Hi Michel,

thanks for providing us with all the details.

I'm glad to hear the problem seems to be fixed in the 7.8 snapshot. You can safely switch to this version; the official 7.8 release is planned for next week (in alignment with the XMLPrague conference).

Hope this helps, Christian

On Wed, Feb 5, 2014 at 6:15 PM, Michel Banguerski banguerski@gmail.com wrote:

Greetings,

I am currently using BaseX 7.7.2 on windows 7.

Periodically I get a corrupted database which topically manifests itself by the following message:

Improper use? Potential bug? Your feedback is welcome: Contact: basex-talk@mailman.uni-konstanz.de Version: BaseX 7.7.2 Java: Oracle Corporation, 1.7.0_45 OS: Windows 7, x86 Stack Trace: java.lang.ArrayIndexOutOfBoundsException: 33 at org.basex.io.random.TableDiskAccess.flush(TableDiskAccess.java:124) at org.basex.data.DiskData.finishUpdate(DiskData.java:212) at org.basex.core.cmd.Add.run(Add.java:109) at org.basex.core.Command.run(Command.java:345) at org.basex.core.Command.exec(Command.java:321) at org.basex.core.Command.execute(Command.java:78) at org.basex.server.LocalSession.execute(LocalSession.java:122) at org.basex.server.Session.execute(Session.java:37) at org.basex.core.Main.execute(Main.java:146) at org.basex.core.Main.execute(Main.java:130) at org.basex.core.Main.console(Main.java:90) at org.basex.BaseX.<init>(BaseX.java:168) at org.basex.BaseX.main(BaseX.java:38)

Once the database is corrupted there is no means to get the information back. In order to restore a backup I have to manually shutdown running java processes to remove the locks.

I was able to narrow the circumstances of the corruption event to the following.

• The corruption occurs when adding a resource to the database
• The added resource needs to be big enough (one additional characher or xml

node makes the difference)

• The database has to be in a certain state at the moment of the resource

addition for the corruption to happen: the same resource added at a different time will note cause corruption

• The database could leave the 'pre-corruption' state if some activity

happens

I was able to capture a database in 'pre-corruption' state in a backup, the database has no resources (all removed previously) and the backup is 44Kb I also have an couple of XML files that cause corruption of this database when added both are 2kb.

I mostly experience the corruption when using db:add() or db:replace() functions in xqm files but in the example I managed to capture the corruption happens when issuing the add command in CLI as well.

I can provide the backup and XML files but I suppose that sending them to the list as attachments would not be welcomed.

I performed the same test with the same result on Linux:

• restaure the 'pre-corrupted' backup
• open the database
• add the XML file

Finally I performed the same tests with BaseX78-20140203.150949 and no corruption happened.

I'm seeking the most stable configuration for my application and therefore I would like to have Your opinion: Should I seek a workaround in BaseX 7.7.2 to avoid corruption or should I go with 7.8 in spite it being in beta stage?

TIA Best regards Michel

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