1 環境說明
VM 模擬3台MYSQL 5.6 服務器
VM1 192.168.31.187：3307
VM2 192.168.31.212：3307
VM3 192.168.31.150: 3307
MYCAT 1.5 服務部署在宿主機上
MYCAT 192.168.31.207 :8806【SQL執行端口】 / 9066【管理端口】
2 應用場景
2.0 MYCAT配置
schema.xml
<schema name="TESTDB" checkSQLschema="false" sqlMaxLimit="100">
<table name="t_demo_travel_record" dataNode="dn1,dn2,dn3" rule="auto-sharding-long" />
<table name="t_demo_travel_record_child" dataNode="dn1,dn2,dn3" rule="auto-sharding-long" />
</schema>
<dataNode name="dn1" dataHost="vm1" database="test" />
<dataNode name="dn2" dataHost="vm2" database="test" />
<dataNode name="dn3" dataHost="vm3" database="test" />
<dataHost name="vm1" maxCon="1000" minCon="10" balance="0"
writeType="0" dbType="mysql" dbDriver="native" switchType="1" slaveThreshold="100">
<heartbeat>select user()</heartbeat>
<writeHost host="vm1M1" url="192.168.31.187:3307" user="root" password="root123"></writeHost>
</dataHost>
<dataHost name="vm2" maxCon="1000" minCon="10" balance="0"
writeType="0" dbType="mysql" dbDriver="native" switchType="1" slaveThreshold="100">
<heartbeat>select user()</heartbeat>
<writeHost host="vm2M1" url="192.168.31.212:3307" user="root" password="root123"></writeHost>
</dataHost>
<dataHost name="vm3" maxCon="1000" minCon="10" balance="0"
writeType="0" dbType="mysql" dbDriver="native" switchType="1" slaveThreshold="100">
<heartbeat>select user()</heartbeat>
<writeHost host="vm3M1" url="192.168.31.150:3307" user="root" password="root123"></writeHost>
</dataHost>
rule.xml
<tableRule name="auto-sharding-long">
<rule>
<columns>id</columns>
<algorithm>rang-long</algorithm>
</rule>
</tableRule>
<function name="rang-long"
class="org.opencloudb.route.function.AutoPartitionByLong">
<property name="mapFile">autopartition-long.txt</property>
<property name="defaultNode">0</property>
</function>
autopartition-long.txt
# range start-end ,data node index
# K=1000,M=10000.
0-500M=0
500M-1000M=1
1000M-1500M=2
2.1 手動關閉事，跨數據庫進行更新操作。
用一套簡單點的JAVA來做這次數據驗證
DataSource ds = jdbc.getDataSource();
conn = ds.getConnection();
conn.setAutoCommit(false);
pstm1 = conn.prepareStatement("insert into t_demo_travel_record (id,context) values (?,?)");
pstm1.setInt(1, 5000);
pstm1.setString(2, "這條記錄應該進行DN1");
pstm1.addBatch();
pstm1.setInt(1, 5999999);
pstm1.setString(2, "這條記錄應該進行DN2");
pstm1.addBatch();
pstm1.setInt(1, 14991499);
pstm1.setString(2, "這條記錄應該進行DN3");
pstm1.addBatch();
pstm1.executeBatch();
conn.commit();
MYCAT 192.168.31.207: 8806 查詢已插入的記錄
mysql> select * from t_demo_travel_record where id in (5000,5999999,14991499);
+----------+-------------+
| id | context |
+----------+-------------+
| 5000 | ????????DN1 |
| 14991499 | ????????DN3 |
| 5999999 | ????????DN2 |
+----------+-------------+
3 rows in set (0.01 sec)
VM1 192.168.31.187：3307 物理庫
mysql> select * from t_demo_travel_record where id in (5000,5999999,14991499);
+------+-------------+
| id | context |
+------+-------------+
| 5000 | ????????DN1 |
+------+-------------+
1 row in set (0.01 sec)
VM2 192.168.31.212：3307
mysql> select * from t_demo_travel_record where id in (5000,5999999,14991499);
