Question

I’m working on a fairly standard Django app and lately I’ve been tweaking the admin. While the list views load at reasonable rates, the detail and add views take some ~10 seconds to load.

I’m not exactly sure why it is so– I suspected it had something to do with the database being over queried, and in fact it is. After turning on logging I discovered that the controller is querying for every id in the table:

...
[Mon Oct 22 18:32:52 2012] [error] (0.001) SELECT `courses_course`.`id`, `courses_course`.`semester`,
 `courses_course`.`name`, `courses_course`.`credits`, `courses_course`.`description`, `courses_course
`.`history_id`, `courses_course`.`oldpcr_id`, `courses_course`.`primary_alias_id` FROM `courses_cours
e` WHERE `courses_course`.`id` = 2077 ; args=(2077,)
[Mon Oct 22 18:32:52 2012] [error] (0.000) SELECT `courses_course`.`id`, `courses_course`.`semester`,
 `courses_course`.`name`, `courses_course`.`credits`, `courses_course`.`description`, `courses_course
`.`history_id`, `courses_course`.`oldpcr_id`, `courses_course`.`primary_alias_id` FROM `courses_cours
e` WHERE `courses_course`.`id` = 2078 ; args=(2078,)
[Mon Oct 22 18:32:52 2012] [error] (0.001) SELECT `courses_course`.`id`, `courses_course`.`semester`,
 `courses_course`.`name`, `courses_course`.`credits`, `courses_course`.`description`, `courses_course
`.`history_id`, `courses_course`.`oldpcr_id`, `courses_course`.`primary_alias_id` FROM `courses_cours
e` WHERE `courses_course`.`id` = 2079 ; args=(2079,)
...

Can somebody explain why this is happening? I can’t think of anything at all that might explain it.

Answer 1

I discovered the answer here: Improving Performance of Django ForeignKey Fields in Admin

Because Django lists foreign keys as a select list, it has to query every one. it looks like several solutions are possible, but the simplest is just to set the field to a raw_id field. (And in fact, doing so fixed my problem.)