On 28 heinä, 21:44, lubos <lubosbou...@gmail.com> wrote: > Hello, > > I have a quite sophisticated database with frequently interconnected tables > and on the top level table, Django produces queries like this: > > SELECT `data_schedule`.`id`, `data_schedule`.`process_id`, > `data_schedule`.`hardware_id`, `data_schedule`.`task_id`, > `data_schedule`.`start`, `data_schedule`.`times`, `data_schedule`.`done`, > `data_process`.`id`, `data_process`.`string_id`, > `data_process`.`operation_id`, `data_string`.`id`, > `data_string`.`immutable`, `data_operation`.`id`, > `data_operation`.`string_id`, T5.`id`, T5.`immutable`, > `data_hardware`.`id`, `data_hardware`.`string_id`, > `data_hardware`.`workspace_id`, `data_hardware`.`warmup`, T7.`id`, > T7.`immutable`, `data_workspace`.`id`, `data_workspace`.`string_id`, > T9.`id`, T9.`immutable`, `data_task`.`id`, `data_task`.`request_id`, > `data_task`.`thread_id`, `data_task`.`amount`, `data_request`.`id`, > `data_request`.`order_id`, `data_request`.`item_id`, > `data_request`.`amount`, `data_order`.`id`, `data_order`.`string_id`, > `data_order`.`subject_id`, `data_order`.`type`, `data_order`.`shipped`, > `data_order`.`paid`, `data_order`.`end`, T13.`id`, T13.`immutable`, > `data_subject`.`id`, `data_subject`.`string_id`, T15.`id`, T15.`immutable`, > `data_item`.`id`, `data_item`.`string_id`, `data_item`.`measure_id`, > `data_item`.`amount`, T17.`id`, T17.`immutable`, `data_measure`.`id`, > `data_measure`.`string_id`, T19.`id`, T19.`immutable`, `data_thread`.`id`, > `data_thread`.`string_id`, T21.`id`, T21.`immutable` FROM `data_schedule` > INNER JOIN `data_process` ON (`data_schedule`.`process_id` = > `data_process`.`id`) INNER JOIN `data_string` ON > (`data_process`.`string_id` = `data_string`.`id`) INNER JOIN > `data_operation` ON (`data_process`.`operation_id` = `data_operation`.`id`) > INNER JOIN `data_string` T5 ON (`data_operation`.`string_id` = T5.`id`) > INNER JOIN `data_hardware` ON (`data_schedule`.`hardware_id` = > `data_hardware`.`id`) INNER JOIN `data_string` T7 ON > (`data_hardware`.`string_id` = T7.`id`) INNER JOIN `data_workspace` ON > (`data_hardware`.`workspace_id` = `data_workspace`.`id`) INNER JOIN > `data_string` T9 ON (`data_workspace`.`string_id` = T9.`id`) INNER JOIN > `data_task` ON (`data_schedule`.`task_id` = `data_task`.`id`) INNER JOIN > `data_request` ON (`data_task`.`request_id` = `data_request`.`id`) INNER > JOIN `data_order` ON (`data_request`.`order_id` = `data_order`.`id`) INNER > JOIN `data_string` T13 ON (`data_order`.`string_id` = T13.`id`) INNER JOIN > `data_subject` ON (`data_order`.`subject_id` = `data_subject`.`id`) INNER > JOIN `data_string` T15 ON (`data_subject`.`string_id` = T15.`id`) INNER > JOIN `data_item` ON (`data_request`.`item_id` = `data_item`.`id`) INNER > JOIN `data_string` T17 ON (`data_item`.`string_id` = T17.`id`) INNER JOIN > `data_measure` ON (`data_item`.`measure_id` = `data_measure`.`id`) INNER > JOIN `data_string` T19 ON (`data_measure`.`string_id` = T19.`id`) INNER > JOIN `data_thread` ON (`data_task`.`thread_id` = `data_thread`.`id`) INNER > JOIN `data_string` T21 ON (`data_thread`.`string_id` = T21.`id`) ORDER BY > `data_schedule`.`id` ASC > > MySQL, however, isn't able to process it and after few minutes it holds all > processor performance. > > I would be glad for any idea.
Are you using select_related()? To me it seems you are just doing too many joins in one query, and MySQL just can't handle it. If select_related is the source of this problem, check if using prefetch_related instead helps. - Anssi -- You received this message because you are subscribed to the Google Groups "Django users" group. To post to this group, send email to django-users@googlegroups.com. To unsubscribe from this group, send email to django-users+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/django-users?hl=en.
