Re: [SQL] what is "cost"? - Mailing list pgsql-sql

From Bruce Momjian
Subject Re: [SQL] what is "cost"?
Date
Msg-id 199904232129.RAA14632@candle.pha.pa.us
Whole thread Raw
In response to Re: [SQL] what is "cost"?  (Gregory Holston <holston@itd.nrl.navy.mil>)
List pgsql-sql
> >     The cost value is only meaningful to the optimizer in comparing various
> >     query plans.
> > 
> I got the 72.98 on this table while doing a simple "select * from 
> publication" meanwhile I got nothing higher than 4 on any other table. Is this 
> indicative of a problem?

No.  It means the optimizer thinks it is going to have to do more work
to complete the query.  All other methods it used to complete the query
had a higher cost.  It is related to the number of rows in the table,
the indexes available, sorts needed, joins, etc.

--  Bruce Momjian                        |  http://www.op.net/~candle maillist@candle.pha.pa.us            |  (610)
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