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我正在使用 C3P0 和 MS SQL JDBC 4 驱动程序在数据库消失时自动故障转移到新的数据库镜像。如果它首先连接到主数据库，则故障转移工作并无缝切换到镜像数据库。但是，如果在应用程序启动时主体 DB 已关闭，而镜像 DB 可以连接（使用 MSSQL Studio 测试），则应用程序无法启动并且无法连接到备份镜像。

这是连接网址：

jdbc:sqlserver://PRINCIPALDB;databaseName=app_space;port=99999;failoverPartner=MIRRORDB

我有c3p0.testConnectionOnCheckout并c3p0.preferredTestQuery设置，c3p0.acquireRetryAttempts但未设置（使用默认值 30）。

为什么当主体关闭时它最初不会连接到镜像数据库？我们需要这个，因为如果电源关闭或其他原因并且主体数据库关闭，并且应用服务器需要回收，那么故障转移将无济于事。

参考：

http://www.mchange.com/projects/c3p0/#configuring_recovery

使用数据库镜像 (JDBC)（MSDN 在其 URL 中使用非转义括号！） http://msdn.microsoft.com/en-US/library/aa342332(v=sql.90)

以下是该应用程序的一些日志。

<14>[APP]: INFO 20 Jul 2012 12:21:21,982 [main] net.sf.hibernate.connection.C3P0ConnectionProvider "C3P0 using driver: com.microsoft.sqlserver.jdbc.SQLServerDriver at URL: jdbc:sqlserver://PRINCIPAL;databaseName=APP_space;port=9999;failoverPartner=MIRRORDB"    
<14>[APP]: INFO 20 Jul 2012 12:21:21,982 [main] net.sf.hibernate.connection.C3P0ConnectionProvider "Connection properties: {user=USERNAME, password=PASSWORD}"    
<14>[APP]: INFO 20 Jul 2012 12:21:22,435 [main] net.sf.hibernate.transaction.TransactionFactoryFactory "Transaction strategy: net.sf.hibernate.transaction.JDBCTransactionFactory"
<14>[APP]: INFO 20 Jul 2012 12:21:22,450 [main] net.sf.hibernate.transaction.TransactionManagerLookupFactory "No TransactionManagerLookup configured (in JTA environment, use of process level read-write cache is not recommended)"    
<12>[APP]: WARN 20 Jul 2012 12:29:17,279 [main] net.sf.hibernate.cfg.SettingsFactory "Could not obtain connection metadata"    
<12>java.sql.SQLException: Connections could not be acquired from the underlying database! 
<12>    at com.mchange.v2.sql.SqlUtils.toSQLException(SqlUtils.java:106) 
<12>    at com.mchange.v2.c3p0.impl.C3P0PooledConnectionPool.checkoutPooledConnection(C3P0PooledConnectionPool.java:529) 
<12>    at com.mchange.v2.c3p0.impl.AbstractPoolBackedDataSource.getConnection(AbstractPoolBackedDataSource.java:128) 
<12>    at net.sf.hibernate.connection.C3P0ConnectionProvider.getConnection(C3P0ConnectionProvider.java:33) 
<12>    at net.sf.hibernate.cfg.SettingsFactory.buildSettings(SettingsFactory.java:84)