+---------+-------------+
| id | context |
+---------+-------------+
| 5999999 | ????????DN2 |
+---------+-------------+
1 row in set (0.00 sec)
VM3 192.168.31.150: 3307
mysql> select * from t_demo_travel_record where id in (5000,5999999,14991499);
+----------+-------------+
| id | context |
+----------+-------------+
| 14991499 | ????????DN3 |
+----------+-------------+
1 row in set (0.00 sec)
2.2 異常操作，驗證下數據是否回滾
模擬數據如下，最后一條主鍵重復。
pstm1.setInt(1, 5001);
pstm1.setString(2, "這條記錄應該進行DN1");
pstm1.addBatch();
pstm1.setInt(1, 5999998);
pstm1.setString(2, "這條記錄應該進行DN2");
pstm1.addBatch();
pstm1.setInt(1, 14991499);
pstm1.setString(2, "這條記錄應該進行DN3");
pstm1.addBatch();
程序執行報錯：
2016-02-03 00:36:10,229 INFO : [] com.alibaba.druid.pool.DruidDataSource [DruidDataSource.java:669] - {dataSource-1} inited
java.sql.BatchUpdateException: Duplicate entry '14991499' for key 'PRIMARY'
...
再看下數據庫里並沒有執行前2句SQL語句，mycat 在數據分片插入不同的數據庫時已給我們做了一定的數據庫事務控制。
mysql> select * from t_demo_travel_record where id in (5001,5999998,14991499);
+----------+-------------+
| id | context |
+----------+-------------+
| 14991499 | ????????DN3 |
+----------+-------------+
1 row in set (0.01 sec)
再來看下MYCAT日志，根據分片原則，分析將SQL語句發向不同的數據結點
02/03 00:36:10.279 DEBUG [$_NIOREACTOR-1-RW] (ServerQueryHandler.java:56) -ServerConnection [id=31, schema=TESTDB, host=127.0.0.1, user=test,txIsolation=3, autocommit=false, schema=TESTDB]insert into t_demo_travel_record (id,context) values (5001,'這條記錄應該進行DN1')
02/03 00:36:10.279 DEBUG [$_NIOREACTOR-1-RW] (NonBlockingSession.java:113) -ServerConnection [id=31, schema=TESTDB, host=127.0.0.1, user=test,txIsolation=3, autocommit=false, schema=TESTDB]insert into t_demo_travel_record (id,context) values (5001,'這條記錄應該進行DN1'), route={
1 -> dn1{insert into t_demo_travel_record (id,context) values (5001,'這條記錄應該進行DN1')}
} rrs
02/03 00:36:10.281 DEBUG [$_NIOREACTOR-1-RW] (ServerQueryHandler.java:56) -ServerConnection [id=31, schema=TESTDB, host=127.0.0.1, user=test,txIsolation=3, autocommit=false, schema=TESTDB]insert into t_demo_travel_record (id,context) values (5999998,'這條記錄應該進行DN2')
02/03 00:36:10.281 DEBUG [$_NIOREACTOR-1-RW] (NonBlockingSession.java:113) -ServerConnection [id=31, schema=TESTDB, host=127.0.0.1, user=test,txIsolation=3, autocommit=false, schema=TESTDB]insert into t_demo_travel_record (id,context) values (5999998,'這條記錄應該進行DN2'), route={
1 -> dn2{insert into t_demo_travel_record (id,context) values (5999998,'這條記錄應該進行DN2')}
} rrs
02/03 00:36:10.281 DEBUG [$_NIOREACTOR-1-RW] (MySQLConnection.java:445) -con need syn ,total syn cmd 1 commands SET autocommit=0;schema change:false con:MySQLConnection [id=28, lastTime=1454430970281, user=root, schema=test, old shema=test, borrowed=true, fromSlaveDB=false, threadId=30, charset=utf8, txIsolation=3, autocommit=true, attachment=dn2{insert into t_demo_travel_record (id,context) values (5999998,'這條記錄應該進行DN2')}, respHandler=SingleNodeHandler [node=dn2{insert into t_demo_travel_record (id,context) values (5999998,'這條記錄應該進行DN2')}, packetId=0], host=192.168.31.212, port=3307, statusSync=null, writeQueue=0, modifiedSQLExecuted=true]
