embedded mode thread-safe?

> I mean, once I have the Context object and opened a database, is it safe to > access (read/write) it from multiple threads?

> > I mean, once I have the Context object and opened a database, is it safe > to > > access (read/write) it from multiple threads? > > It depends on how you do it ;) If you call Command.execute() with the > same Context instance, you should be safe. >

On Sun, Oct 9, 2016 at 4:20 PM, Erdal Karaca <erdal.karaca.de at gmail.com> wrote: > Hi Christian, > I have setup a stress test to access the same DB in parallel. I have only > one call to the Context constructor and using that same Context instance for > all executions. > I still get this exception: > Caused by: 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:1108) > at org.basex.io.random.TableDiskAccess.lock(TableDiskAccess.java:139) > at org.basex.data.DiskData.startUpdate(DiskData.java:207) > at org.basex.query.up.ContextModifier.apply(ContextModifier.java:131) > at org.basex.query.up.Updates.apply(Updates.java:157) > at org.basex.query.QueryContext.iter(QueryContext.java:351) > at org.basex.query.QueryProcessor.value(QueryProcessor.java:101) > > I am accessing the returned elements (of the queries) via a Value.iter() > iterator. > The queries returns a sequence of 100 elements. > > Each access to the DB has its own subtree. > I.e. if "user 1" accesses the DB, then he only accesses the subtree assigned > to him. > > This is the DB tree structure: > MyDB > + users/usr1.xml/container > + users/usr2.xml/container > + ... > + users/usrN.xml/container > > Are iterators also thread-safe? > If not, what can I use instead? > > (Standalone unit test will follow.) > > 2016-10-06 20:07 GMT+02:00 Christian Grün <christian.gruen at gmail.com>: >> >> > I mean, once I have the Context object and opened a database, is it safe >> > to >> > access (read/write) it from multiple threads? >> >> It depends on how you do it ;) If you call Command.execute() with the >> same Context instance, you should be safe. > >

> You may need to call XQuery.execute, or call QueryProcessor.register > (and, finally, unregister) before retrieving results; but maybe you > should prepare an MCVE for us? > > > > On Sun, Oct 9, 2016 at 4:20 PM, Erdal Karaca <erdal.karaca.de at gmail.com> > wrote: > > Hi Christian, > > I have setup a stress test to access the same DB in parallel. I have only > > one call to the Context constructor and using that same Context instance > for > > all executions. > > I still get this exception: > > Caused by: 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:1108) > > at org.basex.io.random.TableDiskAccess.lock(TableDiskAccess.java:139) > > at org.basex.data.DiskData.startUpdate(DiskData.java:207) > > at org.basex.query.up.ContextModifier.apply(ContextModifier.java:131) > > at org.basex.query.up.Updates.apply(Updates.java:157) > > at org.basex.query.QueryContext.iter(QueryContext.java:351) > > at org.basex.query.QueryProcessor.value(QueryProcessor.java:101) > > > > I am accessing the returned elements (of the queries) via a Value.iter() > > iterator. > > The queries returns a sequence of 100 elements. > > > > Each access to the DB has its own subtree. > > I.e. if "user 1" accesses the DB, then he only accesses the subtree > assigned > > to him. > > > > This is the DB tree structure: > > MyDB > > + users/usr1.xml/container > > + users/usr2.xml/container > > + ... > > + users/usrN.xml/container > > > > Are iterators also thread-safe? > > If not, what can I use instead? > > > > (Standalone unit test will follow.) > > > > 2016-10-06 20:07 GMT+02:00 Christian Grün <christian.gruen at gmail.com>: > >> > >> > I mean, once I have the Context object and opened a database, is it > safe > >> > to > >> > access (read/write) it from multiple threads? > >> > >> It depends on how you do it ;) If you call Command.execute() with the > >> same Context instance, you should be safe. > > > > >

