Galera Cluster Thread States
This article documents thread states that are specific to MariaDB Enterprise Cluster and appear in the SHOW PROCESSLIST when nodes are performing cluster-specific operations. These states enable monitoring of session status within clustered environments.
The following table lists the thread states present in Galera Cluster and their descriptions:
waiting to execute in isolation
The thread is waiting to execute a transaction in isolation mode.
waiting for TOI DDL
The thread is waiting for a Total Order Isolation Data Definition Language (DDL) operation to complete.
waiting for flow control
The thread is paused due to Galera flow control, which regulates replication throughput.
waiting for certification
The transaction is waiting for Galera transaction certification before it can be applied to avoid conflict with other transactions.
These states contribute in the identification of synchronization delays and performance bottlenecks in a Galera Cluster framework.
These states were introduced in MariaDB Enterprise Server 11.4 and are also available in MariaDB Community Server 11.0.3 and later.
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