The code provided processes allCaserecords in a single transaction. Since it attempts to process over 10,000 records, it exceeds the Salesforce governor limit of 50,000 DML rows per transaction, causing the transaction to fail.
Governor Limits on DML Rows (C):Salesforce enforces a governor limit of 50,000 rows for DML operations per transaction. In this case, if theSELECTquery retrieves over 50,000 records, theDatabase.updatecall will hit this limit and throw aSystem.LimitException.
Reference:Apex Governor Limits
Why the Try-Catch Block Fails to Handle Limits (B & D):Governor limit exceptions (System.
LimitException) cannot be caught by try-catch blocks. Therefore, the exception cannot be handled, and the transaction will fail.