Rejects blocking client sessions while node acts as a donor to a blocking SST operation.
In a State Snapshot Transfer (SST), a donor node copies its local database and sends it to a joiner node, allowing the joiner to quickly bring itself into sync with the cluster. The specific SST method is set using the wsrep_sst_method system variable. Certain SST methods are blocking, meaning that during the operation the donor node blocks write operations from modifying the database.
This system variable configures how the node handles client connections while operating as a donor. When enabled, if a client or connector attempts to establish a blocking connection to the node while it performing a State Snapshot Transfer as a donor, the node rejects the connection.
BOOLEAN (OFF, ON)
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_sst_donor_rejects_queries page in the SkySQL Documentation.