Re: [GENERAL] Cost: Big Tables vs. Organized Separation of Data

Bruce Momjian <maillist@candle.pha.pa.us>

From: Bruce Momjian <maillist@candle.pha.pa.us>
To: bobd@palaver.net (Bob Dusek)
Cc: pgsql-general@postgreSQL.org
Date: 1999-02-03T03:57:01Z
Lists: pgsql-general
> 1. If I re-organize the data, I would be able to perform my queries 
> without executing joins on multiple tables per query.
> 
> 2. As I re-organize the data, the database becomes less and less
> intuitive and (seemingly) less "normal".  
> 
> So, I guess my question is:  how costly are joins?  I've heard that
> Postgres pretty much "pukes" (in terms of speed) when you're trying 
> to do anything more than 6 table joins in one query.  This leads
> me to believe that joins are fairly costly... ????  
> 
> Does anyone have any words of advice for me as I battle this?

We are working speeding up large table joins right now.  Try doing SET
GEQO to set the value lower and see if that helps.

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