Speaking from experience of trying to work with the WAL to implement
data-center replication: I would not recommend trying to use the WALs
yourself. This is not a fun part of the code to try to reason about and
it's not designed to be consumed by users. At all.
I would push you to look at Fluo (http://fluo.io).
Using the data-center replication feature
(http://accumulo.apache.org/1.7/accumulo_user_manual.html#_replication)
as a notification bus is possible and would hopefully be a bit more
stable than trying to write it all yourself.
Parise, Jonathan wrote:
Hi,
I’m working on a system where generally changes to Accumulo will come
through that system. However, in some cases, another system may change
data without my system being aware of it.
What I would like to do is somehow listen for changes to the tables my
system cares about. I know there is a write ahead log that I could
potentially listen to for changes, but I don’t know how to use it. I
looked around for some documentation about it, and I don’t see much. I
get the impression that it isn’t really intended for this type of use case.
Does anyone have any suggestions on how to watch a table for changes and
then determine if those changes were made by a different system.
Is there some documentation about how to use the write ahead log?
Thanks,
Jon Parise
