Christopher, On 8/17/15, 5:59 PM, "Christopher Schultz" <ch...@christopherschultz.net> wrote:
>Philip, > >On 8/17/15 12:27 PM, Wernersbach, Philip wrote: >> We are developing a JDBC driver that implements the JDBC API. Our >> driver works and we can use it in servlets, but Tomcat doesn¹t seem >> to know that the connections in the thread pool can be reused, so >> after all of the connection slots in the thread pool are used, the >> servlets hang trying to get a connection. > >If you set maxTotal="1", you get a timeout when you try to fetch a >second connection? Yes. To test this I modified the code and got two connections consecutively, and it hung on getting the second connection. >Are you sure the servlet called Connection.close()? That seemed to be the problem. I audited our code and found a corner case where Connection.close() was not called. I fixed it, and all seems to work as it should. > >What does the stack trace of the request-processing thread look like >when it's hung up? It hung at DataSource.getConnection() with this stack trace: Unsafe.park(boolean, long) line: not available [native method] LockSupport.park(Object) line: 175 AbstractQueuedSynchronizer$ConditionObject.await() line: 2039 LinkedBlockingDeque<E>.takeFirst() line: 582 GenericObjectPool<T>.borrowObject(long) line: 439 GenericObjectPool<T>.borrowObject() line: 360 PoolingDataSource<C>.getConnection() line: 133 BasicDataSource.getConnection() line: 1532 IngDb.getDbConnection() line: 42 > >> What API does the Tomcat DataSource Connection thread pool use to >> know a connection can be reused? This is an API question, but our >> specific version of Tomcat is 8.0.24. > >Are you using DBCP2 (the default) or Tomcat's jdbc-pool? DBCP2 > >Do you mean to check to see if a connection is valid for re-use? Our servlet code doesn¹t need to check if a connection is valid for re-use, we just need Tomcat to know that our connections are always valid for re-use in the pool (the database connection is automatically kept alive until it is explicitly closed). > >I think the answer for /both/ is that they use this call: > > Connection.isValid(int timeout) > >What version of JDBC are you implementing? It seems that Java 6 is when >the Connection.isValid method was added. JDBC 4.2, which does have Connection.isValid(), we¹ve implemented it. > >Or did you mean to check to see if a connection can be re-used *at all* >-- meaning, can the connection even really be used in a pool? > >What does your <Resource> element look like in context.xml? > >-chris I¹m assuming Tomcat will automatically take care of pooling even though we¹re calling Connection.close()? Our close() implementation explicitly closes the database connection, in such a way that it can¹t be reused. Thanks, Philip Wernersbach Software Engineer Ingram Content --------------------------------------------------------------------- To unsubscribe, e-mail: dev-unsubscr...@tomcat.apache.org For additional commands, e-mail: dev-h...@tomcat.apache.org
