Re: [GENERAL] Cost: Big Tables vs. Organized Separation of Data - Mailing list pgsql-general

From Bruce Momjian
Subject Re: [GENERAL] Cost: Big Tables vs. Organized Separation of Data
Date
Msg-id 199902030357.WAA19925@candle.pha.pa.us
Whole thread Raw
In response to Cost: Big Tables vs. Organized Separation of Data  (Bob Dusek <bobd@palaver.net>)
List 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.

--
  Bruce Momjian                        |  http://www.op.net/~candle
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  +  If your life is a hard drive,     |  830 Blythe Avenue
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