IT notes

galera SOS

Check status of cluster: https://nbari.com/post/galera/ Find process list not sleeping: SELECT user, time, state, info FROM information_schema.processlist WHERE command != 'Sleep' AND time >= 2 ORDER BY time DESC, id; Doing a heavy DDL (ALTER): SELECT * FROM information_schema.processlist WHERE command != 'Sleep' AND info LIKE 'alter%' AND time >= 2 ORDER BY time DESC, id LIMIT 1; DDL stands for data definition language. It is a set of SQL statements that work on the database as a whole, rather than an individual table or row.

Galera

To periodically check status of the cluster, create a script (/tmp/xx): #!/bin/sh mysql -e \ "SHOW GLOBAL STATUS WHERE Variable_name IN ( 'wsrep_cert_deps_distance', 'wsrep_cluster_size', 'wsrep_cluster_status', 'wsrep_connected', 'wsrep_evs_delayed', 'wsrep_flow_control_paused', 'wsrep_flow_control_paused_ns', 'wsrep_flow_control_recv', 'wsrep_flow_control_sent', 'wsrep_local_index', 'wsrep_local_state', 'wsrep_local_state_comment', 'wsrep_ready', 'wsrep_replicated', 'wsrep_replicated_bytes');" if credentials are in a custom path: mysql --defaults-file=/path/to/.my.cnf -s -e And run it with: watch sh /tmp/xx If single node alive (ERROR 1047 WSREP has not yet prepared node for application use):