Home | About | Sematext search-lucene.com search-hadoop.com
 Search Hadoop and all its subprojects:

Switch to Threaded View
HBase >> mail # user >> reading WAL log file from inside coprocessor

Copy link to this message
Re: reading WAL log file from inside coprocessor
On 10/29/2012 04:34 PM, lars hofhansl wrote:
> 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 :)

Interesting thanks, I'll look into it.

The ticket seems to confirm that registering a WALActionListener from
inside a coprocessor is not going to work. Something I discovered today
as well.

With a completely different approach, I did manage to get something
working by constructing the path to the HLog files myself (in the
coprocessor) and reading them from there. So I am not notified about the
HLog files being rolled etc, I simply poll the directory on HDFS for
available files. It's a bit an ugly solution, and (apart from additional
delays) maybe there are even issues with it that I did not think of yet?

Anyway, I would like the HBASE-4844 approach a lot better for sure.