BlockedTransaction CloudWatch alarm always in INSUFFICIENT DATA state.

Blockedtransactions is a cloudwatch metrics applicable for Aurora MySQL only. It gives average number of transactions in the database that are blocked per second this metric is based on innodb metric It is # of transactions currently waiting on row locks it is evaluated using

SELECT name, subsystem, status, count FROM INFORMATION_SCHEMA.INNODB_METRICS where NAME like 'LOCK_ROW_LOCK_CURRENT_WAITS';

+-----------------------------+-----------+---------+-------+
| name | subsystem | status | count |
+-----------------------------+-----------+---------+-------+
| lock_row_lock_current_waits | lock | enabled | 0 |
+-----------------------------+-----------+---------+-------+
1 row in set (0.08 sec)