Thanks for the feedback. there is room for improvement here for sure. Feel free to open jira issues to capture your experiences and contribute updates.
The lease locker needs a jdbc connection and emerged from the jdbc store so it needs a little more work to be fully separated. For one, the statements should be externally configurable and the dependency on a persistence adapter made optional. Ie: it should be possible to use it as broker lock rather than a store lock. I opened https://issues.apache.org/jira/browse/AMQ-4365 to track this. The optional org.apache.activemq.broker.Locker#configure needs a variant that will set the brokerService so that the ioexception handler and identity are available. Maybe just being brokerServiceAware is sufficient. btw: the xml schema is auto generated from the interfaces by xbean so it shows up as an option, independent of the implementation dependencies. On 8 March 2013 05:13, Paul Gale <paul.n.g...@gmail.com> wrote: > Hi, > > Using: ActiveMQ 5.8.0 on RHEL 6.0 > > The documentation states that storage lockers are pluggable with regards to > persistence adapters. Taking it at its word I tried to combine the > lease-database-locker with the KahaDB persistence adapter. Fail. After > looking at the code for the lease-database-locker it's no wonder: it's > expecting a JDBCPersistenceAdapter as a parent. Doh. Not that pluggable > after all. > > So I have to come up with my own version of a lease-database-locker that > _will_ work with the KahaDBPersistenceAdapter. Why? Per the doc: NFSv4 is > required for failover to work reliably using KahaDB when using its default > storage locker. I'm restricted to using NFSv3 which is not going to work > with the default shared-file-locker. Therefore I need a hybrid approach: > Kaha for storage and a database for locking. Sounds easy enough, all I need > is a custom database lease locker. Or so I thought. However, after looking > it over it doesn't appear to be quite so straightforward given the somewhat > bazaar separation of responsibilities that exist given the actual > implementations of the respective persistence adapters and lockers. I've > made a few attempts at such a locker (the details of which I won't get into > here) but none of them worked. > > Has anyone out there written a custom locker like this? If so, any guidance > would be much appreciated. > > If no one has attempted this then I'll start getting into the specifics of > my attempts so far and others can chime in at that point. > > Incidentally the XML schema indicates that the lease-database-locker tag is > a legitimate child tag for kahaDB. Why is that given that they cannot work > together out of the box? > > Thanks, > Paul > -- http://redhat.com http://blog.garytully.com
