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Thread: What is Cost 100 in stored procedure

What is Cost 100 in stored procedure

From
Yan Cheng Cheok
Date:
May I know what is the meaning of Cost 100, at the end of stored procedure?

....
END;$BODY$
  LANGUAGE 'plpgsql' VOLATILE
  COST 100;
ALTER FUNCTION create_tables() OWNER TO postgres;

Thanks and Regards
Yan Cheng CHEOK

Re: What is Cost 100 in stored procedure

From
Rob Wultsch
Date:
On Tue, Jan 12, 2010 at 8:06 PM, Yan Cheng Cheok <yccheok@yahoo.com> wrote:
> May I know what is the meaning of Cost 100, at the end of stored procedure?
>
> ....
> END;$BODY$
>  LANGUAGE 'plpgsql' VOLATILE
>  COST 100;
> ALTER FUNCTION create_tables() OWNER TO postgres;
>
> Thanks and Regards
> Yan Cheng CHEOK
>


"execution_cost

    A positive number giving the estimated execution cost for the
function, in units of cpu_operator_cost. If the function returns a
set, this is the cost per returned row. If the cost is not specified,
1 unit is assumed for C-language and internal functions, and 100 units
for functions in all other languages. Larger values cause the planner
to try to avoid evaluating the function more often than necessary. "

http://www.postgresql.org/docs/8.4/interactive/sql-createfunction.html


--
Rob Wultsch
wultsch@gmail.com