I am unable to maintain connections to my ClearDB instance. When my app first runs, I can make a request to it which accesses the DB just fine. After a minute or two, if I make the same request, I get a communications link failure. Here are the details of my application:
- Scala using Spray.io
- Slick for DB interaction
- ClearDB:ignite while testing this new application
- DataSource class: com.mchange.v2.c3p0.ComboPooledDataSource
If I run my application locally against my local MySQL instance, I can not reproduce the problem. If I change my DB URL to point to my ClearDB instance, I can reproduce this locally. Definitely seems like a ClearDB issue...
I contacted ClearDB support and they told me that they can't help me because they don't directly support Spray.io and that I should try to get help from Heroku directly. I've sent a help request to Heroku but not expecting much since I don't think Spray.io or Slick are directly supported there either. I've been scouring Stackoverflow as well with no luck so I'm posting this now.
Below is the full stack trace I get when I reproduce locally.
java.lang.x:com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure
The last packet successfully received from the server was 185,507 milliseconds ago. The last packet sent successfully to the server was 1 milliseconds ago.
com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure
The last packet successfully received from the server was 185,507 milliseconds ago. The last packet sent successfully to the server was 1 milliseconds ago.
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)[WARN] [01/26/2014 20:48:42.906] [LottoREST-akka.actor.default-dispatcher-4] [akka://LottoREST/user/lotto-service] Request HttpRequest(GET,http://localhost:8080/drawing,List(Cookie: JSESSIONID=4EFAE21258F8AF891C010DD14F9BC3F1, Accept-Language: en-US, en, Accept-Encoding: gzip, deflate, sdch, User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_9_1) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/32.0.1700.77 Safari/537.36, Cache-Control: max-age=0, Connection: keep-alive, Host: localhost:8080),Empty,HTTP/1.1) could not be handled normally
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:39)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:27)
at java.lang.reflect.Constructor.newInstance(Constructor.java:513)
at com.mysql.jdbc.Util.handleNewInstance(Util.java:411)
at com.mysql.jdbc.SQLError.createCommunicationsException(SQLError.java:1121)
at com.mysql.jdbc.MysqlIO.reuseAndReadPacket(MysqlIO.java:3720)
at com.mysql.jdbc.MysqlIO.reuseAndReadPacket(MysqlIO.java:3609)
at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:4160)
at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:2617)
at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:2778)
at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2825)
at com.mysql.jdbc.PreparedStatement.executeInternal(PreparedStatement.java:2156)
at com.mysql.jdbc.PreparedStatement.execute(PreparedStatement.java:1379)
at com.mchange.v2.c3p0.impl.NewProxyPreparedStatement.execute(NewProxyPreparedStatement.java:989)
at scala.slick.jdbc.StatementInvoker.results(StatementInvoker.scala:34)
at scala.slick.jdbc.StatementInvoker.elementsTo(StatementInvoker.scala:17)
at scala.slick.jdbc.Invoker$class.foreach(Invoker.scala:90)
at scala.slick.jdbc.StatementInvoker.foreach(StatementInvoker.scala:10)
at scala.slick.jdbc.Invoker$class.build(Invoker.scala:66)
at scala.slick.jdbc.StatementInvoker.build(StatementInvoker.scala:10)
at scala.slick.jdbc.Invoker$class.list(Invoker.scala:56)
at scala.slick.jdbc.StatementInvoker.list(StatementInvoker.scala:10)
