Redmine

Hello,

we have problem with performance in redmine, our environment is:
Environment:
Redmine version 2.4.2.stable
Ruby version 1.9.2
Rails version 3.2.15
Environment production
Database adapter Mysql2

Searching in database is very slow, this is from our slow queries log:

1. Query_time: 14.747925

SELECT DISTINCT `issues`.id FROM `issues` LEFT OUTER JOIN `projects` ON `projects`.`id` = `issues`.`project_id` LEFT OUTER JOIN `journals` ON `journals`.`journalized_id` = `issues`.`id` AND (journals.private_notes = 0 OR (projects.status <> 9 AND projects.id IN (SELECT em.project_id FROM enabled_modules em WHERE em.name='issue_tracking'))) AND `journals`.`journalized_type` = 'Issue' WHERE (projects.status <> 9 AND projects.id IN (SELECT em.project_id FROM enabled_modules em WHERE em.name='issue_tracking')) AND (((LOWER LIKE '%rn4988%') OR (LOWER LIKE '%rn4988%') OR (LOWER LIKE '%rn4988%') OR issues.id IN (SELECT customized_id FROM custom_values WHERE customized_type='Issue' AND customized_id=issues.id AND LOWER LIKE '%rn4988%' AND custom_values.custom_field_id = 9) AND ((1=1) AND (issues.tracker_id IN (SELECT tracker_id FROM custom_fields_trackers WHERE custom_field_id = 9) AND issues.project_id IN (SELECT project_id FROM custom_fields_projects WHERE custom_field_id = 9))) OR issues.id IN (SELECT customized_id FROM custom_values WHERE customized_type='Issue' AND customized_id=issues.id AND LOWER LIKE '%rn4988%' AND custom_values.custom_field_id = 21) AND ((1=1) AND (issues.tracker_id IN (SELECT tracker_id FROM custom_fields_trackers WHERE custom_field_id = 21))) OR issues.id IN (SELECT customized_id FROM custom_values WHERE customized_type='Issue' AND customized_id=issues.id AND LOWER LIKE '%rn4988%' AND custom_values.custom_field_id = 22) AND ((1=1) AND (issues.tracker_id IN (SELECT tracker_id FROM custom_fields_trackers WHERE custom_field_id = 22))) OR issues.id IN (SELECT customized_id FROM custom_values WHERE customized_type='Issue' AND customized_id=issues.id AND LOWER LIKE '%rn4988%' AND custom_values.custom_field_id = 24) AND ((1=1) AND (issues.tracker_id IN (SELECT tracker_id FROM custom_fields_trackers WHERE custom_field_id = 24))) OR issues.id IN (SELECT customized_id FROM custom_values WHERE customized_type='Issue' AND customized_id=issues.id AND LOWER LIKE '%rn4988%' AND custom_values.custom_field_id = 25) AND ((1=1) AND (issues.tracker_id IN (SELECT tracker_id FROM custom_fields_trackers WHERE custom_field_id = 25) AND issues.project_id IN (SELECT project_id FROM custom_fields_projects WHERE custom_field_id = 25))) OR issues.id IN (SELECT customized_id FROM custom_values WHERE customized_type='Issue' AND customized_id=issues.id AND LOWER LIKE '%rn4988%' AND custom_values.custom_field_id = 28) AND ((1=1) AND (issues.tracker_id IN (SELECT tracker_id FROM custom_fields_trackers WHERE custom_field_id = 28) AND issues.project_id IN (SELECT project_id FROM custom_fields_projects WHERE custom_field_id = 28))) OR issues.id IN (SELECT customized_id FROM custom_values WHERE customized_type='Issue' AND customized_id=issues.id AND LOWER LIKE '%rn4988%' AND custom_values.custom_field_id = 29) AND ((1=1) AND (issues.tracker_id IN (SELECT tracker_id FROM custom_fields_trackers WHERE custom_field_id = 29) AND issues.project_id IN (SELECT project_id FROM custom_fields_projects WHERE custom_field_id = 29))) OR issues.id IN (SELECT customized_id FROM custom_values WHERE customized_type='Issue' AND customized_id=issues.id AND LOWER LIKE '%rn4988%' AND custom_values.custom_field_id = 31) AND ((1=1) AND (issues.tracker_id IN (SELECT tracker_id FROM custom_fields_trackers WHERE custom_field_id = 31))) OR issues.id IN (SELECT customized_id FROM custom_values WHERE customized_type='Issue' AND customized_id=issues.id AND LOWER LIKE '%rn4988%' AND custom_values.custom_field_id = 33) AND ((1=1) AND (issues.tracker_id IN (SELECT tracker_id FROM custom_fields_trackers WHERE custom_field_id = 33))) OR issues.id IN (SELECT customized_id FROM custom_values WHERE customized_type='Issue' AND customized_id=issues.id AND LOWER LIKE '%rn4988%' AND custom_values.custom_field_id = 34) AND ((1=1) AND (issues.tracker_id IN (SELECT tracker_id FROM custom_fields_trackers WHERE custom_field_id = 34))) OR issues.id