8 background threads |\n +-------------------------------+\n 1 row in set (0.00 sec)\n ' SQL SECURITY INVOKER NOT DETERMINISTIC MODIFIES SQL DATA BEGIN UPDATE performance_schema.threads SET instrumented = 'YES' WHERE type = 'BACKGROUND';  SELECT CONCAT('Enabled ', @rows := ROW_COUNT(), ' background thread', IF(@rows != 1, 's', '')) AS summary; END;