１结合Ｍｙｃａｔ日志，分析select * from travelrecord order by id limit100000,100 的执行过程，解释下当limit M,N中的M非常大的情况下，为什么查询结果会变慢很多
1.1mycat控制命令台显示，explain出来走了所有的节点
mysql>explain select * from travelrecord order by id limit 100000,100 ; +-----------+--------------------------------------------------------+ |DATA_NODE | SQL | +-----------+--------------------------------------------------------+ |dn1 | SELECT * FROM travelrecordORDER BY id LIMIT 0, 100100 | |dn2 | SELECT * FROM travelrecordORDER BY id LIMIT 0, 100100 | |dn3 | SELECT * FROM travelrecordORDER BY id LIMIT 0, 100100 | +-----------+--------------------------------------------------------+ 3rows in set (0.01 sec) mysql>1.2看后台mycat.log日志：
02/1417:52:30.103 DEBUG [$_NIOREACTOR-0-RW](ServerQueryHandler.java:56) -ServerConnection [id=3, schema=TESTDB,host=127.0.0.1, user=test,txIsolation=3, autocommit=true, schema=TESTDB]explainselect * from travelrecord order by id limit 1000000,100 02/1417:52:30.103 DEBUG [$_NIOREACTOR-0-RW](EnchachePool.java:76) -SQLRouteCache miss cache ,key:TESTDB select * from travelrecord order by id limit1000000,100 02/1417:52:30.105 DEBUG [$_NIOREACTOR-0-RW] (EnchachePool.java:59)-SQLRouteCache add cache ,key:TESTDB select * from travelrecord order by idlimit 1000000,100 value:select * from travelrecord order by id limit1000000,100, route={ 1 -> dn1{SELECT * FROMtravelrecord ORDERBY id LIMIT0, 1000100} 2 -> dn2{SELECT * FROMtravelrecord ORDERBY id LIMIT0, 1000100} 3 -> dn3{SELECT * FROMtravelrecord ORDERBY id LIMIT0, 1000100} } 02/1417:52:33.880 DEBUG [$_NIOREACTOR-0-RW](ServerQueryHandler.java:56) -ServerConnection [id=3, schema=TESTDB,host=127.0.0.1, user=test,txIsolation=3, autocommit=true, schema=TESTDB]select* from travelrecord order by id limit 1000000,100 02/1417:52:33.881 DEBUG [$_NIOREACTOR-0-RW](EnchachePool.java:76) -SQLRouteCache miss cache ,key:TESTDBselect * from travelrecord order by id limit1000000,100 02/1417:52:33.882 DEBUG [$_NIOREACTOR-0-RW](EnchachePool.java:59) -SQLRouteCache add cache ,key:TESTDBselect * fromtravelrecord order by id limit 1000000,100 value:select * from travelrecordorder by id limit 1000000,100, route={ 1 -> dn1{SELECT * FROMtravelrecord ORDERBY id LIMIT0, 1000100} 2 -> dn2{SELECT * FROMtravelrecord ORDERBY id LIMIT0, 1000100} 3 -> dn3{SELECT * FROMtravelrecord ORDERBY id LIMIT0, 1000100} } 02/1417:52:33.882 DEBUG [$_NIOREACTOR-0-RW](NonBlockingSession.java:113) -ServerConnection [id=3, schema=TESTDB,host=127.0.0.1, user=test,txIsolation=3, autocommit=true, schema=TESTDB]select* from travelrecord order by id limit 1000000,100, route={ 1 -> dn1{SELECT * FROMtravelrecord ORDERBY id 02/1417:52:33.882 DEBUG [$_NIOREACTOR-0-RW](NonBlockingSession.java:113) -ServerConnection [id=3, schema=TESTDB,host=127.0.0.1, user=test,txIsolation=3, autocommit=true, schema=TESTDB]select* from travelrecord order by id limit 1000000,100, route={ 1 -> dn1{SELECT * FROMtravelrecord ORDERBY id LIMIT0, 1000100} 2 -> dn2{SELECT * FROMtravelrecord ORDERBY id LIMIT0, 1000100} 3 -> dn3{SELECT * FROMtravelrecord ORDERBY id LIMIT0, 1000100} }rrs 02/1417:52:33.882 DEBUG [$_NIOREACTOR-0-RW](MultiNodeQueryHandler.java:82) -execute mutinode query select * from travelrecordorder by id limit 1000000,100 02/1417:52:33.882 DEBUG [$_NIOREACTOR-0-RW](MultiNodeQueryHandler.java:97) -has data merge logic 02/1417:52:33.882 DEBUG [$_NIOREACTOR-0-RW](PhysicalDBPool.java:452) -select read source hostM1 for dataHost:wgq_idc_mon_1_12 02/1417:52:33.883 DEBUG [$_NIOREACTOR-0-RW](PhysicalDBPool.java:452) -select read source hostM1 fordataHost:wgq_idc_mon_1_12 02/1417:52:33.883 DEBUG [$_NIOREACTOR-0-RW](PhysicalDBPool.java:452) -select read source hostM1 for dataHost:wgq_idc_mon_1_12 02/1417:52:33.883 DEBUG [$_NIOREACTOR-3-RW](MultiNodeQueryHandler.java:171) -received ok response ,executeResponse:falsefrom MySQLConnection [id=19, lastTime=1455443553868, user=root, schema=db1, oldshema=db1, borrowed=true, fromSlaveDB=false, threadId=220, charset=latin1,txIsolation=3, autocommit=true, attachment=dn1{SELECT * FROMtravelrecord ORDERBY id LIMIT0, 1000100},respHandler=org.opencloudb.mysql.nio.handler.MultiNodeQueryHandler@f35a686,host=110.254.11.111, port=3317, statusSync=org.opencloudb.mysql.nio.MySQLConnection$StatusSync@b47af37,writeQueue=0, modifiedSQLExecuted=false] 02/1417:52:33.884 DEBUG [$_NIOREACTOR-1-RW](MultiNodeQueryHandler.java:241) -on row end reseponse MySQLConnection [id=25,lastTime=1455443553868, user=root, schema=db3, old shema=db3, borrowed=true,fromSlaveDB=false, threadId=227, charset=latin1, txIsolation=3,autocommit=true, attachment=dn3{SELECT * FROMtravelrecord 02/1417:52:33.883 DEBUG [$_NIOREACTOR-3-RW](MultiNodeQueryHandler.java:171) -received ok response ,executeResponse:falsefrom MySQLConnection [id=19, lastTime=1455443553868, user=root, schema=db1, oldshema=db1, borrowed=true, fromSlaveDB=false, threadId=220, charset=latin1,txIsolation=3, autocommit=true, attachment=dn1{SELECT * FROMtravelrecord