02/03 00:36:10.284 DEBUG [$_NIOREACTOR-1-RW] (ServerQueryHandler.java:56) -ServerConnection [id=31, schema=TESTDB, host=127.0.0.1, user=test,txIsolation=3, autocommit=false, schema=TESTDB]insert into t_demo_travel_record (id,context) values (14991499,'這條記錄應該進行DN3')
02/03 00:36:10.284 DEBUG [$_NIOREACTOR-1-RW] (NonBlockingSession.java:113) -ServerConnection [id=31, schema=TESTDB, host=127.0.0.1, user=test,txIsolation=3, autocommit=false, schema=TESTDB]insert into t_demo_travel_record (id,context) values (14991499,'這條記錄應該進行DN3'), route={
1 -> dn3{insert into t_demo_travel_record (id,context) values (14991499,'這條記錄應該進行DN3')}
} rrs
准備同步數據庫操作，發現SQL語句在DN3上編譯失敗
02/03 00:36:10.285 DEBUG [$_NIOREACTOR-1-RW] (MySQLConnection.java:445) -con need syn ,total syn cmd 1 commands SET autocommit=0;schema change:false con:MySQLConnection [id=8, lastTime=1454430970285, user=root, schema=test, old shema=test, borrowed=true, fromSlaveDB=false, threadId=24, charset=utf8, txIsolation=3, autocommit=true, attachment=dn3{insert into t_demo_travel_record (id,context) values (14991499,'這條記錄應該進行DN3')}, respHandler=SingleNodeHandler [node=dn3{insert into t_demo_travel_record (id,context) values (14991499,'這條記錄應該進行DN3')}, packetId=0], host=192.168.31.150, port=3307, statusSync=null, writeQueue=0, modifiedSQLExecuted=true]
02/03 00:36:10.286 WARN [$_NIOREACTOR-0-RW] (SingleNodeHandler.java:222) -execute sql err : errno:1062 Duplicate entry '14991499' for key 'PRIMARY' con:MySQLConnection [id=8, lastTime=1454430970269, user=root, schema=test, old shema=test, borrowed=true, fromSlaveDB=false, threadId=24, charset=utf8, txIsolation=3, autocommit=false, attachment=dn3{insert into t_demo_travel_record (id,context) values (14991499,'這條記錄應該進行DN3')}, respHandler=SingleNodeHandler [node=dn3{insert into t_demo_travel_record (id,context) values (14991499,'這條記錄應該進行DN3')}, packetId=1], host=192.168.31.150, port=3307, statusSync=org.opencloudb.mysql.nio.MySQLConnection$StatusSync@48537945, writeQueue=0, modifiedSQLExecuted=true] frontend host:127.0.0.1/50644/test
再下來開始回滾所有數據結點上的更新操作。
02/03 00:36:10.305 DEBUG [$_NIOREACTOR-1-RW] (ServerQueryHandler.java:56) -ServerConnection [id=31, schema=TESTDB, host=127.0.0.1, user=test,txIsolation=3, autocommit=false, schema=TESTDB]rollback
02/03 00:36:10.305 DEBUG [$_NIOREACTOR-1-RW] (RollbackNodeHandler.java:71) -rollback job run for MySQLConnection [id=8, lastTime=1454430970269, user=root, schema=test, old shema=test, borrowed=true, fromSlaveDB=false, threadId=24, charset=utf8, txIsolation=3, autocommit=false, attachment=dn3{insert into t_demo_travel_record (id,context) values (14991499,'這條記錄應該進行DN3')}, respHandler=SingleNodeHandler [node=dn3{insert into t_demo_travel_record (id,context) values (14991499,'這條記錄應該進行DN3')}, packetId=1], host=192.168.31.150, port=3307, statusSync=org.opencloudb.mysql.nio.MySQLConnection$StatusSync@48537945, writeQueue=0, modifiedSQLExecuted=true]
