Hi Narashimham,
If you haven’t see it yet, the Wiki page on transactions will give you some insight how locking works in BaseX [1]. Do all of your modules run in the same JVM, and have you ensured that all operations use the same context? If yes, feel free to send us your sample code that demonstrates the problem.
Best, Christian
[1] http://docs.basex.org/wiki/Transaction_Management ___________________________
2013/10/20 EV Narasimham evnarasimham@gmail.com:
Hi, I have 3 application modules. One module, creates the xml database, the second/third module execute queries on the database (no updates are being performed on the database).
When the second and the third module try accessing the database, oncemodule is able to query the database while the other module ends up with the below exception.
org.basex.core.BaseXException: Improper use? Potential bug? Your feedback is welcome: Contact: basex-talk@mailman.uni-konstanz.de Version: BaseX 7.8 beta Java: Oracle Corporation, 1.7.0_25 OS: Linux, amd64 Stack Trace: java.nio.channels.OverlappingFileLockException at sun.nio.ch.SharedFileLockTable.checkList(FileLockTable.java:255) at sun.nio.ch.SharedFileLockTable.add(FileLockTable.java:152) at sun.nio.ch.FileChannelImpl.tryLock(FileChannelImpl.java:1017) at org.basex.io.random.TableDiskAccess.lck(TableDiskAccess.java:183) at org.basex.io.random.TableDiskAccess.sharedLock(TableDiskAccess.java:170) at org.basex.io.random.TableDiskAccess.<init>(TableDiskAccess.java:83) at org.basex.data.DiskData.init(DiskData.java:122) at org.basex.data.DiskData.<init>(DiskData.java:92) at org.basex.core.cmd.Open.open(Open.java:68) at org.basex.core.cmd.Open.run(Open.java:35) at org.basex.core.Command.run(Command.java:344) at org.basex.core.Command.exec(Command.java:320) at org.basex.core.Command.execute(Command.java:77) at org.basex.core.Command.execute(Command.java:89)
Below are the options being set: context.globalopts.set(GlobalOptions.GLOBALLOCK, false) ; context.globalopts.set(GlobalOptions.PARALLEL, 1) ; //After referring to https://github.com/BaseXdb/basex/issues/574
When the same exercise is being undertaken on a windows machine, the above behavior does not occur.
Regards Narasimham
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