这是它有时会给出的一种不同类型的错误，带有死锁警告。

<14>[APP]: INFO 20 Jul 2012 18:05:43,049 [main] net.sf.hibernate.connection.C3P0ConnectionProvider "C3P0 using driver: com.microsoft.sqlserver.jdbc.SQLServerDriver at URL: jdbc:sqlserver://PRINCIPALDB:9999;databaseName=APP_space;failoverPartner=MIRRORDB:9999"
<14>[APP]: INFO 20 Jul 2012 18:05:43,049 [main] net.sf.hibernate.connection.C3P0ConnectionProvider "Connection properties: {user=USERNAME, password=PASSWORD}"
<14>[APP]: INFO 20 Jul 2012 18:05:43,190 [main] com.mchange.v2.log.MLog "MLog clients using log4j logging."
<14>[APP]: INFO 20 Jul 2012 18:05:43,518 [main] com.mchange.v2.c3p0.C3P0Registry "Initializing c3p0-0.9.1.2 [built 21-May-2007 15:04:56; debug? true; trace: 10]"
<14>[APP]: INFO 20 Jul 2012 18:05:43,612 [main] net.sf.hibernate.transaction.TransactionFactoryFactory "Transaction strategy: net.sf.hibernate.transaction.JDBCTransactionFactory"
<14>[APP]: INFO 20 Jul 2012 18:05:43,612 [main] net.sf.hibernate.transaction.TransactionManagerLookupFactory "No TransactionManagerLookup configured (in JTA environment, use of process level read-write cache is not recommended)"
<14>[APP]: INFO 20 Jul 2012 18:05:43,658 [main] com.mchange.v2.c3p0.impl.AbstractPoolBackedDataSource "Initializing c3p0 pool... com.mchange.v2.c3p0.PoolBackedDataSource@616301db [ connectionPoolDataSource -> com.mchange.v2.c3p0.WrapperConnectionPoolDataSource@d6ed198b [ acquireIncrement -> 5, acquireRetryAttempts -> 30, acquireRetryDelay -> 1000, autoCommitOnClose -> false, automaticTestTable -> null, breakAfterAcquireFailure -> false, checkoutTimeout -> 0, connectionCustomizerClassName -> null, connectionTesterClassName -> com.mchange.v2.c3p0.impl.DefaultConnectionTester, debugUnreturnedConnectionStackTraces -> false, factoryClassLocation -> null, forceIgnoreUnresolvedTransactions -> false, identityToken -> 1bqq23w8o1a6dec41cwe1cd|20e1bfee, idleConnectionTestPeriod -> 100, initialPoolSize -> 10, maxAdministrativeTaskTime -> 0, maxConnectionAge -> 0, maxI...
<14>...dleTime -> 3600, maxIdleTimeExcessConnections -> 0, maxPoolSize -> 150, maxStatements -> 1000, maxStatementsPerConnection -> 0, minPoolSize -> 10, nestedDataSource -> com.mchange.v2.c3p0.DriverManagerDataSource@2c0fb781 [ description -> null, driverClass -> null, factoryClassLocation -> null, identityToken -> 1bqq23w8o1a6dec41cwe1cd|20360e46, jdbcUrl -> jdbc:sqlserver://PRINCIPALDB:9999;databaseName=APP_space;failoverPartner=MIRRORDB:9999, properties -> {user=******, password=******} ], preferredTestQuery -> select * from CLUSTERSAFETY, propertyCycle -> 0, testConnectionOnCheckin -> false, testConnectionOnCheckout -> false, unreturnedConnectionTimeout -> 0, usesTraditionalReflectiveProxies -> false; userOverrides: {} ], dataSourceName -> null, factoryClassLocation -> null, identityToken -> 1bqq23w8o1a6dec41cwe1cd|6f3e49a8, numHelperThreads -> 3 ]"
<12>[APP]: WARN 20 Jul 2012 18:06:03,644 [Timer-0] com.mchange.v2.async.ThreadPoolAsynchronousRunner "com.mchange.v2.async.ThreadPoolAsynchronousRunner$DeadlockDetector@37f844f7 -- APPARENT DEADLOCK!!! Creating emergency threads for unassigned pending tasks!"
<12>[APP]: WARN 20 Jul 2012 18:06:03,644 [Timer-0] com.mchange.v2.async.ThreadPoolAsynchronousRunner "com.mchange.v2.async.ThreadPoolAsynchronousRunner$DeadlockDetector@37f844f7 -- APPARENT DEADLOCK!!! Complete Status: 
    Managed Threads: 3
    Active Threads: 3
    Active Tasks: 
        com.mchange.v2.resourcepool.BasicResourcePool$AcquireTask@52783859 (com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread-#0)
        com.mchange.v2.resourcepool.BasicResourcePool$AcquireTask@52bb855b (com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread-#1)
        com.mchange.v2.resourcepool.BasicResourcePool$AcquireTask@153043cc (com.mchange.v2.asyn...
<12>...c.ThreadPoolAsynchronousRunner$PoolThread-#2)
    Pending Tasks:

我使用此连接从文档中运行了一个测试程序：

jdbc:sqlserver://PRINCIPALDB:9999;databaseName=APP_space;portNumber=9999;failoverPartner=MIRRORDB:9999

它抛出了这个异常，就像它正在尝试与我指定的不同的端口一样！

Connection to principal server failed, trying the mirror server.
com.microsoft.sqlserver.jdbc.SQLServerException: The TCP/IP connection to the host MIRRORDB:9999, port 1433 has failed. Error: "null. Verify the connection properties. Make sure that an instance of SQL Server is running on the host and accepting TCP/IP connections at the port. Make sure that TCP connections to the port are not blocked by a firewall.".
    at com.microsoft.sqlserver.jdbc.SQLServerException.makeFromDriverError(SQLServerException.java:190)

重要的一点是它尝试连接到端口 1433 而不是我指定的端口，有很多不同的方式。

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2 回答 2

6

此处的 Sql Server JDBC 驱动程序文档有以下（令人困惑的）免责声明：

注意 驱动程序不支持将故障转移伙伴实例的服务器实例端口号指定为连接字符串中的 failoverPartner 属性的一部分。但是，支持在同一连接字符串中指定主体服务器实例的 serverName、instanceName 和 portNumber 属性以及故障转移伙伴实例的 failoverPartner 属性。

由此我建议添加： serverName=PRINCIPALDB;instanceName=MyInstance 属性，看看是否有效。

您提到故障转移处于活动状态。请注意，对于某些 Sql Server 镜像配置，故障转移不是自动的。您可能需要验证是否可以 使用 jdbc连接到MIRRORDB ：

jdbc:sqlserver://MIRRORDB;databaseName=app_space;port=9999;
于 2012-07-26T01:56:11.150 回答
6

我找到了答案！您必须将实例名称指定为主机名的一部分！例子：

jdbc:sqlserver://DEVSQLB\SQLB;databaseName=db_space;portNumber=99999;failoverPartner=BACKUPSQLA\SQLA

\SQLA实例名称在哪里！我不确定实例是什么，但我在 SQL Server 中看到过多次引用它。为了找出这些秘密信息，我（我的公司）不得不直接向 Microsoft 请求支持。

哦，忘了：

  • 您可以使用“server\instance_name”格式解决此问题，并确保浏览器服务正在运行并处于自动模式。
于 2012-09-11T21:57:00.137 回答