On Sun, Oct 9, 2016 at 4:44 PM, Erdal Karaca <erdal.karaca.de at gmail.com> wrote: > Hi Christian, > I have prepared a MCVE (see attachment). > Not sure how to use QueryProcess.register/unregister. > Is there an example? > XQuery.execute() does not return objects, just a string? > > 2016-10-09 16:36 GMT+02:00 Christian Grün <christian.gruen at gmail.com>: >> >> You may need to call XQuery.execute, or call QueryProcessor.register >> (and, finally, unregister) before retrieving results; but maybe you >> should prepare an MCVE for us? >> >> >> >> On Sun, Oct 9, 2016 at 4:20 PM, Erdal Karaca <erdal.karaca.de at gmail.com> >> wrote: >> > Hi Christian, >> > I have setup a stress test to access the same DB in parallel. I have >> > only >> > one call to the Context constructor and using that same Context instance >> > for >> > all executions. >> > I still get this exception: >> > Caused by: 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:1108) >> > at org.basex.io.random.TableDiskAccess.lock(TableDiskAccess.java:139) >> > at org.basex.data.DiskData.startUpdate(DiskData.java:207) >> > at org.basex.query.up.ContextModifier.apply(ContextModifier.java:131) >> > at org.basex.query.up.Updates.apply(Updates.java:157) >> > at org.basex.query.QueryContext.iter(QueryContext.java:351) >> > at org.basex.query.QueryProcessor.value(QueryProcessor.java:101) >> > >> > I am accessing the returned elements (of the queries) via a Value.iter() >> > iterator. >> > The queries returns a sequence of 100 elements. >> > >> > Each access to the DB has its own subtree. >> > I.e. if "user 1" accesses the DB, then he only accesses the subtree >> > assigned >> > to him. >> > >> > This is the DB tree structure: >> > MyDB >> > + users/usr1.xml/container >> > + users/usr2.xml/container >> > + ... >> > + users/usrN.xml/container >> > >> > Are iterators also thread-safe? >> > If not, what can I use instead? >> > >> > (Standalone unit test will follow.) >> > >> > 2016-10-06 20:07 GMT+02:00 Christian Grün <christian.gruen at gmail.com>: >> >> >> >> > I mean, once I have the Context object and opened a database, is it >> >> > safe >> >> > to >> >> > access (read/write) it from multiple threads? >> >> >> >> It depends on how you do it ;) If you call Command.execute() with the >> >> same Context instance, you should be safe. >> > >> > > >

> Would you mind rewriting it for Java 1.7? > > Thanks in advance, > Christian > > > On Sun, Oct 9, 2016 at 4:44 PM, Erdal Karaca <erdal.karaca.de at gmail.com> > wrote: > > Hi Christian, > > I have prepared a MCVE (see attachment). > > Not sure how to use QueryProcess.register/unregister. > > Is there an example? > > XQuery.execute() does not return objects, just a string? > > > > 2016-10-09 16:36 GMT+02:00 Christian Grün <christian.gruen at gmail.com>: > >> > >> You may need to call XQuery.execute, or call QueryProcessor.register > >> (and, finally, unregister) before retrieving results; but maybe you > >> should prepare an MCVE for us? > >> > >> > >> > >> On Sun, Oct 9, 2016 at 4:20 PM, Erdal Karaca <erdal.karaca.de at gmail.com > > > >> wrote: > >> > Hi Christian, > >> > I have setup a stress test to access the same DB in parallel. I have > >> > only > >> > one call to the Context constructor and using that same Context > instance > >> > for > >> > all executions. > >> > I still get this exception: > >> > Caused by: 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:1108) > >> > at org.basex.io.random.TableDiskAccess.lock(TableDiskAccess.java:139) > >> > at org.basex.data.DiskData.startUpdate(DiskData.java:207) > >> > at org.basex.query.up.ContextModifier.apply(ContextModifier.java:131) > >> > at org.basex.query.up.Updates.apply(Updates.java:157) > >> > at org.basex.query.QueryContext.iter(QueryContext.java:351) > >> > at org.basex.query.QueryProcessor.value(QueryProcessor.java:101) > >> > > >> > I am accessing the returned elements (of the queries) via a > Value.iter() > >> > iterator. > >> > The queries returns a sequence of 100 elements. > >> > > >> > Each access to the DB has its own subtree. > >> > I.e. if "user 1" accesses the DB, then he only accesses the subtree > >> > assigned > >> > to him. > >> > > >> > This is the DB tree structure: > >> > MyDB > >> > + users/usr1.xml/container > >> > + users/usr2.xml/container > >> > + ... > >> > + users/usrN.xml/container > >> > > >> > Are iterators also thread-safe? > >> > If not, what can I use instead? > >> > > >> > (Standalone unit test will follow.) > >> > > >> > 2016-10-06 20:07 GMT+02:00 Christian Grün <christian.gruen at gmail.com > >: > >> >> > >> >> > I mean, once I have the Context object and opened a database, is it > >> >> > safe > >> >> > to > >> >> > access (read/write) it from multiple threads? > >> >> > >> >> It depends on how you do it ;) If you call Command.execute() with the > >> >> same Context instance, you should be safe. > >> > > >> > > > > > >

