Re: significant slow down with various LIMIT - Mailing list pgsql-performance

"Kevin Grittner" <Kevin.Grittner@wicourts.gov> wrote:

> (3) Try it like this (untested, so you may need to fix it up):
>
> explain analyze
> SELECT core_object.id
>   from (SELECT id, city_id FROM "plugins_guide_address")
>        "plugins_guide_address"
>   JOIN "plugins_plugin_addr"
>     ON ("plugins_plugin_addr"."address_id"
>        = "plugins_guide_address"."id")
>   JOIN "core_object"
>     ON ("core_object"."id" = "plugins_plugin_addr"."oid_id")
>   WHERE "plugins_guide_address"."city_id" = 4535
>   ORDER BY "core_object"."id" DESC
>   LIMIT 4 -- or whatever it normally takes to cause the problem
> ;

Hmph.  I see I didn't take that quite where I intended.
Forget the above and try this:

explain analyze
SELECT core_object.id
  from (SELECT id, city_id FROM "plugins_guide_address"
          WHERE "city_id" = 4535) "plugins_guide_address"
  JOIN "plugins_plugin_addr"
    ON ("plugins_plugin_addr"."address_id"
       = "plugins_guide_address"."id")
  JOIN "core_object"
    ON ("core_object"."id" = "plugins_plugin_addr"."oid_id")
  ORDER BY "core_object"."id" DESC
  LIMIT 4 -- or whatever it normally takes to cause the problem
;

-Kevin