ORDERBY id LIMIT0, 1000100},respHandler=org.opencloudb.mysql.nio.handler.MultiNodeQueryHandler@f35a686,host=110.254.11.111, port=3317,statusSync=org.opencloudb.mysql.nio.MySQLConnection$StatusSync@b47af37,writeQueue=0, modifiedSQLExecuted=false] 02/1417:52:33.884 DEBUG [$_NIOREACTOR-1-RW](MultiNodeQueryHandler.java:241) -on row end reseponse MySQLConnection [id=25,lastTime=1455443553868, user=root, schema=db3, old shema=db3, borrowed=true,fromSlaveDB=false, threadId=227, charset=latin1, txIsolation=3,autocommit=true, attachment=dn3{SELECT * FROMtravelrecord ORDERBY id LIMIT0, 1000100},respHandler=org.opencloudb.mysql.nio.handler.MultiNodeQueryHandler@f35a686,host=110.254.11.111, port=3317, statusSync=null, writeQueue=0,modifiedSQLExecuted=false] 02/1417:52:33.884 DEBUG [$_NIOREACTOR-3-RW](DataMergeService.java:94) -field metadata inf:[ID=Colmeta [colIndex=0,colType=8], DAYS=Colmeta [colIndex=4, colType=3], TRAVELDATE=Colmeta[colIndex=2, colType=10], USER_ID=Colmeta [colIndex=1, colType=253],FEE=Colmeta [colIndex=3, colType=246]] 02/1417:52:33.884 DEBUG [$_NIOREACTOR-1-RW](NonBlockingSession.java:229) -release connection MySQLConnection [id=25,lastTime=1455443553868, user=root, schema=db3, old shema=db3, borrowed=true,fromSlaveDB=false, threadId=227, charset=latin1, txIsolation=3,autocommit=true, attachment=dn3{SELECT * FROMtravelrecord ORDERBY id LIMIT0, 1000100},respHandler=org.opencloudb.mysql.nio.handler.MultiNodeQueryHandler@f35a686,host=110.254.11.111, port=3317, statusSync=null, writeQueue=0,modifiedSQLExecuted=false] 02/1417:52:33.885 DEBUG [$_NIOREACTOR-1-RW](PhysicalDatasource.java:403) -release channel MySQLConnection [id=25,lastTime=1455443553868, user=root, schema=db3, old shema=db3, borrowed=true,fromSlaveDB=false, threadId=227, charset=latin1, txIsolation=3,autocommit=true, attachment=null, respHandler=null, host=110.254.11.111,port=3317, statusSync=null, writeQueue=0, modifiedSQLExecuted=false] 02/1417:52:33.886 DEBUG [$_NIOREACTOR-3-RW](NonBlockingSession.java:229) -release connection MySQLConnection [id=19,lastTime=1455443553868, user=root, schema=db1, old shema=db1, borrowed=true,fromSlaveDB=false, threadId=220, charset=latin1, txIsolation=3,autocommit=true, attachment=dn1{SELECT * FROMtravelrecord ORDERBY id LIMIT0, 1000100}, respHandler=org.opencloudb.mysql.nio.handler.MultiNodeQueryHandler@f35a686,host=110.254.11.111, port=3317,statusSync=org.opencloudb.mysql.nio.MySQLConnection$StatusSync@b47af37,writeQueue=0, modifiedSQLExecuted=false] 02/1417:52:33.886 DEBUG [$_NIOREACTOR-3-RW](PhysicalDatasource.java:403) -release channel MySQLConnection [id=19,lastTime=1455443553868, user=root, schema=db1, old shema=db1, borrowed=true,fromSlaveDB=false, threadId=220, charset=latin1, txIsolation=3,autocommit=true, attachment=null, respHandler=null, host=110.254.11.111, port=3317,statusSync=null, writeQueue=0, modifiedSQLExecuted=false] 02/1417:52:33.886 DEBUG [$_NIOREACTOR-3-RW](MultiNodeQueryHandler.java:241) -on row end reseponse MySQLConnection [id=42,lastTime=1455443553868, user=root, schema=db2, old shema=db2, borrowed=true,fromSlaveDB=false, threadId=234, charset=latin1, txIsolation=3,autocommit=true, attachment=dn2{SELECT * FROMtravelrecord ORDERBY id LIMIT0, 1000100},respHandler=org.opencloudb.mysql.nio.handler.MultiNodeQueryHandler@f35a686,host=110.254.11.111, port=3317, statusSync=null, writeQueue=0,modifiedSQLExecuted=false] 02/1417:52:33.886 DEBUG [$_NIOREACTOR-3-RW](NonBlockingSession.java:229) -release connection MySQLConnection [id=42,lastTime=1455443553868, user=root, schema=db2, old shema=db2, borrowed=true,fromSlaveDB=false, threadId=234, charset=latin1, txIsolation=3,autocommit=true, attachment=dn2{SELECT * FROMtravelrecord ORDERBY id LIMIT0, 1000100},respHandler=org.opencloudb.mysql.nio.handler.MultiNodeQueryHandler@f35a686, host=110.254.11.111,port=3317, statusSync=null, writeQueue=0, modifiedSQLExecuted=false] 02/1417:52:33.886 DEBUG [$_NIOREACTOR-3-RW](PhysicalDatasource.java:403) -release channel MySQLConnection [id=42,lastTime=1455443553868, user=root, schema=db2, old shema=db2, borrowed=true,fromSlaveDB=false, threadId=234, charset=latin1, txIsolation=3,autocommit=true, attachment=null, respHandler=null, host=110.254.11.111,port=3317, statusSync=null, writeQueue=0, modifiedSQLExecuted=false] 02/1417:52:33.887 DEBUG [BusinessExecutor5](DataMergeService.java:296) -prepare mpp merge result for select * fromtravelrecord order by id limit 1000000,100 02/1417:52:33.887 DEBUG [BusinessExecutor5](MultiNodeQueryHandler.java:324) -last packet id:8路由里面是先查limit 0,1000000条，然后再查出limit 0,1000100条记录，在这个基础上查出100条（prepare mpp mergeresult for select * from travelrecord order by id limit 1000000,100），所以如果这个M=1000000越来越大，一次性拉的数据就越大，这样就越来越慢了，那么需要查询的数据就比较多
２结合Mycat日志，分析跨分片事务的执行过程，以一个正常的跨分片SQL的事务过程，以及,一个错误SQL为例（比如某个分片上主键冲突或其他ＳＱＬ错误，导致无法执行成功）分别加, 以说明
２结合Mycat日志，分析跨分片事务的执行过程，以一个正常的跨分片SQL的事务过程，以及,一个错误SQL为例（比如某个分片上主键冲突或其他ＳＱＬ错误，导致无法执行成功）分别加, 以说明2.1 正常的跨分片事务分析
2.1 正常的跨分片事务分析执行情况：
mysql>set autocommit=0 mysql>update order040302 set SN=concat(SN,'-mycat'); QueryOK, 2 rows affected (0.01 sec) Rowsmatched: 1 Changed: 1 Warnings: 0 mysql>commit;mycat.log日志显示：
02/1800:01:24.351 DEBUG [$_NIOREACTOR-1-RW](ServerQueryHandler.java:56) -ServerConnection [id=4, schema=TESTDB,host=127.0.0.1, user=test,txIsolation=3, autocommit=true, schema=TESTDB]updateorder040302 set SN=concat(SN,'-mycat') 02/1800:01:24.356 DEBUG [$_NIOREACTOR-1-RW](NonBlockingSession.java:113) -ServerConnection [id=4, schema=TESTDB,host=127.0.0.1, user=test,txIsolation=3, autocommit=true, schema=TESTDB]updateorder040302 set SN=concat(SN,'-mycat'), route={ 1 -> dn21{update order040302 setSN=concat(SN,'-mycat')} 2 -> dn22{update order040302 setSN=concat(SN,'-mycat')} }rrs 02/1800:01:24.356 DEBUG [$_NIOREACTOR-1-RW](MultiNodeQueryHandler.java:82) -execute mutinode query update order040302 setSN=concat(SN,'-mycat') 02/1800:01:24.357 DEBUG [$_NIOREACTOR-3-RW](MultiNodeQueryHandler.java:171) -received ok response ,executeResponse:falsefrom MySQLConnection [id=7, lastTime=1455724884356, user=root, schema=db3, oldshema=db3, borrowed=true, fromSlaveDB=false, threadId=218, charset=latin1,txIsolation=3, autocommit=true, attachment=dn21{update order040302 setSN=concat(SN,'-mycat')},respHandler=org.opencloudb.mysql.nio.handler.MultiNodeQueryHandler@23eca0d1,host=110.254.11.111, port=3317, statusSync=org.opencloudb.mysql.nio.MySQLConnection$StatusSync@71a27302,writeQueue=0, modifiedSQLExecuted=true] 02/1800:01:24.358 DEBUG [$_NIOREACTOR-2-RW](MultiNodeQueryHandler.java:171) -received ok response ,executeResponse:truefrom MySQLConnection [id=30, lastTime=1455724884356, user=root, schema=db3, oldshema=db3, borrowed=true, fromSlaveDB=false, threadId=200, charset=latin1,txIsolation=3, autocommit=true, attachment=dn22{update order040302 setSN=concat(SN,'-mycat')},respHandler=org.opencloudb.mysql.nio.handler.MultiNodeQueryHandler@23eca0d1,host=110.254.11.111, port=3327, statusSync=null, writeQueue=0,modifiedSQLExecuted=true] 02/1800:01:24.359 DEBUG [$_NIOREACTOR-2-RW](NonBlockingSession.java:229) -release connection MySQLConnection [id=30,lastTime=1455724884356, user=root, schema=db3, old shema=db3, borrowed=true,fromSlaveDB=false, threadId=200, charset=latin1, txIsolation=3,autocommit=true, attachment=dn22{update order040302 setSN=concat(SN,'-mycat')},respHandler=org.opencloudb.mysql.nio.handler.MultiNodeQueryHandler@23eca0d1,host=110.254.11.111, port=3327, statusSync=null, writeQueue=0,modifiedSQLExecuted=true] 02/1800:01:24.359 DEBUG [$_NIOREACTOR-3-RW](MultiNodeQueryHandler.java:171) -received ok response ,executeResponse:truefrom MySQLConnection [id=7, lastTime=1455724884356, user=root, schema=db3, oldshema=db3, borrowed=true, fromSlaveDB=false, threadId=218, charset=latin1,txIsolation=3, autocommit=true, attachment=dn21{update order040302 setSN=concat(SN,'-mycat')}, respHandler=org.opencloudb.mysql.nio.handler.MultiNodeQueryHandler@23eca0d1,host=110.254.11.111, port=3317, statusSync=null, writeQueue=0,modifiedSQLExecuted=true] 02/1800:01:24.359 DEBUG [$_NIOREACTOR-3-RW](NonBlockingSession.java:229) -release connection MySQLConnection [id=7,lastTime=1455724884356, user=root, schema=db3, old shema=db3, borrowed=true,fromSlaveDB=false, threadId=218, charset=latin1, txIsolation=3,autocommit=true, attachment=dn21{update order040302 setSN=concat(SN,'-mycat')}, respHandler=org.opencloudb.mysql.nio.handler.MultiNodeQueryHandler@23eca0d1,host=110.254.11.111, port=3317, statusSync=null, writeQueue=0,modifiedSQLExecuted=true] 02/1800:01:24.359 DEBUG [$_NIOREACTOR-3-RW](PhysicalDatasource.java:403) -release channel MySQLConnection [id=7,lastTime=1455724884356, user=root, schema=db3, old shema=db3, borrowed=true,fromSlaveDB=false, threadId=218, charset=latin1, txIsolation=3,autocommit=true, attachment=null, respHandler=null, host=110.254.11.111,port=3317, statusSync=null, writeQueue=0, modifiedSQLExecuted=false]分析结果：update语句是修改所有的节点上的数据，02/18 00:01:24.356处NonBlockingSession启动了分布式事务，下面就分别在02/18 00:01:24.359有2处 NonBlockingSession.java:229在dn21、dn22上面执行了2遍，大家看到在2个节点dn21和dn22都执行完毕后，才有(PhysicalDatasource.java:403)-release channel MySQLConnection开始关闭释放连接，也就是说等所有节点都执行完毕后才结束整个事务。
2.2 非正常的sql事务执行，有一处报错的情况下（失败经过）
2.2 非正常的sql事务执行，有一处报错的情况下（失败经过） 准备数据，需要一个节点成功，一个节点失败，所以准备拿SN字段的长度来做实验，一个超过报错，一个没有超过不报错2.2.1 查看表结构：
2.2.1 查看表结构： mysql>show create table order040302;+-------------+---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+ |Table | Create Table |+-------------+---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+ |order040302 | CREATE TABLE `order040302` ( `ID` int(11) NOT NULL AUTO_INCREMENT, `CODE` varchar(64) DEFAULT NULL, `SN` varchar(64) DEFAULT NULL, `CREATE_TIME` datetime DEFAULT NULL, PRIMARY KEY (`ID`) )ENGINE=InnoDB AUTO_INCREMENT=3 DEFAULT CHARSET=utf8mb4 |+-------------+---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+ 1row in set (0.00 sec) mysql>修改数据，设置成如此，一会就可以update一个节点失败一个节点成功了，在ID=1的节点上因为长度超过64报错，而在ID=2的节点上面则长度小于64而正常执行：
mysql> update order040302 set SN =concat('',SN,'___',SN) where ID=1; QueryOK, 1 row affected (0.01 sec) Rowsmatched: 1 Changed: 1 Warnings: 0 mysql>select length(t1.SN),t1.* from order040302 t1; +---------------+----+------------+-------------------------------------------------------+---------------------+ |length(t1.SN) | ID | CODE | SN | CREATE_TIME | +---------------+----+------------+-------------------------------------------------------+---------------------+ | 53 | 1 | 0-10000020 |beijing_03-10000020-mycat___beijing_03-10000020-mycat | 2016-02-13 00:40:27 | | 26 | 2 | 1-10000020 |shanghai_10-10000020-mycat | 2016-02-1300:40:18 | +---------------+----+------------+-------------------------------------------------------+---------------------+ 2rows in set (0.00 sec)mysql> update order040302 set SN =concat('fenpianyigechenggong_yigeshibai_',SN) ;2.2.2 mycat.log日志如下：
2.2.2 mycat.log日志如下： 02/2205:44:39.666 DEBUG [$_NIOREACTOR-0-RW](ServerQueryHandler.java:56) -ServerConnection [id=1, schema=TESTDB,host=127.0.0.1, user=test,txIsolation=3, autocommit=true, schema=TESTDB]updateorder040302 set SN = concat('fenpianyigechenggong_yigeshibai_',SN) 02/2205:44:39.821 DEBUG [$_NIOREACTOR-0-RW](NonBlockingSession.java:113) -ServerConnection [id=1, schema=TESTDB,host=127.0.0.1, user=test,txIsolation=3, autocommit=true, schema=TESTDB]updateorder040302 set SN = concat('fenpianyigechenggong_yigeshibai_',SN), route={ 1 -> dn21{update order040302 set SN =concat('fenpianyigechenggong_yigeshibai_',SN)} 2 -> dn22{update order040302 set SN =concat('fenpianyigechenggong_yigeshibai_',SN)} }rrs 02/2205:44:39.827 DEBUG [$_NIOREACTOR-0-RW](MultiNodeQueryHandler.java:82) -execute mutinode query update order040302 setSN = concat('fenpianyigechenggong_yigeshibai_',SN) 02/2205:44:39.830 DEBUG [$_NIOREACTOR-3-RW](MultiNodeQueryHandler.java:171) -received ok response ,executeResponse:falsefrom MySQLConnection [id=7, lastTime=1456091079827, user=root, schema=db3, oldshema=db3, borrowed=true, fromSlaveDB=false, threadId=245, charset=latin1,txIsolation=3, autocommit=true, attachment=dn21{update order040302 set SN =concat('fenpianyigechenggong_yigeshibai_',SN)},respHandler=org.opencloudb.mysql.nio.handler.MultiNodeQueryHandler@1c70f0b1,host=110.254.11.111, port=3317, statusSync=org.opencloudb.mysql.nio.MySQLConnection$StatusSync@64b49aaa,writeQueue=0, modifiedSQLExecuted=true] 02/2205:44:39.831 DEBUG [$_NIOREACTOR-0-RW](MultiNodeQueryHandler.java:171) -received ok response ,executeResponse:falsefrom MySQLConnection [id=12, lastTime=1456091079827, user=root, schema=db3, oldshema=db3, borrowed=true, fromSlaveDB=false, threadId=222, charset=latin1,txIsolation=3, autocommit=true, attachment=dn22{update order040302 set SN =concat('fenpianyigechenggong_yigeshibai_',SN)}, respHandler=org.opencloudb.mysql.nio.handler.MultiNodeQueryHandler@1c70f0b1,host=110.254.11.111, port=3327,statusSync=org.opencloudb.mysql.nio.MySQLConnection$StatusSync@306b3db1,writeQueue=0, modifiedSQLExecuted=true] 02/2205:44:39.831 DEBUG [$_NIOREACTOR-3-RW](NonBlockingSession.java:229) -release connection MySQLConnection [id=7,lastTime=1456091079827, user=root, schema=db3, old shema=db3, borrowed=true,fromSlaveDB=false, threadId=245, charset=latin1, txIsolation=3,autocommit=true, attachment=dn21{update order040302 set SN =concat('fenpianyigechenggong_yigeshibai_',SN)},respHandler=org.opencloudb.mysql.nio.handler.MultiNodeQueryHandler@1c70f0b1,host=110.254.11.111, port=3317,statusSync=org.opencloudb.mysql.nio.MySQLConnection$StatusSync@64b49aaa,writeQueue=0, modifiedSQLExecuted=true] 02/2205:44:39.832 DEBUG [$_NIOREACTOR-3-RW](PhysicalDatasource.java:403) -release channel MySQLConnection [id=7,lastTime=1456091079827, user=root, schema=db3, old shema=db3, borrowed=true,fromSlaveDB=false, threadId=245, charset=latin1, txIsolation=3,autocommit=true, attachment=null, respHandler=null, host=110.254.11.111,port=3317, statusSync=null, writeQueue=0, modifiedSQLExecuted=false] 02/2205:44:39.832 DEBUG [$_NIOREACTOR-0-RW](MultiNodeQueryHandler.java:171) -received ok response ,executeResponse:truefrom MySQLConnection [id=12, lastTime=1456091079827, user=root, schema=db3, oldshema=db3, borrowed=true, fromSlaveDB=false, threadId=222, charset=latin1,txIsolation=3, autocommit=true, attachment=dn22{update order040302 set SN =concat('fenpianyigechenggong_yigeshibai_',SN)},respHandler=org.opencloudb.mysql.nio.handler.MultiNodeQueryHandler@1c70f0b1,host=110.254.11.111, port=3327, statusSync=null, writeQueue=0,modifiedSQLExecuted=true] 02/2205:44:39.832 WARN [$_NIOREACTOR-3-RW](MultiNodeHandler.java:127) -error response from MySQLConnection [id=7,lastTime=1456091079827, user=root, schema=db3, old shema=db3, borrowed=false,fromSlaveDB=false, threadId=245, charset=latin1, txIsolation=3,autocommit=true, attachment=null, respHandler=null, host=110.254.11.111,port=3317, statusSync=null, writeQueue=0, modifiedSQLExecuted=false] err