SEVERE: java.lang.AssertionError: unknown trans log instruction '0' at log offset: 16

[cszamudio]

I started seeing this AssertionError on MapDB version 1.0.7.

May 07, 2015 11:47:01 AM org.mapdb.StoreWAL replayLogFile
SEVERE: java.lang.AssertionError: unknown trans log instruction '0' at log offset: 16

I noticed that this issue was resolved in 1.0.5, but I think it might still be an issue.

I am using a very simple map created as:

db = DBMaker.newFileDB(dbFile)
                .make();

The map has over 2 million simple entries <Integer, Date>
with no concurrent access to the map. The error occurs on the db.commit() statement.

May 07, 2015 11:47:01 AM org.mapdb.StoreWAL replayLogFile
SEVERE: java.lang.AssertionError: unknown trans log instruction '0' at log offset: 16
     at org.mapdb.StoreWAL.replayLogFile(StoreWAL.java:827)
     at org.mapdb.StoreWAL.commit(StoreWAL.java:606)
     at org.mapdb.EngineWrapper.commit(EngineWrapper.java:94)
     at org.mapdb.DB.commit(DB.java:1605)

It's intermittent. The MapDb file is still readable and I can subsequently add and remove to it even after the error is thrown by closing and then re-opening.

[jankotek]

It is happening at offset 16, where no data are yet added. My guess is that there is empty commit or file was not synced yet. Will look into this.

[zepernick]

I have been struggling with this issue intermittently as well. I have multiple threads working off the cache which I think might be part of the problem, but I am not sure. It usually goes away if I synchronize the method that is accessing the cache, but this really hinders my performance. I have tried putting synchronize blocks inside the method instead, but I have not been able to get that right because it still pops up every now and then.

[jankotek]

Can not replicate, please use 2.0 branch.