02/03 00:36:10.305 DEBUG [$_NIOREACTOR-1-RW] (RollbackNodeHandler.java:71) -rollback job run for MySQLConnection [id=16, lastTime=1454430970269, user=root, schema=test, old shema=test, borrowed=true, fromSlaveDB=false, threadId=33, charset=utf8, txIsolation=3, autocommit=false, attachment=dn1{insert into t_demo_travel_record (id,context) values (5001,'這條記錄應該進行DN1')}, respHandler=SingleNodeHandler [node=dn1{insert into t_demo_travel_record (id,context) values (5001,'這條記錄應該進行DN1')}, packetId=1], host=192.168.31.187, port=3307, statusSync=null, writeQueue=0, modifiedSQLExecuted=true]
02/03 00:36:10.306 DEBUG [$_NIOREACTOR-1-RW] (RollbackNodeHandler.java:71) -rollback job run for MySQLConnection [id=28, lastTime=1454430970269, user=root, schema=test, old shema=test, borrowed=true, fromSlaveDB=false, threadId=30, charset=utf8, txIsolation=3, autocommit=false, attachment=dn2{insert into t_demo_travel_record (id,context) values (5999998,'這條記錄應該進行DN2')}, respHandler=SingleNodeHandler [node=dn2{insert into t_demo_travel_record (id,context) values (5999998,'這條記錄應該進行DN2')}, packetId=1], host=192.168.31.212, port=3307, statusSync=null, writeQueue=0, modifiedSQLExecuted=true]
02/03 00:36:10.312 DEBUG [$_NIOREACTOR-0-RW] (NonBlockingSession.java:361) -clear session resources org.opencloudb.server.NonBlockingSession@603ec61b
釋放數據庫鏈接
02/03 00:36:10.312 DEBUG [$_NIOREACTOR-0-RW] (NonBlockingSession.java:229) -release connection MySQLConnection [id=8, lastTime=1454430970269, user=root, schema=test, old shema=test, borrowed=true, fromSlaveDB=false, threadId=24, charset=utf8, txIsolation=3, autocommit=false, attachment=dn3{insert into t_demo_travel_record (id,context) values (14991499,'這條記錄應該進行DN3')}, respHandler=org.opencloudb.mysql.nio.handler.RollbackNodeHandler@394047fa, host=192.168.31.150, port=3307, statusSync=org.opencloudb.mysql.nio.MySQLConnection$StatusSync@48537945, writeQueue=0, modifiedSQLExecuted=true]
02/03 00:36:10.312 DEBUG [$_NIOREACTOR-0-RW] (NonBlockingSession.java:229) -release connection MySQLConnection [id=16, lastTime=1454430970269, user=root, schema=test, old shema=test, borrowed=true, fromSlaveDB=false, threadId=33, charset=utf8, txIsolation=3, autocommit=false, attachment=dn1{insert into t_demo_travel_record (id,context) values (5001,'這條記錄應該進行DN1')}, respHandler=org.opencloudb.mysql.nio.handler.RollbackNodeHandler@394047fa, host=192.168.31.187, port=3307, statusSync=null, writeQueue=0, modifiedSQLExecuted=true]
02/03 00:36:10.312 DEBUG [$_NIOREACTOR-0-RW] (NonBlockingSession.java:229) -release connection MySQLConnection [id=28, lastTime=1454430970269, user=root, schema=test, old shema=test, borrowed=true, fromSlaveDB=false, threadId=30, charset=utf8, txIsolation=3, autocommit=false, attachment=dn2{insert into t_demo_travel_record (id,context) values (5999998,'這條記錄應該進行DN2')}, respHandler=org.opencloudb.mysql.nio.handler.RollbackNodeHandler@394047fa, host=192.168.31.212, port=3307, statusSync=null, writeQueue=0, modifiedSQLExecuted=true]
