SET @base_seq = (SELECT CAST(variable_value AS UNSIGNED) FROM performance_schema.global_status WHERE variable_name = 'Lizard_commit_gcn');
SHOW VARIABLES LIKE "gcn_write_event";
Variable_name	Value
gcn_write_event	ON
SHOW STATUS LIKE "%gcn%";
Variable_name	Value
Lizard_commit_gcn	1024
Lizard_snapshot_gcn	1024
Lizard_purged_gcn	1024
Lizard_buffer_pool_txn_lookup_gcn_read_sees	0
create database mydb;
use mydb;
create table t1 (a int, b int, primary key(a));
set innodb_snapshot_seq = @base_seq +10000;
select * from t1;
a	b
insert into t1 values (0,0);
xa begin 'x1';
insert into t1 values (1,1);
xa end 'x1';
xa commit 'x1' one phase;
xa begin 'x2';
insert into t1 values (2,2);
xa end 'x2';
xa prepare 'x2';
set innodb_commit_seq  = 10001;
xa commit 'x2';
alter table t1 engine='innodb';
show binlog events in 'binlog.000001' from 1857 limit 6;
Log_name	Pos	Event_type	Server_id	End_log_pos	Info
binlog.000001	1857	Gcn	1	32	#
binlog.000001	1889	Anonymous_Gtid	1	111	#
binlog.000001	1968	Query	1	186	#
binlog.000001	2043	Table_map	1	235	#
binlog.000001	2092	Write_rows	1	279	#
binlog.000001	2136	Xid	1	310	#
show binlog events in 'binlog.000001' from 3453 limit 3;
Log_name	Pos	Event_type	Server_id	End_log_pos	Info
binlog.000001	3453	Gcn	1	32	#
binlog.000001	3485	Anonymous_Gtid	1	109	#
binlog.000001	3562	Query	1	227	#
delete from t1;
flush logs;
# restart: --gcn_write_event=false
SET @base_seq = (SELECT CAST(variable_value AS UNSIGNED) FROM performance_schema.global_status WHERE variable_name = 'Lizard_commit_gcn');
set innodb_snapshot_seq = @base_seq +20000;
select * from t1;
a	b
insert into t1 values (20,20);
xa begin 'x1';
insert into t1 values (21,21);
xa end 'x1';
xa commit 'x1' one phase;
xa begin 'x2';
insert into t1 values (22,22);
xa end 'x2';
xa prepare 'x2';
set innodb_commit_seq  = @base_seq +20001;
xa commit 'x2';
alter table t1 engine='innodb';
show binlog events in 'binlog.000002' from 393 limit 5;
Log_name	Pos	Event_type	Server_id	End_log_pos	Info
binlog.000002	393	Anonymous_Gtid	1	79	#
binlog.000002	472	Query	1	154	#
binlog.000002	547	Table_map	1	203	#
binlog.000002	596	Write_rows	1	247	#
binlog.000002	640	Xid	1	278	#
show binlog events in 'binlog.000002' from 1861 limit 2;
Log_name	Pos	Event_type	Server_id	End_log_pos	Info
binlog.000002	1861	Anonymous_Gtid	1	77	#
binlog.000002	1938	Query	1	195	#
# restart:
drop database mydb;