mvcc_mysql_exmaple

mvcc_mysql

---- create table
drop table if exists t0;

create table t0 (
  pk int primary key, 
  col0 int, 
  col1 int
); 

insert into t0 values (0,1,2), (1,2,3);  

---- T1
drop table if exists t0;

create table t0 (
  pk int primary key, 
  col0 int, 
  col1 int
); 

insert into t0 values (0,1,2), (1,2,3);

---- T1
start transaction;
select pk from t0;
insert into t0 value (2,3,5);
commit;

---- T2
start transaction;
select pk from t0;
insert into t0 value (2,3,5);
select pk from t0;
update t0 set col0 = 1 where pk > 0;
select pk from t0; ---- different?
commit;

order.txt

-- T1 --			-- T2 --

start transaction;		
				start transaction; 
select pk from t0;		
insert into t0 value (2,3,5);		
				select pk from t0; ---- first read
commit;
				select pk from t0; ---- second read (same)
				update t0 set col0 = 1 where pk > 0; ---- also updated (2,3,5) to (2,1,5)
				select pk from t0; ---- third read (different!??)
				commit;