05100300b725af0d9fff@[192.168.0.89]
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>This is pretty horrid: you are generating a cross product of
>events * event_ref * teams * orgs * pers and then selecting rows
>multiple times out of that very large set. No wonder you lost
>patience even with a small test database. I think you wanted
>something like
>
>...
>INTERSECT (
>
>select events.id from events where
>(lower(events.head) like '%web%'
> or lower(events.search) like '%web%'
> or lower(events.ort) like '%web%'
> or lower(events.text) like '%web%'
>
>union
>
>select teams.id from teams where
>lower(teams.name) like '%web%'
>
>union
>

Hi Tom,

this thing is a bit more complicated.

event_ref is the table containing the relations events <-> teams (One
event/multiple Teams)
Spoken: Teams or Persons organise Events,
that's what: (events.id = event_ref.event_id and event_ref.ref_id =
teams.id) is for.

Now, this search wants to be able to find all events that are
organised by teams, pers, orgs where teams,p,o name contains
"search_string".

But maybe you already brought the idea to me! Instead of using
pleanty of ORs I should try using plenty UNIONs.

Would it also possible to make multiple INTERSECTS?
How do these operate on each other, do I also use parentheses?

I am bit in a hurry, right in the moment that why I write stenograph! ;-)

Thank you in advance,

Alex

--
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Alexander Lohse
Tel: (038374) 75211
Fax: (038374) 75223
eMail: al(at)humantouch(dot)de
http://www.humantouch.de

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