java.nio.channels.ClosedChannelException and unrecoverable error

[Neil Avery]

Hi All,

[Version 1.0.4]

We are experiencing the following Error when using mapDB is a fairly simple manner . The DB is created using:

val db: DB = DBMaker.newFileDB(new java.io.File(parentDir, "DbEvents")).closeOnJvmShutdown().cacheDisable().cacheSize(1024).transactionDisable().deleteFilesAfterClose().make()

Then we create treeMaps for user sessions - where data is pumped into their relevant instance...

db.createTreeMap(requestId).makeOrGet[java.lang.Long, ReplayEvent]

With a bit of thrashing about we experience the following Exception which the system cannot recover from. The Db is never closed - but there will be multiple streams going into successive trees concurrently.

Any clues?

Regards,

Na.

java.io.IOError: java.nio.channels.ClosedChannelException

at org.mapdb.Volume$FileChannelVol.getLong(Volume.java:837)

at org.mapdb.StoreDirect.get2(StoreDirect.java:440)

at org.mapdb.StoreDirect.get(StoreDirect.java:428)

at org.mapdb.EngineWrapper.get(EngineWrapper.java:58)

at org.mapdb.BTreeMap.get(BTreeMap.java:595)

at org.mapdb.BTreeMap.get(BTreeMap.java:589)

at org.mapdb.DB.catGet(DB.java:100)

at org.mapdb.DB$BTreeMapMaker.makeOrGet(DB.java:650)

at com.lll.play.replay.PerRequestSessionDb.<init>(PerRequestSessionDb.scala:23)

at org.eclipse.jetty.websocket.WebSocketConnectionRFC6455$WSFrameHandler.onFrame(WebSocketConnectionRFC6455.java:835)

at org.eclipse.jetty.websocket.WebSocketParserRFC6455.parseNext(WebSocketParserRFC6455.java:349)

at org.eclipse.jetty.websocket.WebSocketConnectionRFC6455.handle(WebSocketConnectionRFC6455.java:225)

at org.eclipse.jetty.io.nio.SelectChannelEndPoint.handle(SelectChannelEndPoint.java:628)

at org.eclipse.jetty.io.nio.SelectChannelEndPoint$1.run(SelectChannelEndPoint.java:52)

at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob(QueuedThreadPool.java:608)

at org.eclipse.jetty.util.thread.QueuedThreadPool$3.run(QueuedThreadPool.java:543)

at java.lang.Thread.run(Thread.java:744)

Caused by: java.nio.channels.ClosedChannelException

at sun.nio.ch.FileChannelImpl.ensureOpen(FileChannelImpl.java:99)

at sun.nio.ch.FileChannelImpl.read(FileChannelImpl.java:678)

at org.mapdb.Volume$FileChannelVol.readFully(Volume.java:806)

at org.mapdb.Volume$FileChannelVol.getLong(Volume.java:834)

... 29 more

[Jan Kotek]

Hi,

 

ClosedChannelException happens if one of the threads is interrupted while doing IO. The FileChannel gets closed on interruption and all future IOs will throw CCE. There is workaround to use memory-mapped files (mmapFileEnable()), but they only work on 64bit systems.

 

So either enable mmap or investigate what is interrupting your threads.

 

Jan

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[Neil Avery]

Brilliant - thank you!