Opening an epic in a new tab takes over 13 seconds.

From mysql seems the query is taking about 11s

mysql> SELECT DISTINCT a.id as artifact_id, a.last_changeset_id, t.group_id, t.item_name as keyword, t.id as tracker_id FROM tracker_changeset_value_artifactlink AS artlink JOIN tracker_changeset_value AS cv ON (cv.id = artlink.changeset_value_id) JOIN tracker_artifact AS a ON (a.last_changeset_id = cv.changeset_id) JOIN tracker AS t ON (t.id = a.tracker_id) WHERE artlink.artifact_id = 134153;
+-------------+-------------------+----------+-----------+------------+
| artifact_id | last_changeset_id | group_id | keyword | tracker_id |
+-------------+-------------------+----------+-----------+------------+
| 150589 | 357020 | 506 | product | 3493 |
| 150595 | 375499 | 506 | releases | 3494 |
| 149312 | 346186 | 506 | Operation | 4099 |
+-------------+-------------------+----------+-----------+------------+
3 rows in set (11.20 sec)

After analysis and experiments, we should add the following index:

ALTER TABLE tracker_artifact ADD INDEX idx_changeset_tracker(last_changeset_id, tracker_id);

This will take down the time taken to 0.01 sec.