Impact of large write transactions on cluster performance

1

Hello Percona Community,

We would like to find guidance on managing large write transactions (MBs/thousands of rows) that are impacting Percona XtraDB Cluster performance. Could you briefly explain the mechanism inside Percona XtraDB cluster that causes these large writes to trigger Flow Control (FC) and throttle the cluster?

Which status variables should we check to confirm FC activity and the replication queue size? Is it - wsrep_flow_control_paused, wsrep_local_recv_queue_avg? Finally, what are the most important settings or general practices we can change to stop large transactions from slowing down the cluster?

Thank you!

2

Have a look at streaming replication. Set wsrep_trx_fragment_unit to bytes, rows, or statements and then tune wsrep_trx_fragment_size to match whatever unit you picked. Also check wsrep_applier_threads and set this to 1/2 the number of CPUs.

1 Like
3

Hey QLCaesar!

We have some blogposts that gives more details about what flow control does and how to monitor. For example:

There are many other related posts in our blog that you might find interesting as well

Regards

1 Like