   it is set to zero (the default setting) then a suitable
        value is chosen based on <TT
CLASS="VARNAME"
>geqo_effort</TT
> and
        the number of tables in the query.
       </P
></DD
><DT
><A
NAME="GUC-GEQO-GENERATIONS"
></A
><TT
CLASS="VARNAME"
>geqo_generations</TT
> (<TT
CLASS="TYPE"
>integer</TT
>)</DT
><DD
><P
>        Controls the number of generations used by GEQO, that is
        the number of iterations of the algorithm.  It must
        be at least one, and useful values are in the sam