Question

我从java / scala worker连接到我的mysql服务器时遇到了一些麻烦。

这是我得到的堆栈跟踪：

The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server.
    at sun.reflect.GeneratedConstructorAccessor25.newInstance(Unknown Source) ~[na:na]
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45) ~[na:1.6.0_27]
    at java.lang.reflect.Constructor.newInstance(Constructor.java:532) ~[na:1.6.0_27]
    at com.mysql.jdbc.Util.handleNewInstance(Util.java:411) ~[indexer-worker-1.0-SNAPSHOT-jar-with-dependencies.jar:na]
    at com.mysql.jdbc.SQLError.createCommunicationsException(SQLError.java:1121) ~[indexer-worker-1.0-SNAPSHOT-jar-with-dependencies.jar:na]
    at com.mysql.jdbc.MysqlIO.<init>(MysqlIO.java:355) ~[indexer-worker-1.0-SNAPSHOT-jar-with-dependencies.jar:na]
    at com.mysql.jdbc.ConnectionImpl.coreConnect(ConnectionImpl.java:2479) ~[indexer-worker-1.0-SNAPSHOT-jar-with-dependencies.jar:na]
    at com.mysql.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:2516) ~[indexer-worker-1.0-SNAPSHOT-jar-with-dependencies.jar:na]
    at com.mysql.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:2301) ~[indexer-worker-1.0-SNAPSHOT-jar-with-dependencies.jar:na]
    at com.mysql.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:834) ~[indexer-worker-1.0-SNAPSHOT-jar-with-dependencies.jar:na]
    at com.mysql.jdbc.JDBC4Connection.<init>(JDBC4Connection.java:47) ~[indexer-worker-1.0-SNAPSHOT-jar-with-dependencies.jar:na]
    at sun.reflect.GeneratedConstructorAccessor10.newInstance(Unknown Source) ~[na:na]
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45) ~[na:1.6.0_27]
    at java.lang.reflect.Constructor.newInstance(Constructor.java:532) ~[na:1.6.0_27]
    at com.mysql.jdbc.Util.handleNewInstance(Util.java:411) ~[indexer-worker-1.0-SNAPSHOT-jar-with-dependencies.jar:na]
    at com.mysql.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:416) ~[indexer-worker-1.0-SNAPSHOT-jar-with-dependencies.jar:na]
    at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:317) ~[indexer-worker-1.0-SNAPSHOT-jar-with-dependencies.jar:na]
    at java.sql.DriverManager.getConnection(DriverManager.java:620) ~[na:1.6.0_27]
    at java.sql.DriverManager.getConnection(DriverManager.java:200) ~[na:1.6.0_27]
    at listen$IndexTransactionWorkerImpl.run(listen.scala:38) [indexer-worker-1.0-SNAPSHOT-jar-with-dependencies.jar:na]
    at net.greghaines.jesque.worker.WorkerImpl.execute(WorkerImpl.java:630) [indexer-worker-1.0-SNAPSHOT-jar-with-dependencies.jar:na]
    at net.greghaines.jesque.worker.WorkerImpl.process(WorkerImpl.java:600) [indexer-worker-1.0-SNAPSHOT-jar-with-dependencies.jar:na]
    at net.greghaines.jesque.worker.WorkerImpl.poll(WorkerImpl.java:491) [indexer-worker-1.0-SNAPSHOT-jar-with-dependencies.jar:na]
    at net.greghaines.jesque.worker.WorkerImpl.run(WorkerImpl.java:230) [indexer-worker-1.0-SNAPSHOT-jar-with-dependencies.jar:na]
    at java.lang.Thread.run(Thread.java:679) [na:1.6.0_27]
Caused by: java.net.UnknownHostException: mysql-vip
    at java.net.InetAddress.getAllByName0(InetAddress.java:1229) ~[na:1.6.0_27]
    at java.net.InetAddress.getAllByName(InetAddress.java:1156) ~[na:1.6.0_27]
    at java.net.InetAddress.getAllByName(InetAddress.java:1092) ~[na:1.6.0_27]
    at com.mysql.jdbc.StandardSocketFactory.connect(StandardSocketFactory.java:249) ~[indexer-worker-1.0-SNAPSHOT-jar-with-dependencies.jar:na]
    at com.mysql.jdbc.MysqlIO.<init>(MysqlIO.java:305) ~[indexer-worker-1.0-SNAPSHOT-jar-with-dependencies.jar:na]
    ... 29 common frames omitted

直到某一点工作正常，工人无法解析主机。如果我重新启动工作程序，它将再次运行。

重要的是：我能够从机器上ping主机！

我尝试使用ipv4代替Djava.net.preferIPv4Stack=true，但我在ipv4堆栈中遇到了同样的错误。

到目前为止我没有任何线索！谢谢你的帮助！

Answer 1

这可能有多种原因如果您没有正确管理连接池，可能会发生这种情况。从某种意义上说，如果你自己维护一个连接池（或者说使用apache dhcp或其他东西），那么要么你有太多的连接打开，一切都被阻止或者没有很好地管理资源。

另一个原因可能是:(它发生在我们一个多月后）。当一次执行太多长查询时。我们在程序方面做了一些优化，事情开始起作用（通过禁用读锁定）。

试图连接到tomcat6上的mysql服务器：java.net.UnknownHostException

1 个答案: