使用druid数据源，由于网络问题导致oracle SocketInputStream.socketRead0堵塞解决办法

线上Oracle数据库网络非常不稳定，不时发生连接闪断，发现一个线程一直堵塞，日志没有错误。dump出线程信息后如下：

pool-4-thread-50" prio=10 tid=0x00007f92f5251000 nid=0x26e1 runnable [0x00007f929a1df000]

   java.lang.Thread.State: RUNNABLE
at java.net.SocketInputStream.socketRead0(Native Method)
at java.net.SocketInputStream.read(SocketInputStream.java:152)
at java.net.SocketInputStream.read(SocketInputStream.java:122)
at oracle.net.ns.Packet.receive(Packet.java:282)
at oracle.net.ns.DataPacket.receive(DataPacket.java:103)
at oracle.net.ns.NetInputStream.getNextPacket(NetInputStream.java:230)
at oracle.net.ns.NetInputStream.read(NetInputStream.java:175)
at oracle.net.ns.NetInputStream.read(NetInputStream.java:100)
at oracle.net.ns.NetInputStream.read(NetInputStream.java:85)
at oracle.jdbc.driver.T4CSocketInputStreamWrapper.readNextPacket(T4CSocketInputStreamWrapper.java:122)
at oracle.jdbc.driver.T4CSocketInputStreamWrapper.read(T4CSocketInputStreamWrapper.java:78)
at oracle.jdbc.driver.T4CMAREngine.unmarshalUB1(T4CMAREngine.java:1179)
at oracle.jdbc.driver.T4CMAREngine.unmarshalSB1(T4CMAREngine.java:1155)
at oracle.jdbc.driver.T4CTTIfun.receive(T4CTTIfun.java:279)
at oracle.jdbc.driver.T4CTTIfun.doRPC(T4CTTIfun.java:186)
at oracle.jdbc.driver.T4C8Oall.doOALL(T4C8Oall.java:521)
at oracle.jdbc.driver.T4CStatement.doOall8(T4CStatement.java:194)
at oracle.jdbc.driver.T4CStatement.executeForDescribe(T4CStatement.java:853)
at oracle.jdbc.driver.OracleStatement.executeMaybeDescribe(OracleStatement.java:1145)
at oracle.jdbc.driver.OracleStatement.doExecuteWithTimeout(OracleStatement.java:1259)
at oracle.jdbc.driver.OracleStatement.executeQuery(OracleStatement.java:1469)
- locked <0x000000074abc5ae8> (a oracle.jdbc.driver.T4CConnection)
at oracle.jdbc.driver.OracleStatementWrapper.executeQuery(OracleStatementWrapper.java:389)
at com.alibaba.druid.pool.vendor.OracleValidConnectionChecker.isValidConnection(OracleValidConnectionChecker.java:84)
at com.alibaba.druid.pool.DruidAbstractDataSource.testConnectionInternal(DruidAbstractDataSource.java:1358)
at com.alibaba.druid.pool.DruidDataSource.getConnectionDirect(DruidDataSource.java:1260)

由于网络不稳定，每次拿连接的时候先测试连接的可用性，但是发生了socket 读堵塞。阻塞了线程的运行。是查询超时没有设置，我立即查看DruidDataSource配置是否有查询超时配置。发现如下三个配置

datasource.setValidationQueryTimeout(queryTimeout);
datasource.setQueryTimeout(queryTimeout);
datasource.setTransactionQueryTimeout(queryTimeout);

重新添加配置后重启，继续观察。隔几天再次发现还是堵塞。判断这些查询超时的配置不能设置到Socket的读超时设置中。查看资料发现需要配置如下属性

datasource.connectionProperties=oracle.jdbc.ReadTimeout=10000;oracle.net.CONNECT_TIMEOUT=10000

参考资料：https://www.jianshu.com/p/6d19e0d7f81c
https://www.cubrid.org/blog/understanding-jdbc-internals-and-timeout-configuration
资料里面有详细的解读。