CI Class manager fails to load - Support and Troubleshooting

CI Class manager fails to load Issue  Description CI Class Manager does not load.

Steps to reproduce Navigate to "Configuration > CI Class Manager". The page does not load. Root Cause 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. Solution Add the following index:

table: sys_schema_change columns: started, finished, duration Additional Info Additional information and related errors can be found on following KBs:

Current indexes on [sys_schema_change] has slow performance when table gets a large number of records which causes long page load times