at scala.slick.jdbc.UnitInvoker$class.list(Invoker.scala:150)
at scala.slick.driver.BasicInvokerComponent$QueryInvoker.list(BasicInvokerComponent.scala:19)
at com.megalottopools.model.DrawingComponent$Drawings$.findAllDrawings(Drawing.scala:28)
at com.megalottopools.model.Model.getDrawings(Model.scala:20)
at com.megalottopools.api.DrawingService$$anonfun$1.apply(DrawingService.scala:27)
at com.megalottopools.api.DrawingService$$anonfun$1.apply(DrawingService.scala:25)
at spray.routing.directives.BasicDirectives$$anonfun$mapRequestContext$1$$anonfun$apply$1.apply(BasicDirectives.scala:30)
at spray.routing.directives.BasicDirectives$$anonfun$mapRequestContext$1$$anonfun$apply$1.apply(BasicDirectives.scala:30)
at spray.routing.directives.BasicDirectives$$anon$3$$anonfun$happly$1.apply(BasicDirectives.scala:92)
at spray.routing.directives.BasicDirectives$$anon$3$$anonfun$happly$1.apply(BasicDirectives.scala:92)
at spray.routing.RouteConcatenation$RouteConcatenation$$anonfun$$tilde$1.apply(RouteConcatenation.scala:30)
at spray.routing.RouteConcatenation$RouteConcatenation$$anonfun$$tilde$1.apply(RouteConcatenation.scala:29)
at spray.routing.directives.BasicDirectives$$anonfun$mapRequestContext$1$$anonfun$apply$1.apply(BasicDirectives.scala:30)
at spray.routing.directives.BasicDirectives$$anonfun$mapRequestContext$1$$anonfun$apply$1.apply(BasicDirectives.scala:30)
at spray.routing.directives.BasicDirectives$$anon$3$$anonfun$happly$1.apply(BasicDirectives.scala:92)
at spray.routing.directives.BasicDirectives$$anon$3$$anonfun$happly$1.apply(BasicDirectives.scala:92)
at spray.routing.RouteConcatenation$RouteConcatenation$$anonfun$$tilde$1.apply(RouteConcatenation.scala:30)
at spray.routing.RouteConcatenation$RouteConcatenation$$anonfun$$tilde$1.apply(RouteConcatenation.scala:29)
at spray.routing.RouteConcatenation$RouteConcatenation$$anonfun$$tilde$1.apply(RouteConcatenation.scala:30)
at spray.routing.RouteConcatenation$RouteConcatenation$$anonfun$$tilde$1.apply(RouteConcatenation.scala:29)
at spray.routing.directives.BasicDirectives$$anonfun$mapRequestContext$1$$anonfun$apply$1.apply(BasicDirectives.scala:30)
at spray.routing.directives.BasicDirectives$$anonfun$mapRequestContext$1$$anonfun$apply$1.apply(BasicDirectives.scala:30)
at spray.routing.directives.ExecutionDirectives$$anonfun$handleExceptions$1$$anonfun$apply$4.apply(ExecutionDirectives.scala:35)
at spray.routing.directives.ExecutionDirectives$$anonfun$handleExceptions$1$$anonfun$apply$4.apply(ExecutionDirectives.scala:33)
at spray.routing.HttpServiceBase$class.runSealedRoute$1(HttpService.scala:36)
at spray.routing.HttpServiceBase$$anonfun$runRoute$1.applyOrElse(HttpService.scala:46)
at akka.actor.ActorCell.receiveMessage(ActorCell.scala:425)
at akka.actor.ActorCell.invoke(ActorCell.scala:386)
at akka.dispatch.Mailbox.processMailbox(Mailbox.scala:230)
at akka.dispatch.Mailbox.run(Mailbox.scala:212)
at akka.dispatch.ForkJoinExecutorConfigurator$MailboxExecutionTask.exec(AbstractDispatcher.scala:506)
at scala.concurrent.forkjoin.ForkJoinTask.doExec(ForkJoinTask.java:260)
at scala.concurrent.forkjoin.ForkJoinPool$WorkQueue.runTask(ForkJoinPool.java:1339)
at scala.concurrent.forkjoin.ForkJoinPool.runWorker(ForkJoinPool.java:1979)
at scala.concurrent.forkjoin.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:107)
Caused by: java.io.EOFException: Can not read response from server. Expected to read 4 bytes, read 0 bytes before connection was unexpectedly lost.
at com.mysql.jdbc.MysqlIO.readFully(MysqlIO.java:3166)
at com.mysql.jdbc.MysqlIO.reuseAndReadPacket(MysqlIO.java:3620)
... 51 more