Datatoo long for column 'SN' at row 1 code:1406 02/2205:44:39.833 DEBUG [$_NIOREACTOR-0-RW](NonBlockingSession.java:229) -release connection MySQLConnection [id=12,lastTime=1456091079827, user=root, schema=db3, old shema=db3, borrowed=true,fromSlaveDB=false, threadId=222, charset=latin1, txIsolation=3,autocommit=true, attachment=dn22{update order040302 set SN =concat('fenpianyigechenggong_yigeshibai_',SN)},respHandler=org.opencloudb.mysql.nio.handler.MultiNodeQueryHandler@1c70f0b1,host=110.254.11.111, port=3327, statusSync=null, writeQueue=0,modifiedSQLExecuted=true] 02/2205:44:39.834 DEBUG [$_NIOREACTOR-0-RW](PhysicalDatasource.java:403) -release channel MySQLConnection [id=12,lastTime=1456091079827, user=root, schema=db3, old shema=db3, borrowed=true,fromSlaveDB=false, threadId=222, charset=latin1, txIsolation=3,autocommit=true, attachment=null, respHandler=null, host=110.254.11.111, port=3327,statusSync=null, writeQueue=0, modifiedSQLExecuted=false] 02/2205:44:39.835 DEBUG [$_NIOREACTOR-0-RW](MultiNodeHandler.java:194) -error all end ,clear session resource从日志记录里面可以看出：[
mysql>select length(t1.SN),t1.* from order040302 t1; +---------------+----+------------+------------------------------------------------------------+---------------------+ |length(t1.SN) | ID | CODE | SN | CREATE_TIME | +---------------+----+------------+------------------------------------------------------------+---------------------+ | 53 | 1 | 0-10000020 |beijing_03-10000020-mycat___beijing_03-10000020-mycat | 2016-02-13 00:40:27 | | 58 | 2 | 1-10000020 |fenpianyigechenggong_yigeshibai_shanghai_10-10000020-mycat | 2016-02-1300:40:18 | +---------------+----+------------+------------------------------------------------------------+---------------------+ 2rows in set (0.06 sec) mysql> 可见，我这个不是事务，事务会所有一起回退的。mycat窗口中如何开启事务？2.3 如何mysql窗口那样，在mycat窗口开启事务
2.3 如何mysql窗口那样，在mycat窗口开启事务2.3.1 开启事务，手动提交
2.3.1 开启事务，手动提交 mysql>set autocommit=0; QueryOK, 0 rows affected (0.00 sec) mysql>update order040302 set SN = concat('fenpianyigechenggong_yigeshibai_',SN) ; ERROR1105 (HY000): Data too long for column 'SN' at row 1 mysql>commit; ERROR1003 (HY000): Transaction error, need to rollback. mysql> mysql>select length(t1.SN),t1.* from order040302 t1; ERROR1003 (HY000): Transaction error, need to rollback.Data too long for column 'SN'at row 1 mysql> mysql>rollback; QueryOK, 0 rows affected (0.01 sec) mysql> mysql>select length(t1.SN),t1.* from order040302 t1; +---------------+----+------------+-------------------------------------------------------+---------------------+ |length(t1.SN) | ID | CODE | SN | CREATE_TIME | +---------------+----+------------+-------------------------------------------------------+---------------------+ | 53 | 1 | 0-10000020 |beijing_03-10000020-mycat___beijing_03-10000020-mycat | 2016-02-13 00:40:27 | | 26 | 2 | 1-10000020 |shanghai_10-10000020-mycat | 2016-02-1300:40:18 | +---------------+----+------------+-------------------------------------------------------+---------------------+ 2rows in set (0.09 sec) mysql>2.3.2 后台mycat.log日志如下，run失败信息如下：
2.3.2 后台mycat.log日志如下，run失败信息如下： 02/2217:54:25.035 DEBUG [$_NIOREACTOR-1-RW](ServerQueryHandler.java:56) -ServerConnection [id=2, schema=TESTDB,host=127.0.0.1, user=test,txIsolation=3, autocommit=false, schema=TESTDB]updateorder040302 set SN = concat('fenpianyigechenggong_yigeshibai_',SN) 02/2217:54:25.187 DEBUG [$_NIOREACTOR-1-RW](NonBlockingSession.java:113) -ServerConnection [id=2, schema=TESTDB, host=127.0.0.1,user=test,txIsolation=3, autocommit=false, schema=TESTDB]update order040302 setSN = concat('fenpianyigechenggong_yigeshibai_',SN), route={ 1 -> dn21{update order040302 set SN =concat('fenpianyigechenggong_yigeshibai_',SN)} 2 -> dn22{update order040302 set SN =concat('fenpianyigechenggong_yigeshibai_',SN)} }rrs 02/2217:54:25.193 DEBUG [$_NIOREACTOR-1-RW](MultiNodeQueryHandler.java:82) -execute mutinode query update order040302 setSN = concat('fenpianyigechenggong_yigeshibai_',SN) 02/2217:54:25.195 DEBUG [$_NIOREACTOR-3-RW](MultiNodeQueryHandler.java:171) -received ok response ,executeResponse:falsefrom MySQLConnection [id=7, lastTime=1456134865193, user=root, schema=db3, oldshema=db3, borrowed=true, fromSlaveDB=false, threadId=278, charset=latin1,txIsolation=0, autocommit=true, attachment=dn21{update order040302 set SN =concat('fenpianyigechenggong_yigeshibai_',SN)},respHandler=org.opencloudb.mysql.nio.handler.MultiNodeQueryHandler@243cc381,host=110.254.11.111, port=3317, statusSync=org.opencloudb.mysql.nio.MySQLConnection$StatusSync@4ff5e91e,writeQueue=0, modifiedSQLExecuted=true] 02/2217:54:25.196 DEBUG [$_NIOREACTOR-1-RW](MultiNodeQueryHandler.java:171) -received ok response ,executeResponse:falsefrom MySQLConnection [id=17, lastTime=1456134865193, user=root, schema=db3, oldshema=db3, borrowed=true, fromSlaveDB=false, threadId=259, charset=latin1,txIsolation=0, autocommit=true, attachment=dn22{update order040302 