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innodb_flush_log_at_trx_commit
0: 每隔1s，系统后台线程刷log buffer,也就是把redo日志刷盘，这里会调用fsync，所以可能丢失最后1s的事务。
1: 每次commit时，刷redo日志，确定fsync刷盘
2: 每次提交时，刷redo日志到文件系统，不调用fsync刷盘，5.6.6之前是每隔1s刷盘，之后的版本是通过参数innodb_flush_log_at_timeout设置，默认也是1s。所以也可能丢最后一秒的事务。如果有掉电保护组件的话，可以开启。
sync_binlog
表示每多少个sync事件触发一次真正的binlog fsync刷盘，默认是1，表示每次commit时binlog都会fsync。
这个两阶段提交不是分布式事务的两阶段提交，而是在开启binlog之后，redo与binlog的两阶段提交。 两阶段提交，首先redo log prepare，然后写binlog，最后redo log commit.
2015-07-29 17:03:18 21957 [Note] Starting crash recovery...
2015-07-29 17:03:18 7ffff7fe4780 InnoDB: Starting recovery for XA transactions...
2015-07-29 17:03:18 7ffff7fe4780 InnoDB: Transaction 35077 in prepared state after recovery
2015-07-29 17:03:18 7ffff7fe4780 InnoDB: Transaction contains changes to 1 rows
2015-07-29 17:03:18 7ffff7fe4780 InnoDB: 1 transactions in prepared state after recovery
2015-07-29 17:03:18 21957 [Note] Found 1 prepared transaction(s) in InnoDB
2015-07-29 17:03:18 21957 [Note] rollback xid ‘MySQLXid\1\0\0\0\0\0\0\0\6\0\0\0\0\0\0\0‘2015-07-29 17:06:23 7ffff7fe4780 InnoDB: Starting recovery for XA transactions...
2015-07-29 17:06:23 7ffff7fe4780 InnoDB: Transaction 35590 in prepared state after recovery
2015-07-29 17:06:23 7ffff7fe4780 InnoDB: Transaction contains changes to 1 rows
2015-07-29 17:06:23 7ffff7fe4780 InnoDB: 1 transactions in prepared state after recovery
2015-07-29 17:06:23 22040 [Note] Found 1 prepared transaction(s) in InnoDB
2015-07-29 17:06:23 22040 [Note] commit xid ‘MySQLXid\1\0\0\0\0\0\0\0\6\0\0\0\0\0\0\0‘
2015-07-29 17:06:23 22040 [Note] Crash recovery finished.innodb_flush_log_at_trx_commit 为0， sync_binlog=1，此时redo log没有刷盘，binlog刷盘了，recover的时候不会根据binlog恢复。
所以强烈建议这两个参数都设置成1.
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原文地址：http://www.cnblogs.com/conanwang/p/5935630.html
