Error during compact execution

[tleg...@infovista.com]

Hello,

I'm using the latest version of mapdb and sometimes I have the following exception (under windows):

INFO   | jvm 1    | 2013/09/24 07:32:57 | Caused by: java.lang.InternalError: could not rename file

INFO   | jvm 1    | 2013/09/24 07:32:57 | at org.mapdb.StoreDirect.compact(StoreDirect.java:670)

INFO   | jvm 1    | 2013/09/24 07:32:57 | at org.mapdb.StoreWAL.compact(StoreWAL.java:743)

INFO   | jvm 1    | 2013/09/24 07:32:57 | at org.mapdb.EngineWrapper.compact(EngineWrapper.java:111)

INFO   | jvm 1    | 2013/09/24 07:32:57 | at org.mapdb.EngineWrapper.compact(EngineWrapper.java:111)

INFO   | jvm 1    | 2013/09/24 07:32:57 | at org.mapdb.DB.compact(DB.java:1264)

After this exception, mapdb is unusable and I lost all datas:

INFO   | jvm 1    | 2013/09/24 07:34:17 | Caused by: java.lang.NullPointerException

INFO   | jvm 1    | 2013/09/24 07:34:17 | at org.mapdb.Volume$ByteBufferVol.internalByteBuffer(Volume.java:317)

INFO   | jvm 1    | 2013/09/24 07:34:17 | at org.mapdb.Volume$ByteBufferVol.getLong(Volume.java:356)

INFO   | jvm 1    | 2013/09/24 07:34:17 | at org.mapdb.StoreWAL.getLongStackPage(StoreWAL.java:575)

INFO   | jvm 1    | 2013/09/24 07:34:17 | at org.mapdb.StoreWAL.longStackTake(StoreWAL.java:599)

INFO   | jvm 1    | 2013/09/24 07:34:17 | at org.mapdb.StoreDirect.freePhysTake(StoreDirect.java:833)

INFO   | jvm 1    | 2013/09/24 07:34:17 | at org.mapdb.StoreDirect.physAllocate(StoreDirect.java:509)

INFO   | jvm 1    | 2013/09/24 07:34:17 | at org.mapdb.StoreWAL.put(StoreWAL.java:98)

INFO   | jvm 1    | 2013/09/24 07:34:17 | at org.mapdb.Caches$HashTable.put(Caches.java:186)

INFO   | jvm 1    | 2013/09/24 07:34:17 | at org.mapdb.EngineWrapper.put(EngineWrapper.java:45)

INFO   | jvm 1    | 2013/09/24 07:34:17 | at org.mapdb.SnapshotEngine.put(SnapshotEngine.java:44)

INFO   | jvm 1    | 2013/09/24 07:34:17 | at org.mapdb.BTreeMap.put2(BTreeMap.java:712)

INFO   | jvm 1    | 2013/09/24 07:34:17 | at org.mapdb.BTreeMap.put(BTreeMap.java:566) 

Questions are :

How to prevent from this issue?

How to restore original files?

How to perform a backup before the compact execution?

Note: Exception  in the code is here 

            if(!physFile.renameTo(physFile_))throw new InternalError("could not rename file");

Maybe it can be useful to add more information in InternalError like throw new InternalError("could not rename file " + physFile + " to" + physFile_)

Thanks.

[Jan Kotek]

Hi,

Windows file locking is broken. For memory mapped files it does not
release locks until system is restarted.

Solution is to disable use RandomAccessFiles (slower) or migrate to
linux.

I hope I will come with something better.

Jan

[Rajiv Kumar]

Hi Jan,

I am still facing this issue with mapdb 1.0.4/1.0.6. 

An exception occurred: java.lang.AssertionError: could not rename file

 at org.mapdb.StoreDirect.compact(StoreDirect.java:857)

 at org.mapdb.EngineWrapper.compact(EngineWrapper.java:130)

 at org.mapdb.DB.compact(DB.java:1607)

 at ...

Any idea on the timeline for resolution?

Regards

Rajiv