set SN =concat('fenpianyigechenggong_yigeshibai_',SN)},respHandler=org.opencloudb.mysql.nio.handler.MultiNodeQueryHandler@243cc381,host=110.254.11.111, port=3327,statusSync=org.opencloudb.mysql.nio.MySQLConnection$StatusSync@46e9d255,writeQueue=0, modifiedSQLExecuted=true] 02/2217:54:25.196 DEBUG [$_NIOREACTOR-3-RW](MultiNodeQueryHandler.java:171) -received ok response ,executeResponse:falsefrom MySQLConnection [id=7, lastTime=1456134865193, user=root, schema=db3, oldshema=db3, borrowed=true, fromSlaveDB=false, threadId=278, charset=latin1,txIsolation=3, autocommit=false, attachment=dn21{update order040302 set SN =concat('fenpianyigechenggong_yigeshibai_',SN)},respHandler=org.opencloudb.mysql.nio.handler.MultiNodeQueryHandler@243cc381,host=110.254.11.111, port=3317, statusSync=org.opencloudb.mysql.nio.MySQLConnection$StatusSync@4ff5e91e,writeQueue=0, modifiedSQLExecuted=true] 02/2217:54:25.196 DEBUG [$_NIOREACTOR-1-RW](MultiNodeQueryHandler.java:171) -received ok response ,executeResponse:falsefrom MySQLConnection [id=17, lastTime=1456134865193, user=root, schema=db3, oldshema=db3, borrowed=true, fromSlaveDB=false, threadId=259, charset=latin1,txIsolation=3, autocommit=false, attachment=dn22{update order040302 set SN =concat('fenpianyigechenggong_yigeshibai_',SN)}, respHandler=org.opencloudb.mysql.nio.handler.MultiNodeQueryHandler@243cc381,host=110.254.11.111, port=3327,statusSync=org.opencloudb.mysql.nio.MySQLConnection$StatusSync@46e9d255,writeQueue=0, modifiedSQLExecuted=true] 02/2217:54:25.197 WARN [$_NIOREACTOR-3-RW](MultiNodeHandler.java:127) -error response from MySQLConnection [id=7,lastTime=1456134865193, user=root, schema=db3, old shema=db3, borrowed=true,fromSlaveDB=false, threadId=278, charset=latin1, txIsolation=3,autocommit=false, attachment=dn21{update order040302 set SN = concat('fenpianyigechenggong_yigeshibai_',SN)},respHandler=org.opencloudb.mysql.nio.handler.MultiNodeQueryHandler@243cc381,host=110.254.11.111, port=3317,statusSync=org.opencloudb.mysql.nio.MySQLConnection$StatusSync@4ff5e91e,writeQueue=0, modifiedSQLExecuted=true] err Data too long for column 'SN' atrow 1 code:1406 02/2217:54:25.197 DEBUG [$_NIOREACTOR-1-RW](MultiNodeQueryHandler.java:171) -received ok response ,executeResponse:truefrom MySQLConnection [id=17, lastTime=1456134865193, user=root, schema=db3, oldshema=db3, borrowed=true, fromSlaveDB=false, threadId=259, charset=latin1,txIsolation=3, autocommit=false, attachment=dn22{update order040302 set SN =concat('fenpianyigechenggong_yigeshibai_',SN)},respHandler=org.opencloudb.mysql.nio.handler.MultiNodeQueryHandler@243cc381,host=110.254.11.111, port=3327, statusSync=null, writeQueue=0,modifiedSQLExecuted=true] 02/2217:54:25.199 DEBUG [$_NIOREACTOR-1-RW](MultiNodeHandler.java:194) -error all end ,clear session resource 2.3.3后台mycat.log日志，rollback操作日志如下：
2.3.3后台mycat.log日志，rollback操作日志如下： 02/2217:57:17.432 DEBUG [$_NIOREACTOR-1-RW](ServerQueryHandler.java:56) -ServerConnection [id=2, schema=TESTDB,host=127.0.0.1, user=test,txIsolation=3, autocommit=false,schema=TESTDB]rollback 02/2217:57:17.434 DEBUG [$_NIOREACTOR-1-RW] (RollbackNodeHandler.java:71)-rollback job run for MySQLConnection [id=7, lastTime=1456134865193, user=root,schema=db3, old shema=db3, borrowed=true, fromSlaveDB=false, threadId=278,charset=latin1, txIsolation=3, autocommit=false, attachment=dn21{updateorder040302 set SN = concat('fenpianyigechenggong_yigeshibai_',SN)},respHandler=org.opencloudb.mysql.nio.handler.MultiNodeQueryHandler@243cc381,host=110.254.11.111, port=3317,statusSync=org.opencloudb.mysql.nio.MySQLConnection$StatusSync@4ff5e91e,writeQueue=0, modifiedSQLExecuted=true] 02/2217:57:17.435 DEBUG [$_NIOREACTOR-1-RW](RollbackNodeHandler.java:71) -rollback job run for MySQLConnection [id=17,lastTime=1456134865193, user=root, schema=db3, old shema=db3, borrowed=true,fromSlaveDB=false, threadId=259, charset=latin1, txIsolation=3,autocommit=false, attachment=dn22{update order040302 set SN =concat('fenpianyigechenggong_yigeshibai_',SN)},respHandler=org.opencloudb.mysql.nio.handler.MultiNodeQueryHandler@243cc381,host=110.254.11.111, port=3327, statusSync=null, writeQueue=0,modifiedSQLExecuted=true] 02/2217:57:17.436 DEBUG [$_NIOREACTOR-1-RW](NonBlockingSession.java:361) -clear session resourcesorg.opencloudb.server.NonBlockingSession@4483dae0 02/2217:57:17.436 DEBUG [$_NIOREACTOR-1-RW](NonBlockingSession.java:229) -release connection MySQLConnection [id=7,lastTime=1456134865193, user=root, schema=db3, old shema=db3, borrowed=true,fromSlaveDB=false, threadId=278, charset=latin1, txIsolation=3,autocommit=false, attachment=dn21{update order040302 set SN =concat('fenpianyigechenggong_yigeshibai_',SN)},respHandler=org.opencloudb.mysql.nio.handler.RollbackNodeHandler@2c96cb44,host=110.254.11.111, port=3317, statusSync=org.opencloudb.mysql.nio.MySQLConnection$StatusSync@4ff5e91e,writeQueue=0, modifiedSQLExecuted=true] 02/2217:57:17.438 DEBUG [$_NIOREACTOR-1-RW](NonBlockingSession.java:229) -release connection MySQLConnection [id=17,lastTime=1456134865193, user=root, schema=db3, old shema=db3, borrowed=true,fromSlaveDB=false, threadId=259, charset=latin1, txIsolation=3,autocommit=false, attachment=dn22{update order040302 set SN =concat('fenpianyigechenggong_yigeshibai_',SN)},respHandler=org.opencloudb.mysql.nio.handler.RollbackNodeHandler@2c96cb44,host=110.254.11.111, port=3327, statusSync=null, writeQueue=0,modifiedSQLExecuted=true] 02/2217:57:17.438 DEBUG [$_NIOREACTOR-3-RW](RollbackReleaseHandler.java:58) -autocomit is false,but no commit or rollback,so mycat rollbacked backend conn MySQLConnection [id=7,lastTime=1456134865193, user=root, schema=db3, old shema=db3, borrowed=true,fromSlaveDB=false, threadId=278, charset=latin1, txIsolation=3,autocommit=false, attachment=null,respHandler=org.opencloudb.mysql.nio.handler.RollbackReleaseHandler@56683a8d,host=110.254.11.111, port=3317,statusSync=org.opencloudb.mysql.nio.MySQLConnection$StatusSync@4ff5e91e,writeQueue=0, modifiedSQLExecuted=true] 02/2217:57:17.439 DEBUG [$_NIOREACTOR-3-RW](PhysicalDatasource.java:403) -release channel MySQLConnection [id=7,lastTime=1456134865193, user=root, schema=db3, old shema=db3, borrowed=true,fromSlaveDB=false, threadId=278, charset=latin1, txIsolation=3,autocommit=false, attachment=null, respHandler=null, host=110.254.11.111,port=3317, statusSync=null, writeQueue=0, modifiedSQLExecuted=false] 02/2217:57:17.439 DEBUG [$_NIOREACTOR-1-RW](RollbackReleaseHandler.java:58) -autocomit is false,but no commit or rollback,so mycat rollbacked backend conn MySQLConnection [id=17,lastTime=1456134865193, user=root, schema=db3, old shema=db3, borrowed=true,fromSlaveDB=false, threadId=259, charset=latin1, txIsolation=3,autocommit=false, attachment=null,respHandler=org.opencloudb.mysql.nio.handler.RollbackReleaseHandler@429eb61a,host=110.254.11.111, port=3327, statusSync=null, writeQueue=0,modifiedSQLExecuted=true] 02/2217:57:17.440 DEBUG [$_NIOREACTOR-1-RW](PhysicalDatasource.java:403) -release channel MySQLConnection [id=17,lastTime=1456134865193, user=root, schema=db3, old shema=db3, borrowed=true,fromSlaveDB=false, threadId=259, charset=latin1, txIsolation=3,autocommit=false, attachment=null, respHandler=null, host=110.254.11.111,port=3327, statusSync=null, writeQueue=0, modifiedSQLExecuted=false]看到在执行update的时候，有报错信息：在dn21节点上面err Data too long forcolumn ‘SN’ at row 1 code:1406，所以按照理论上任何节点发生错误了，就面临rollback的错误信息，任何任何都会提示报错信息，只能执行rollback来恢复。PS：这里目前的mycat版本没有办法做到在update失败后自动rollback，需要手动rollback操作。
３创建一个在多个分片上存在的存储过程，存储过程可以是统计某个表的记录个数并返回，然后用Mycat注解方式完成调用
３创建一个在多个分片上存在的存储过程，存储过程可以是统计某个表的记录个数并返回，然后用Mycat注解方式完成调用3.1准备好的简单的存储过程
3.1准备好的简单的存储过程 DELIMITER$$ CREATE PROCEDUREdb3.pro_select() BEGIN SELECTCOUNT(1) FROM order040302; END$$ DELIMITER;3.2在各mysql节点上执行创建存储过程
3.2在各mysql节点上执行创建存储过程dn21节点上的mysql窗口上：
mysql>DELIMITER $$ mysql>CREATE -> PROCEDURE `db3`.`pro_select`() -> BEGIN ->SELECT COUNT(1) FROM order040302; -> END$$ QueryOK, 0 rows affected (0.01 sec) mysql>DELIMITER ; mysql>dn22节点上的mysql窗口上：
mysql>DELIMITER $$ mysql>CREATE -> PROCEDURE `db3`.`pro_select`() -> BEGIN ->SELECT COUNT(1) FROM order040302; -> END$$ QueryOK, 0 rows affected (0.01 sec) mysql>DELIMITER ; mysql>检查存储过程：
mysql>select * from information_schema.ROUTINES\G ***************************1. row *************************** SPECIFIC_NAME: pro_select ROUTINE_CATALOG: def ROUTINE_SCHEMA: db3 ROUTINE_NAME:pro_select ROUTINE_TYPE:PROCEDURE DATA_TYPE: CHARACTER_MAXIMUM_LENGTH:NULL CHARACTER_OCTET_LENGTH: NULL NUMERIC_PRECISION: NULL NUMERIC_SCALE: NULL DATETIME_PRECISION: NULL CHARACTER_SET_NAME: NULL COLLATION_NAME: NULL DTD_IDENTIFIER: NULL ROUTINE_BODY:SQL ROUTINE_DEFINITION: BEGIN SELECTCOUNT(1) FROM order040302; END EXTERNAL_NAME: NULL EXTERNAL_LANGUAGE: NULL PARAMETER_STYLE: SQL IS_DETERMINISTIC: NO SQL_DATA_ACCESS: ConTAINS SQL SQL_PATH:NULL SECURITY_TYPE: DEFINER CREATED: 2016-02-22 19:17:12 LAST_ALTERED:2016-02-22 19:17:12 SQL_MODE:STRICT_TRANS_TABLES,NO_ENGINE_SUBSTITUTION ROUTINE_COMMENT: DEFINER: root@localhost CHARACTER_SET_CLIENT:latin1 COLLATION_CONNECTION:latin1_swedish_ci DATAbase_COLLATION: utf8mb4_general_ci 1row in set (0.00 sec) mysql>然后在mycat中执行：
mysql> call pro_select(); +----------+ |COUNT(1) | +----------+ | 1 | | 1 | +----------+ 2rows in set (0.01 sec) QueryOK, 0 rows affected (0.01 sec) mysql>问题，为啥是2行记录，不知道可以不可以并成一行记录呢？
普通sql到了最后会有如下：
02/23 00:07:21.478 DEBUG [BusinessExecutor0] (DataMergeService.java:296) -prepare mpp merge result for select count(*) from order04030202/23 00:07:21.479 DEBUG [BusinessExecutor0] (MultiNodeQueryHandler.java:324) -last packet id:5的聚合操作，有了这个merge result操作后，就会把2条记录变成一条记录，但是mycat注解后的执行sql显示注解后，没有这一个merge result的操作，所以是2条记录。哇塞，我好伟大，发现了其中的区别，但是那么新问题来了，怎么完善注解后生成的2条记录变成为1条记录额？
3.3看后台mycat.log日志：
3.3看后台mycat.log日志：看到日志中42.293记录，走的route路由进入dn21和dn22节点上面，最终执行的是注解的-execute mutinode query select * from order040302，如下所示：
