CI Class Manager does not load.
Steps to reproduce
- Navigate to "Configuration > CI Class Manager".
- The page does not load.
The CI Class Manager checks if there is an upgrade in progress before loading. The sys_schema_change is queried as part of this check. It may take a long time to check on upgrade status if the table is very large and does not have an index on sys_schema_change(started, finished, duration).
This is also seen on PRB1255465.
To confirm this is the root cause:
- Navigate to "System Diagnostics > Upgrade Monitor".
- Upgrade Monitor will not load either, as it performs the same query.
Add the following index:
- table: sys_schema_change
- columns: started, finished, duration
Additional information and related errors can be found on following KBs: