CREATE TABLE t1 (f1 INTEGER) Engine=InnoDB;
SET GLOBAL wsrep_slave_threads = 10;
SET GLOBAL wsrep_slave_threads = 1;
INSERT INTO t1 VALUES (1);
SET GLOBAL wsrep_slave_threads = 10;
SELECT COUNT(*) = 11 FROM INFORMATION_SCHEMA.PROCESSLIST WHERE USER = 'system user';
COUNT(*) = 11
1
SET GLOBAL wsrep_slave_threads = 20;
SELECT COUNT(*) = 21 FROM INFORMATION_SCHEMA.PROCESSLIST WHERE USER = 'system user';
COUNT(*) = 21
1
SET GLOBAL wsrep_slave_threads = 1;
INSERT INTO t1 VALUES (1);
INSERT INTO t1 VALUES (2);
INSERT INTO t1 VALUES (3);
INSERT INTO t1 VALUES (4);
INSERT INTO t1 VALUES (5);
INSERT INTO t1 VALUES (6);
INSERT INTO t1 VALUES (7);
INSERT INTO t1 VALUES (8);
INSERT INTO t1 VALUES (9);
SET GLOBAL wsrep_slave_threads = 10;
SET GLOBAL wsrep_slave_threads = 0;
Warnings:
Warning	1292	Truncated incorrect wsrep_slave_threads value: '0'
INSERT INTO t1 VALUES (10);
INSERT INTO t1 VALUES (11);
INSERT INTO t1 VALUES (12);
INSERT INTO t1 VALUES (13);
INSERT INTO t1 VALUES (14);
INSERT INTO t1 VALUES (15);
INSERT INTO t1 VALUES (16);
INSERT INTO t1 VALUES (17);
INSERT INTO t1 VALUES (18);
INSERT INTO t1 VALUES (19);
INSERT INTO t1 VALUES (20);
SELECT COUNT(*) = 2 FROM INFORMATION_SCHEMA.PROCESSLIST WHERE USER = 'system user';
COUNT(*) = 2
1
SET GLOBAL wsrep_slave_threads = 1;
DROP TABLE t1;