MS SQL JDBC驱动程序在Tomcat 9上使用JNDI Hikari创建内存泄漏

Question

 <Resource name="jdbc/mydb" auth="Container"
      factory="com.zaxxer.hikari.HikariJNDIFactory"
      type="javax.sql.DataSource"
      minimumIdle="5" 
      maximumPoolSize="20"
      connectionTimeout="300000"
      dataSourceClassName="com.microsoft.sqlserver.jdbc.SQLServerDataSource"
      dataSource.url="jdbc:sqlserver://server:1433;databaseName=mydb"      
      dataSource.user="fantomas"
      dataSource.password="somepassword" 
      closeMethod="close"
      />

09-May-2018 10:15:16.971 WARNING [main] org.apache.catalina.loader.WebappClassLoaderBase.clearReferencesThreads The web application [host-manager] appears to have started a thread named [mssql-jdbc-TimeoutTimer-1] but has failed to stop it. This is very likely to create a memory leak. Stack trace of thread:
 sun.misc.Unsafe.park(Native Method)
 java.util.concurrent.locks.LockSupport.parkNanos(LockSupport.java:215)
 java.util.concurrent.SynchronousQueue$TransferStack.awaitFulfill(SynchronousQueue.java:460)
 java.util.concurrent.SynchronousQueue$TransferStack.transfer(SynchronousQueue.java:362)
 java.util.concurrent.SynchronousQueue.poll(SynchronousQueue.java:941)
 java.util.concurrent.ThreadPoolExecutor.getTask(ThreadPoolExecutor.java:1073)
 java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1134)
 java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
 java.lang.Thread.run(Thread.java:748)

Tomcat安装的。/lib中的UPDATE-1自定义库有：

ms-sql-6.4.0.jre8.jar 
slf4j-api-1.7.25.jar 
HikariCP-2.7.8.jar 

更新-2 Hikari 3.1.0和Tomcat 9.0.8也有同样的问题

Answer 1

有问题的线程（mssql-jdbc-TimeoutTimer）属于MSSQL驱动程序。当您使用HikariCP时，它就会出现，而不是Tomcat JDBC时，因为为了可靠性，HikariCP适当地使用了JDBC超时API。

这是MSSQL驱动程序的一个已知问题，请在此处搜索'mssql-jdbc-timeouttimer'。

似乎计时器是由hikaricp调用connection.isvalid()的MSSQL驱动程序实现启动的。因此，您可以通过设置ConnectionTestQuery来避免这个问题，这将禁用isvalid()的使用。