02/22 20:19:42.292 DEBUG [$_NIOREACTOR-1-RW](ServerQueryHandler.java:56) -ServerConnection [id=10, schema=TESTDB,host=127.0.0.1, user=test,txIsolation=3, autocommit=true,schema=TESTDB] call pro_select() 02/22 20:19:42.293 DEBUG [$_NIOREACTOR-1-RW](NonBlockingSession.java:113) -ServerConnection [id=10, schema=TESTDB,host=127.0.0.1, user=test,txIsolation=3, autocommit=true, schema=TESTDB]select* from order040302, route={ 1 -> dn21{call pro_select()} 2 -> dn22{call pro_select()} } rrs 02/22 20:19:42.293 DEBUG [$_NIOREACTOR-1-RW](MultiNodeQueryHandler.java:82) -execute mutinode query select * fromorder040302 02/2220:19:42.295 DEBUG [$_NIOREACTOR-0-RW](MultiNodeQueryHandler.java:171) -received ok response ,executeResponse:falsefrom MySQLConnection [id=4, lastTime=1456143582284, user=root, schema=db3, oldshema=db3, borrowed=true, fromSlaveDB=false, threadId=280, charset=latin1,txIsolation=3, autocommit=true, attachment=dn21{call pro_select()},respHandler=org.opencloudb.mysql.nio.handler.MultiNodeQueryHandler@ba5d1a4,host=110.254.11.111, port=3317,statusSync=org.opencloudb.mysql.nio.MySQLConnection$StatusSync@939bc30,writeQueue=0, modifiedSQLExecuted=true] 02/2220:19:42.295 DEBUG [$_NIOREACTOR-3-RW](MultiNodeQueryHandler.java:241) -on row end reseponse MySQLConnection [id=11,lastTime=1456143582284, user=root, schema=db3, old shema=db3, borrowed=true,fromSlaveDB=false, threadId=254, charset=latin1, txIsolation=3, autocommit=true,attachment=dn22{call pro_select()},respHandler=org.opencloudb.mysql.nio.handler.MultiNodeQueryHandler@ba5d1a4,host=110.254.11.111, port=3327, statusSync=null, writeQueue=0,modifiedSQLExecuted=true] 02/2220:19:42.295 DEBUG [$_NIOREACTOR-0-RW](MultiNodeQueryHandler.java:241) -on row end reseponse MySQLConnection [id=4,lastTime=1456143582284, user=root, schema=db3, old shema=db3, borrowed=true,fromSlaveDB=false, threadId=280, charset=latin1, txIsolation=3,autocommit=true, attachment=dn21{call pro_select()},respHandler=org.opencloudb.mysql.nio.handler.MultiNodeQueryHandler@ba5d1a4,host=110.254.11.111, port=3317,statusSync=org.opencloudb.mysql.nio.MySQLConnection$StatusSync@939bc30,writeQueue=0, modifiedSQLExecuted=true] 02/2220:19:42.296 DEBUG [$_NIOREACTOR-0-RW](MultiNodeQueryHandler.java:280) -last packet id:6 02/2220:19:42.295 DEBUG [$_NIOREACTOR-3-RW](MultiNodeQueryHandler.java:171) -received ok response ,executeResponse:truefrom MySQLConnection [id=11, lastTime=1456143582284, user=root, schema=db3, oldshema=db3, borrowed=true, fromSlaveDB=false, threadId=254, charset=latin1,txIsolation=3, autocommit=true, attachment=dn22{call pro_select()},respHandler=org.opencloudb.mysql.nio.handler.MultiNodeQueryHandler@ba5d1a4,host=110.254.11.111, port=3327, statusSync=null, writeQueue=0,modifiedSQLExecuted=true] 02/2220:19:42.296 DEBUG [$_NIOREACTOR-0-RW](MultiNodeQueryHandler.java:171) -received ok response ,executeResponse:truefrom MySQLConnection [id=4, lastTime=1456143582284, user=root, schema=db3, oldshema=db3, borrowed=true, fromSlaveDB=false, threadId=280, charset=latin1,txIsolation=3, autocommit=true, attachment=dn21{call pro_select()},respHandler=org.opencloudb.mysql.nio.handler.MultiNodeQueryHandler@ba5d1a4,host=110.254.11.111, port=3317, statusSync=null, writeQueue=0,modifiedSQLExecuted=true] 02/2220:19:42.296 DEBUG [$_NIOREACTOR-3-RW](NonBlockingSession.java:229) -release connection MySQLConnection [id=11,lastTime=1456143582284, user=root, schema=db3, old shema=db3, borrowed=true,fromSlaveDB=false, threadId=254, charset=latin1, txIsolation=3,autocommit=true, attachment=dn22{call pro_select()},respHandler=org.opencloudb.mysql.nio.handler.MultiNodeQueryHandler@ba5d1a4,host=110.254.11.111, port=3327, statusSync=null, writeQueue=0,modifiedSQLExecuted=true] 02/2220:19:42.296 DEBUG [$_NIOREACTOR-0-RW](NonBlockingSession.java:229) -release connection MySQLConnection [id=4,lastTime=1456143582284, user=root, schema=db3, old shema=db3, borrowed=true,fromSlaveDB=false, threadId=280, charset=latin1, txIsolation=3,autocommit=true, attachment=dn21{call pro_select()},respHandler=org.opencloudb.mysql.nio.handler.MultiNodeQueryHandler@ba5d1a4,host=110.254.11.111, port=3317, statusSync=null, writeQueue=0,modifiedSQLExecuted=true] 02/2220:19:42.296 DEBUG [$_NIOREACTOR-3-RW](PhysicalDatasource.java:403) -release channel MySQLConnection [id=11,lastTime=1456143582284, user=root, schema=db3, old shema=db3, borrowed=true,fromSlaveDB=false, threadId=254, charset=latin1, txIsolation=3,autocommit=true, attachment=null, respHandler=null, host=110.254.11.111, port=3327,statusSync=null, writeQueue=0, modifiedSQLExecuted=false] 02/2220:19:42.297 DEBUG [$_NIOREACTOR-0-RW](PhysicalDatasource.java:403) -release channel MySQLConnection [id=4,lastTime=1456143582284, user=root, schema=db3, old shema=db3, borrowed=true,fromSlaveD**重点内容**B=false, threadId=280, charset=latin1, txIsolation=3,autocommit=true, attachment=null, respHandler=null, host=110.254.11.111,port=3317, statusSync=null, writeQueue=0, modifiedSQLExecuted=false]