IN (SELECT customized_id FROM custom_values WHERE customized_type='Issue' AND customized_id=issues.id AND LOWER LIKE '%rn4988%' AND custom_values.custom_field_id = 35) AND ((1=1) AND (issues.tracker_id IN (SELECT tracker_id FROM custom_fields_trackers WHERE custom_field_id = 35))) OR issues.id IN (SELECT customized_id FROM custom_values WHERE customized_type='Issue' AND customized_id=issues.id AND LOWER LIKE '%rn4988%' AND custom_values.custom_field_id = 36) AND ((1=1) AND (issues.tracker_id IN (SELECT tracker_id FROM custom_fields_trackers WHERE custom_field_id = 36))) OR issues.id IN (SELECT customized_id FROM custom_values WHERE customized_type='Issue' AND customized_id=issues.id AND LOWER LIKE '%rn4988%' AND custom_values.custom_field_id = 37) AND ((1=1) AND (issues.tracker_id IN (SELECT tracker_id FROM custom_fields_trackers WHERE custom_field_id = 37))) OR issues.id IN (SELECT customized_id FROM custom_values WHERE customized_type='Issue' AND customized_id=issues.id AND LOWER LIKE '%rn4988%' AND custom_values.custom_field_id = 38) AND ((1=1) AND (issues.tracker_id IN (SELECT tracker_id FROM custom_fields_trackers WHERE custom_field_id = 38))) OR issues.id IN (SELECT customized_id FROM custom_values WHERE customized_type='Issue' AND customized_id=issues.id AND LOWER LIKE '%rn4988%' AND custom_values.custom_field_id = 39) AND ((1=1) AND (issues.tracker_id IN (SELECT tracker_id FROM custom_fields_trackers WHERE custom_field_id = 39))) OR issues.id IN (SELECT customized_id FROM custom_values WHERE customized_type='Issue' AND customized_id=issues.id AND LOWER LIKE '%rn4988%' AND custom_values.custom_field_id = 41) AND ((1=1) AND (issues.tracker_id IN (SELECT tracker_id FROM custom_fields_trackers WHERE custom_field_id = 41))) OR issues.id IN (SELECT customized_id FROM custom_values WHERE customized_type='Issue' AND customized_id=issues.id AND LOWER LIKE '%rn4988%' AND custom_values.custom_field_id = 44) AND ((1=1) AND (issues.tracker_id IN (SELECT tracker_id FROM custom_fields_trackers WHERE custom_field_id = 44) AND issues.project_id IN (SELECT project_id FROM custom_fields_projects WHERE custom_field_id = 44))) OR issues.id IN (SELECT customized_id FROM custom_values WHERE customized_type='Issue' AND customized_id=issues.id AND LOWER LIKE '%rn4988%' AND custom_values.custom_field_id = 46) AND ((1=1) AND (issues.tracker_id IN (SELECT tracker_id FROM custom_fields_trackers WHERE custom_field_id = 46))) OR issues.id IN (SELECT customized_id FROM custom_values WHERE customized_type='Issue' AND customized_id=issues.id AND LOWER LIKE '%rn4988%' AND custom_values.custom_field_id = 47) AND ((1=1) AND (issues.tracker_id IN (SELECT tracker_id FROM custom_fields_trackers WHERE custom_field_id = 47))) OR issues.id IN (SELECT customized_id FROM custom_values WHERE customized_type='Issue' AND customized_id=issues.id AND LOWER LIKE '%rn4988%' AND custom_values.custom_field_id = 50) AND ((1=1) AND (issues.tracker_id IN (SELECT tracker_id FROM custom_fields_trackers WHERE custom_field_id = 50))) OR issues.id IN (SELECT customized_id FROM custom_values WHERE customized_type='Issue' AND customized_id=issues.id AND LOWER LIKE '%rn4988%' AND custom_values.custom_field_id = 51) AND ((1=1) AND (issues.tracker_id IN (SELECT tracker_id FROM custom_fields_trackers WHERE custom_field_id = 51))) OR issues.id IN (SELECT customized_id FROM custom_values WHERE customized_type='Issue' AND customized_id=issues.id AND LOWER LIKE '%rn4988%' AND custom_values.custom_field_id = 52) AND ((1=1) AND (issues.tracker_id IN (SELECT tracker_id FROM custom_fields_trackers WHERE custom_field_id = 52))) OR issues.id IN (SELECT customized_id FROM custom_values WHERE customized_type='Issue' AND customized_id=issues.id AND LOWER LIKE '%rn4988%' AND custom_values.custom_field_id = 55) AND ((1=1) AND (issues.tracker_id IN (SELECT tracker_id FROM custom_fields_trackers WHERE custom_field_id = 55))))) ORDER BY issues.id DESC LIMIT 11;

Database has something about 36633 rows, but is it normal to search in them with joins and the value of rows is more than milion?
Second thing I dont understand is that in one search there are two selects, for what?
Is there a thing, that we could use to have searches faster?

Thank you for any answer.