set @@session.time_zone='+00:00'; select ifnull(max(trx_id), 0) into @start_trx_id from information_schema.innodb_vtq; create procedure if not exists verify_vtq() begin set @i= 0; select @i:= @i + 1 as No, trx_id > 0 as A, commit_id >= trx_id as B, begin_ts > '1-1-1 0:0:0' as C, commit_ts > begin_ts as D from information_schema.innodb_vtq where trx_id > @start_trx_id; select ifnull(max(trx_id), 0) into @start_trx_id from information_schema.innodb_vtq; end~~ create table t1( id int auto_increment primary key) with system versioning engine innodb; set transaction isolation level read uncommitted; insert into t1 values (); select iso_level = 'RU' from information_schema.innodb_vtq limit 1; iso_level = 'RU' 1 set transaction isolation level read committed; insert into t1 values (); select iso_level = 'RC' from information_schema.innodb_vtq limit 1; iso_level = 'RC' 1 set transaction isolation level serializable; insert into t1 values (); select iso_level = 'S' from information_schema.innodb_vtq limit 1; iso_level = 'S' 1 set transaction isolation level repeatable read; insert into t1 values (); select iso_level = 'RR' from information_schema.innodb_vtq limit 1; iso_level = 'RR' 1 set @ts0= now(6); insert into t1 values (); select sys_trx_start from t1 where id = last_insert_id() into @tx0; select trx_id = @tx0 from information_schema.innodb_vtq limit 1; trx_id = @tx0 1 set @ts1= now(6); insert into t1 values (); select sys_trx_start from t1 where id = last_insert_id() into @tx1; select trx_id = @tx1 from information_schema.innodb_vtq limit 1; trx_id = @tx1 1 set @ts2= now(6); insert into t1 values (); select sys_trx_start from t1 where id = last_insert_id() into @tx2; select trx_id = @tx2 from information_schema.innodb_vtq limit 1; trx_id = @tx2 1 set @ts3= now(6); select vtq_trx_id(@ts0) < @tx0 as A, vtq_trx_id(@ts0, true) = @tx0 as B, vtq_trx_id(@ts1) = @tx0 as C, vtq_trx_id(@ts1, true) = @tx1 as D, vtq_trx_id(@ts2) = @tx1 as E, vtq_trx_id(@ts2, true) = @tx2 as F, vtq_trx_id(@ts3) = @tx2 as G, vtq_trx_id(@ts3, true) is null as H; A B C D E F G H 1 1 1 1 1 1 1 1 select vtq_commit_id(@ts0) < @tx0 as A, vtq_commit_id(@ts0, true) = vtq_commit_id(null, @tx0) as B, vtq_commit_id(@ts1) = vtq_commit_id(null, @tx0) as C, vtq_commit_id(@ts1, true) = vtq_commit_id(null, @tx1) as D, vtq_commit_id(@ts2) = vtq_commit_id(null, @tx1) as E, vtq_commit_id(@ts2, true) = vtq_commit_id(null, @tx2) as F, vtq_commit_id(@ts3) = vtq_commit_id(null, @tx2) as G, vtq_commit_id(@ts3, true) is null as H; A B C D E F G H 1 1 1 1 1 1 1 1 select vtq_trx_sees(@tx1, @tx0) as A, not vtq_trx_sees(@tx0, @tx1) as B, vtq_trx_sees_eq(@tx1, @tx1) as C, not vtq_trx_sees(@tx1, @tx1) as D, vtq_trx_sees(@tx2, 0) as E, vtq_trx_sees(0, @tx2) is null as F, vtq_trx_sees(-1, @tx2) as H; A B C D E F H 1 1 1 1 1 1 1 drop table t1; call verify_vtq; No A B C D 1 1 1 1 1 2 1 1 1 1 3 1 1 1 1 4 1 1 1 1 5 1 1 1 1 6 1 1 1 1 7 1 1 1 1 drop procedure verify_vtq;