Re: BIG Joins

In article <305so3$50k_at_panix.com> janest_at_panix.com (John Anest) writes:
>In article <9407131738.PN05420_at_LL.MIT.EDU> forgy_at_ll.mit.edu (James Forgy) writes:
>>In article <Csw32B.Ju7_at_Unify.com> jde_at_Unify.com (Jeff Evarts) writes:
>>>From: jde_at_Unify.com (Jeff Evarts)
>>>Subject: BIG Joins
>>>Date: Wed, 13 Jul 1994 17:25:23 GMT
 

>>>I`m curious... how many people out there know of a runtime environment
>>>where a "common" operation on a database involves a join of more than,
>>>say, 5 tables?
>------------
>
>>I have wrote a 7-Way Join with a Union on a 600,000 row table and it only took
>>7 seconds to run.
>
> Unless I'm mistaken, a Union just lumps result sets together. I don't
>think its a join!
>
>John

With a query tool (called ReportEngine from TechGnosis) I recently asked for a certain report which was translated into a query with a join for 10 (yes TEN) tables ! Depending on the load on the ingres server it takes about 10 minutes to run or it takes about 10 minutes to choke on (not enough memory for the query optimizer). Some where in the near future I'm going to upload the same table structure and data into an Oracle database and have a look on the performance of Oracle on this query.

Gerrit.

-- 
Gerrit Cap				
Vlaamse Televisie Maatschappij N.V.		e-mail :   gerrit_at_vtm.be
Medialaan 1					fax    : +32 2 253.12.21
B-1800 Vilvoorde Belgium			voice  : +32 2 255.38.72