MySQL has locking capabilities, for example table and row level locking, and such locks are needed to control data integrity in multi-user concurrency. Deadlocks—where two or more transactions are waiting for one another to give up locks before the transactions can proceed successfully—are an unwanted situation. It is a classic problem for all databases including […]

Galera cluster has known limitations, one of them is that it uses cluster-wide optimistic locking. This may cause some transactions to rollback. With an increasing number of writeable masters, the transaction rollback rate may increase, especially if there is write contention on the same dataset. It is of course possible to retry the transaction and perhaps it will COMMIT in the retries, but this will add to the transaction latency. However, some designs are deadlock prone, e.g sequence tables. In this blog we present how you can minimize the risk for deadlocks due to the design of Galera.