On Sun, Oct 9, 2016 at 7:11 PM, Erdal Karaca <erdal.karaca.de at gmail.com> wrote: > I have re-written the test to use 1.7, and also adapted register/unregister, > but still I get this exception: > > Caused by: org.basex.core.BaseXException: Database 'stress-test' is being > updated, or update was not completed. > at org.basex.data.DiskData.startUpdate(DiskData.java:210) > at org.basex.query.up.ContextModifier.apply(ContextModifier.java:131) > > 2016-10-09 17:24 GMT+02:00 Christian Grün <christian.gruen at gmail.com>: >> >> Would you mind rewriting it for Java 1.7? >> >> Thanks in advance, >> Christian >> >> >> On Sun, Oct 9, 2016 at 4:44 PM, Erdal Karaca <erdal.karaca.de at gmail.com> >> wrote: >> > Hi Christian, >> > I have prepared a MCVE (see attachment). >> > Not sure how to use QueryProcess.register/unregister. >> > Is there an example? >> > XQuery.execute() does not return objects, just a string? >> > >> > 2016-10-09 16:36 GMT+02:00 Christian Grün <christian.gruen at gmail.com>: >> >> >> >> You may need to call XQuery.execute, or call QueryProcessor.register >> >> (and, finally, unregister) before retrieving results; but maybe you >> >> should prepare an MCVE for us? >> >> >> >> >> >> >> >> On Sun, Oct 9, 2016 at 4:20 PM, Erdal Karaca >> >> <erdal.karaca.de at gmail.com> >> >> wrote: >> >> > Hi Christian, >> >> > I have setup a stress test to access the same DB in parallel. I have >> >> > only >> >> > one call to the Context constructor and using that same Context >> >> > instance >> >> > for >> >> > all executions. >> >> > I still get this exception: >> >> > Caused by: 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:1108) >> >> > at org.basex.io.random.TableDiskAccess.lock(TableDiskAccess.java:139) >> >> > at org.basex.data.DiskData.startUpdate(DiskData.java:207) >> >> > at org.basex.query.up.ContextModifier.apply(ContextModifier.java:131) >> >> > at org.basex.query.up.Updates.apply(Updates.java:157) >> >> > at org.basex.query.QueryContext.iter(QueryContext.java:351) >> >> > at org.basex.query.QueryProcessor.value(QueryProcessor.java:101) >> >> > >> >> > I am accessing the returned elements (of the queries) via a >> >> > Value.iter() >> >> > iterator. >> >> > The queries returns a sequence of 100 elements. >> >> > >> >> > Each access to the DB has its own subtree. >> >> > I.e. if "user 1" accesses the DB, then he only accesses the subtree >> >> > assigned >> >> > to him. >> >> > >> >> > This is the DB tree structure: >> >> > MyDB >> >> > + users/usr1.xml/container >> >> > + users/usr2.xml/container >> >> > + ... >> >> > + users/usrN.xml/container >> >> > >> >> > Are iterators also thread-safe? >> >> > If not, what can I use instead? >> >> > >> >> > (Standalone unit test will follow.) >> >> > >> >> > 2016-10-06 20:07 GMT+02:00 Christian Grün >> >> > <christian.gruen at gmail.com>: >> >> >> >> >> >> > I mean, once I have the Context object and opened a database, is >> >> >> > it >> >> >> > safe >> >> >> > to >> >> >> > access (read/write) it from multiple threads? >> >> >> >> >> >> It depends on how you do it ;) If you call Command.execute() with >> >> >> the >> >> >> same Context instance, you should be safe. >> >> > >> >> > >> > >> > > >