I filed HBASE-4844 a while ago but never actually provided a patch. If you can comment on that jira with the exact use case that'd be helpful.
If you wanted to work on a patch that'd be cooler even :) -- Lars ________________________________ From: Jan Van Besien <[email protected]> To: [email protected] Sent: Monday, October 29, 2012 2:42 AM Subject: reading WAL log file from inside coprocessor I am implementing some functionality as a HBase coprocessor which relies on reading WALEdits from the HBase WAL. I have to requirements: - get notified whenever a new WALEdit is written to the WAL - have access to the actual WAL log file such that I can read from it whenever I want In a way, this is very similar to how HBase replication works. The first requirement is easy enough, using the WALObserver coprocessor interface. It is for the second requirement however, that I am asking this question. HBase replication uses the WALActionsListener interface to get notified when the log files are rolled. There doesn't seem to be a way to do that in a WALObserver (coprocessor interface) though. I thought of adding a WALActionsListener myself from inside the coprocessor code, but I would need to make sure that it is registered before the preLogRolled method is invoked for the first time. I also looked at HBASE-4132, but I believe this talks about the WALActionsListener and not the WALObserver. So.. any hints on how to do WAL reading (like replication) from inside a coprocessor? thanks, Jan
