Bitmask to configure synchronization waits for causality checks on the cluster.
Cluster Nodes can perform causality checks in response to certain types of SQL statements.
When an SQL statement triggers a causality check, the node waits for synchronization before executing the query. During synchronization, the node applies any outstanding write-sets from the cluster up to the point where it received the statement. It then executes the statement and returns the result-set.
Enabling causality checks ensures that certain types of queries always execute against the most up to date database state, at the expense of query performance.
This system variable specifies the types of statements that trigger causality checks:
Disables causality checks.
Performs causality checks on show operations, such as SHOW TABLES statements.
Additional information on this topic may be found in the MariaDB Public Knowledge Base.
Information specific to MariaDB SkySQL can be found on the wsrep_sync_wait page in the SkySQL Documentation.