Tag - flow control

Monitoring MySQL flow control in Percona XtraDB Cluster 5.6

Monitoring flow control in a Galera cluster is very important. If you do not, you will not understand why writes may sometimes be stalled. Percona XtraDB Cluster 5.6 provides 2 status variables for such monitoring: wsrep_flow_control_paused and wsrep_flow_control_paused_ns. Which one should you use?
What is flow control?
Flow control does not exist with regular MySQL replication, but […]

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Taking backups on Percona XtraDB Cluster (without stalls!)

I occasionally see customers who are taking backups from their PXC clusters that complain that the cluster “stalls” during the backup.  As I wrote about in a previous blog post, often these stalls are really just Flow Control.  But why would a backup cause Flow control?
Most backups I know of (even Percona XtraBackup) take […]

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MySQL Webinar: Percona XtraDB Cluster Operations, June 26

Percona XtraDB Cluster (PXC) was released over a year ago and since then there has been tremendous interest and adoption.  There’s plenty of talks that explain the fundamentals of PXC, but we’re starting to reach a threshold where it’s easier to find folks with PXC in production and such the need for more advanced […]

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Galera Flow Control in Percona XtraDB Cluster for MySQL

Last week at Percona Live, I delivered a six-hour tutorial about Percona XtraDB Cluster (PXC) for MySQL.  I actually had more material than I covered (by design), but one thing I regret we didn’t cover was Flow control.  So, I thought I’d write a post covering flow control because it is important to understand.
What […]

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