Increment subtransactions number when we detect an EXCEPTION

lib/gitlab/database/transaction/observer.rb

@@ -21,7 +21,7 @@ module Gitlab
             context.set_start_time
             context.set_depth(0)
             context.track_sql(event.payload[:sql])
-          elsif cmd.start_with?('SAVEPOINT ')
+          elsif cmd.start_with?('SAVEPOINT', 'EXCEPTION')
             context.set_depth(manager.open_transactions)
             context.increment_savepoints
           elsif cmd.start_with?('ROLLBACK TO SAVEPOINT')