02/03 00:36:10.313 DEBUG [$_NIOREACTOR-0-RW] (RollbackReleaseHandler.java:58) -autocomit is false,but no commit or rollback ,so mycat rollbacked backend conn MySQLConnection [id=8, lastTime=1454430970269, user=root, schema=test, old shema=test, borrowed=true, fromSlaveDB=false, threadId=24, charset=utf8, txIsolation=3, autocommit=false, attachment=null, respHandler=org.opencloudb.mysql.nio.handler.RollbackReleaseHandler@2b358b73, host=192.168.31.150, port=3307, statusSync=org.opencloudb.mysql.nio.MySQLConnection$StatusSync@48537945, writeQueue=0, modifiedSQLExecuted=true]
02/03 00:36:10.313 DEBUG [$_NIOREACTOR-0-RW] (PhysicalDatasource.java:403) -release channel MySQLConnection [id=8, lastTime=1454430970269, user=root, schema=test, old shema=test, borrowed=true, fromSlaveDB=false, threadId=24, charset=utf8, txIsolation=3, autocommit=false, attachment=null, respHandler=null, host=192.168.31.150, port=3307, statusSync=null, writeQueue=0, modifiedSQLExecuted=false]
02/03 00:36:10.313 DEBUG [$_NIOREACTOR-0-RW] (RollbackReleaseHandler.java:58) -autocomit is false,but no commit or rollback ,so mycat rollbacked backend conn MySQLConnection [id=16, lastTime=1454430970269, user=root, schema=test, old shema=test, borrowed=true, fromSlaveDB=false, threadId=33, charset=utf8, txIsolation=3, autocommit=false, attachment=null, respHandler=org.opencloudb.mysql.nio.handler.RollbackReleaseHandler@4856412e, host=192.168.31.187, port=3307, statusSync=null, writeQueue=0, modifiedSQLExecuted=true]
02/03 00:36:10.313 DEBUG [$_NIOREACTOR-0-RW] (PhysicalDatasource.java:403) -release channel MySQLConnection [id=16, lastTime=1454430970269, user=root, schema=test, old shema=test, borrowed=true, fromSlaveDB=false, threadId=33, charset=utf8, txIsolation=3, autocommit=false, attachment=null, respHandler=null, host=192.168.31.187, port=3307, statusSync=null, writeQueue=0, modifiedSQLExecuted=false]
02/03 00:36:10.313 DEBUG [$_NIOREACTOR-0-RW] (RollbackReleaseHandler.java:58) -autocomit is false,but no commit or rollback ,so mycat rollbacked backend conn MySQLConnection [id=28, lastTime=1454430970269, user=root, schema=test, old shema=test, borrowed=true, fromSlaveDB=false, threadId=30, charset=utf8, txIsolation=3, autocommit=false, attachment=null, respHandler=org.opencloudb.mysql.nio.handler.RollbackReleaseHandler@16d1581c, host=192.168.31.212, port=3307, statusSync=null, writeQueue=0, modifiedSQLExecuted=true]
02/03 00:36:10.313 DEBUG [$_NIOREACTOR-0-RW] (PhysicalDatasource.java:403) -release channel MySQLConnection [id=28, lastTime=1454430970269, user=root, schema=test, old shema=test, borrowed=true, fromSlaveDB=false, threadId=30, charset=utf8, txIsolation=3, autocommit=false, attachment=null, respHandler=null, host=192.168.31.212, port=3307, statusSync=null, writeQueue=0, modifiedSQLExecuted=false]
02
OK，通過2個場景驗證了MYCAT的事務一致性。
再補一句，大家可以通過MYSQL權威指南文檔了解到其實MYCAT實現一種弱XA的事務控制，怎么理解這個弱XA事務控制。
舉例有3個結點，MYCAT根據分片規則依次在不同物理庫中預執行，如果當中任何一個發現問題則回滾所有。
若預執行成功，3個結點分別進行commit操作時發生異常，則mycat無法回滾已提交的事務。當然，這種機率很小很小~~~
另外一個問題在於，如果發鎖升級導致單結點無法操作時，會對整體應用產生比較大的影響。
本篇完