CI Class manager fails to loadDescription<!-- div.margin{ padding: 10px 40px 40px 30px; } table.tocTable{ border: 1px solid; border-color:#E0E0E0; background-color: rgb(245, 245, 245); padding-top: .6em; padding-bottom: .6em; padding-left: .9em; padding-right: .6em; } table.noteTable{ border:1px solid; border-color:#E0E0E0; background-color: rgb(245, 245, 245); width: 100%; border-spacing:2; } table.internaltable { white-space:nowrap; text-align:left; border-width: 1px; border-collapse: collapse; font-size:14px; width: 85%; } table.internaltable th { border-width: 1px; padding: 5px; border-style: solid; border-color: rgb(245, 245, 245); background-color: rgb(245, 245, 245); } table.internaltable td { border-width: 1px; padding: 5px; border-style: solid; border-color: #E0E0E0; color: #000000; } table tr td { padding: 15px; } .title { color: #D1232B; font-weight:normal; font-size:28px; } h1{ color: #D1232B; font-weight:normal; font-size:21px; margin-bottom:-5px } h2{ color: #646464; font-weight:bold; font-size:18px; } h3{ color: #000000; font-weight:BOLD; font-size:16px; text-decoration:underline; } h4{ color: #646464; font-weight:BOLD; font-size:15px; text-decoration:; } h5{ color: #000000; font-weight:BOLD; font-size:13px; text-decoration:; } h6{ color: #000000; font-weight:BOLD; font-size:14px; text-decoration:; } hr{ border-top-width: 1px; border-top-style: solid; border-top-color: #cccccc; } ul { list-style: disc outside none; margin-left: 0; } li { padding-left: 1em; } --> 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_changecolumns: 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