It's enabled by default. You can set the threshold to something other than 12 if you want to: http://www.postgresql.org/docs/9.1/static/runtime-config-query.htm

It's enabled by default. You can set the threshold to something other than 12 if you want to: http://www.postgresql.org/docs/9.1/static/runtime-config-query.html#RUNTIME-CONFIG-QUERY-GEQO http://www.postgresql.org/docs/9.1/static/runtime-config-que...