mysql數據庫開機報錯： 
InnoDB: The log sequence number in ibdata files does not match 
InnoDB: the log sequence number in the ib_logfiles! 
100224 12:24:20 InnoDB: Database was not shut down normally! 
InnoDB: Starting crash recovery. 
InnoDB: Reading tablespace information from the .ibd files... 
InnoDB: Restoring possible half-written data pages from the doublewrite 
InnoDB: buffer... 
InnoDB: Transaction 0 4497755 was in the XA prepared state. 
InnoDB: Transaction 0 4468551 was in the XA prepared state. 
InnoDB: Transaction 0 4468140 was in the XA prepared state. 
InnoDB: 3 transaction(s) which must be rolled back or cleaned up 
InnoDB: in total 0 row operations to undo 
InnoDB: Trx id counter is 0 5312768 
InnoDB: Starting in background the rollback of uncommitted transactions 
100224 12:24:20 InnoDB: Rollback of non-prepared transactions completed 
100224 12:24:20 InnoDB: Started; log sequence number 0 3805002509 
100224 12:24:20 InnoDB: Starting recovery for XA transactions... 
100224 12:24:20 InnoDB: Transaction 0 4497755 in prepared state after recovery 
100224 12:24:20 InnoDB: Transaction contains changes to 8 rows 
100224 12:24:20 InnoDB: Transaction 0 4468551 in prepared state after recovery 
100224 12:24:20 InnoDB: Transaction contains changes to 1 rows 
100224 12:24:20 InnoDB: Transaction 0 4468140 in prepared state after recovery 
100224 12:24:20 InnoDB: Transaction contains changes to 1 rows 
100224 12:24:20 InnoDB: 3 transactions in prepared state after recovery 
100224 12:24:20 [Note] Found 3 prepared transaction(s) in InnoDB 
100224 12:24:20 [Warning] Found 3 prepared XA transactions 
100224 12:24:20 [Note] Event Scheduler: Loaded 0 events 
100224 12:24:20 [Note] /opt/mysql/bin/mysqld: ready for connections. 
Version: '5.1.39' socket: '/tmp/mysql.sock' port: 3306 MySQL Community Server (GPL) 
意味著有三個XA的事務沒有提交或回滾。 
登錄到mysql 
mysql> xa recover; 
+----------+--------------+--------------+------------------------------------------------------------+ 
| formatID | gtrid_length | bqual_length | data | 
+----------+--------------+--------------+------------------------------------------------------------+ 
| 131075 | 30 | 28 | 1-7f000001:bae5:4b6928eb:f06397f000001:bae5:4b6928eb:f0650 | 
| 131075 | 30 | 28 | 1-7f000001:bae5:4b6928eb:fb5c37f000001:bae5:4b6928eb:fb5cd | 
| 131075 | 30 | 28 | 1-7f000001:bae5:4b6928eb:f03ea7f000001:bae5:4b6928eb:f0400 | 
+----------+--------------+--------------+------------------------------------------------------------+ 
數據表示信息如下： 
formatIDis the formatIDpart of the transaction xid 
gtrid_lengthis the length in bytes of the gtridpart of the xid 
bqual_lengthis the length in bytes of the bqualpart of the xid 
datais the concatenation of the gtridand bqualparts of the xid 
這是三個XA事務的信息，準備直接回滾。 
mysql> xa rollback '1-7f000001:bae5:4b6928eb:fb5c3','7f000001:bae5:4b6928eb:fb5cd',131075; 
Query OK, 0 rows affected (0.41 sec) 
再啟動就正常了。 

MySQL XA 
I.5. 對XA事務的限制 
XA事務支持限于InnoDB存儲引擎。 
MySQL XA實施是針對外部XA的，其中，MySQL服務器作為資源管理器，而客戶端程序作為事務管理器。未實施“內部XA”。這樣，就允許MySQL服務器內的單獨存儲引擎作為RM（資源管理器），而服務器本身作為TM（事務管理器）。處理包含1個以上存儲引擎的XA事務時，需要內部XA。內部XA的實施是不完整的，這是因為，它要求存儲引擎在表處理程序層面上支持兩階段提交，目前僅對InnoDB實現了該特性。 
對于XA START，不支持JOIN和RESUME子句。 

對于XA END，不支持SUSPEND [FOR MIGRATE]子句。 
在全局事務內，對于每個XA事務，xid值的bqual部分應是不同的，該要求是對當前MySQL XA實施的限制。它不是XA規范的組成部分。 

如果XA事務達到PREPARED狀態而且MySQL服務器宕機，當服務器重啟后，能夠繼續處理事務。就像原本應當的那樣。但是，如果客戶端連接中止而服務器繼續運行，服務器將回滾任何未完成的XA事務，即使該事務已達到PREPARED狀態也同樣。它應能提交或回滾PREPARED XA事務，但在不更改二進制日志機制的情況下不能這樣。