Github user jburwell commented on the issue: https://github.com/apache/cloudstack/pull/1762 @yvsubhash according to the (MySQL deadlock documenation)[http://dev.mysql.com/doc/refman/5.7/en/innodb-deadlocks.html], a `MYSQL_DEADLOCK_ERROR_CODE` error indicates the enclosing transaction has been rolled back. The proper handling for this error is to re-execute all statements executed in the aborted transaction. From a best practices perspective, all base data should be re-retrieved and changed to ensure logical consistency with changes made by the transaction that won deadlock resolution. As I understand this patch, only the most recently executed DML is retried. Therefore, any previously executed changes will be discarded and the DML will be re-executed either in a new transaction or in auto-commit (I didn't look up how the client handles the transaction context in this scenario). If my understanding is correct, this patch could lead to issues ranging from unexpected foreign key integrity errors to data corruption. Rather attempting to implement a generic retry, I think the best approach to addressing deadlocks is to treat them bugs. This patch could be modified to provide detailed logging information about the conditions under which a deadlock occurs providing the information necessary to refactor the system to avoid lock contention.
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