In this blog post, we’ll discuss trackable flow control in Percona XtraDB Cluster.
Introduction
Percona XtraDB Cluster has a self-regulating mechanism called Flow Control. This mechanism helps to avoid a situation wherein the weakest/slowest member of the cluster falls significantly behind other members of the cluster.
When a member of a cluster is slow at applying write-sets (while simultaneously continuing to receive write-sets from the cluster group channel), then the incoming/receive queue grows in size. If this queue crosses a set threshold (gcs.fc_limit), the node emits a FLOW_CONTROL message asking other members to slow down or halt processing.
While …
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