MySQL如何查询当前最新事务ID

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150303 17:16:11 INNODB MONITOR OUTPUT
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Per second averages calculated from the last 15 seconds
...
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TRANSACTIONS
Trx id counter 3359877657 -- 当前最大事务 ID
Purge done for trx"s n:o <3359877468 undo n:o <0 state: running
History list length 324
LIST OF TRANSACTIONS FOR EACH SESSION:
---TRANSACTION 0, not started -- 该会话中执行 SHOW ENGINE INNODB STATUS，不会产生事务，所以事务 ID 为 0
MySQL thread id 4692367, OS thread handle 0x51103940, query id 677284426 xx.173ops.com 10.x.x.x yejr init
SHOW /*!50000 ENGINE*/ INNODB STATUS
---TRANSACTION 3359877640, not started --非活跃事务，还未开始
mysql tables in use 1, locked 0
MySQL thread id 4678384, OS thread handle 0x41a57940, query id 677284427 xx.173ops.com 10.x.x.x yejr System lock
select polinfo0_.Fid as Fid39_0_, ...

---TRANSACTION 3359877652, not started
MySQL thread id 4678383, OS thread handle 0x50866940, query id 677284420 xx.173ops.com 10.x.x.x yejr cleaning up

---TRANSACTION 3359877635, ACTIVE 1358 sec, thread declared inside InnoDB 5000 --活跃长事务，运行了 1358 秒还未结束，要引起注意，可能会导致大量锁等待发生
mysql tables in use 1, locked 1
1 lock struct(s), heap size 376, 0 row lock(s), undo log entries 1
MySQL thread id 3120717, OS thread handle 0x529b4940, query id 677284351 xx.173ops.com 10.x.x.x yejr query end
insert into t_live_room ...

mysql> SELECT * FROM INFORMATION_SCHEMA.INNODB_TRXG
*************************** 1. row ***************************
 trx_id: 17778 -- 当前事务 ID
 trx_state: LOCK WAIT -- 处于锁等待状态，也就是等待其他会话释放锁资源
 trx_started: 2015-03-04 10:40:26
 trx_requested_lock_id: 17778:82:3:6 -- 欲请求的锁
 trx_wait_started: 2015-03-04 10:40:26
 trx_weight: 2 -- 大意是该锁影响了 2 行记录
 trx_mysql_thread_id: 657 -- processlist 中的线程 ID
 trx_query: update trx_fee set fee=rand()*1000 where id= 4
 trx_operation_state: starting index read
 trx_tables_in_use: 1
 trx_tables_locked: 1
 trx_lock_structs: 2
 trx_lock_memory_bytes: 360
 trx_rows_locked: 1
 trx_rows_modified: 0
 trx_concurrency_tickets: 0
 trx_isolation_level: REPEATABLE READ
 trx_unique_checks: 1
 trx_foreign_key_checks: 1
 trx_last_foreign_key_error: NULL
 trx_adaptive_hash_latched: 0
 trx_adaptive_hash_timeout: 10000
 trx_is_read_only: 0
 trx_autocommit_non_locking: 0
 *************************** 2. row ***************************
 trx_id: 17773
 trx_state: RUNNING
 trx_started: 2015-03-04 10:40:23
 trx_requested_lock_id: NULL
 trx_wait_started: NULL
 trx_weight: 10
 trx_mysql_thread_id: 656
 trx_query: NULL
 trx_operation_state: NULL
 trx_tables_in_use: 0
 trx_tables_locked: 0
 trx_lock_structs: 2
 trx_lock_memory_bytes: 360
 trx_rows_locked: 9
 trx_rows_modified: 8
 trx_concurrency_tickets: 0
 trx_isolation_level: REPEATABLE READ
 trx_unique_checks: 1
 trx_foreign_key_checks: 1
 trx_last_foreign_key_error: NULL
 trx_adaptive_hash_latched: 0
 trx_adaptive_hash_timeout: 10000
 trx_is_read_only: 0
 trx_autocommit_non_locking: 0

mysql> select * from information_schema.INNODB_LOCKSG
*************************** 1. row ***************************
lock_id: 17778:82:3:6 --当前锁 ID
lock_trx_id: 17778 --该锁对应的事务 ID
lock_mode: X -- 锁类型，排它锁 X
lock_type: RECORD --锁范围，记录锁：record lock，其他锁范围：间隙锁：gap lock，或者 next-key lock（记录锁+间隙锁）
lock_table: `test`.`trx_fee`
lock_index: PRIMARY --加载在哪个索引上的锁
lock_space: 82
lock_page: 3
lock_rec: 6
lock_data: 4
*************************** 2. row ***************************
lock_id: 17773:82:3:6
lock_trx_id: 17773
lock_mode: X
lock_type: RECORD
lock_table: `test`.`trx_fee`
lock_index: PRIMARY
lock_space: 82
lock_page: 3
lock_rec: 6
lock_data: 4

mysql> select * from information_schema.INNODB_LOCK_WAITSG
*************************** 1. row ***************************
requesting_trx_id: 17778 --请求锁的事务 ID（等待方）
requested_lock_id: 17778:82:3:6 -- 请求锁 ID
blocking_trx_id: 17773 -- 阻塞该锁的事务 ID（当前持有方，待释放）
blocking_lock_id: 17773:82:3:6 -- 持有的锁 ID

mysqladmin ext | grep Innodb_max_trx_id
或者
mysql> show global status like "Innodb_max_trx_id";

begin;update trx set un=rand() where id=round(rand()*10)+1;select * from information_schema.INNODB_TRX; commit;select sleep(0.01);begin;update trx set un=rand() where id=round(rand()*10)+1;select * from information_schema.INNODB_TRX;commit;