select count_star into @init_count from performance_schema.events_waits_summary_global_by_event_name WHERE event_name LIKE '%wait%io%file%innodb%innodb_temp_file%';
connect  ddl, localhost, root,,;
update performance_schema.setup_instruments set enabled='yes';
update performance_schema.setup_consumers set enabled='yes';
CREATE TABLE t1 (a serial, b varchar(255)) ENGINE=InnoDB;
BEGIN;
COMMIT;
SET DEBUG_SYNC = 'row_log_apply_before SIGNAL go WAIT_FOR gone';
ALTER TABLE t1 ADD INDEX(b), ALGORITHM=INPLACE;
connection default;
SET DEBUG_SYNC = 'now WAIT_FOR go';
select count_star into @final_count from performance_schema.events_waits_summary_global_by_event_name WHERE event_name LIKE '%wait%io%file%innodb%innodb_temp_file%';
SELECT @final_count - @init_count;
@final_count - @init_count
10
SET DEBUG_SYNC = 'now SIGNAL gone';
connection ddl;
disconnect ddl;
connection default;
SET DEBUG_SYNC = 'RESET';
DROP TABLE t1;