Heads up on Coprocessor changes coming down the pipe (hbase-2.0.0)

[Stack <st...@duboce.net>]

Hey Phenoecioans:

I'd like to give you all a heads-up on pending changes to the Coprocessor
API and to petition your input on the coming hbase-2.0.0.

HBase internally has moved to use relocated versions of popular libraries
including protobufs. So, protobuf CP parameters changed. Interjection
points also move when you have the Master run split/merges rather than the
RegionServer as is the case in hbase-2.0.0. Other changes include our
passing Interfaces rather than Implementations so we can internally make
progress w/o disturbing Coprocessors going forward.

The list of changes is a little long, I have a running list, and we are not
done yet; e.g. a DISCUSSION thread that went up this afternoon on the dev
list is about a refactoring of CPs that would simplify the API (w/o loss of
hook points). hbase-2.0.0 is still in the alpha stage so your input now
will help us shape the final form of CP APIs (checkout the
hbase-2.0.0-alpha2 release for current state of the APIs; the list of
incompatibilies so far can be found here [1]).

The immediate issue we need input on is HBASE-18446. A few of you have
helped out already but would be sweet if we got sign off that Phoenix no
longer needs to create its own StoreFile implementation (and that a
StoreFileReader is all you need).

I know you are all busy but input would be much appreciated. The DISCUSSION
thread on the hbase dev list on COMPATIBILITY EXPECTATIONS might be a place
to start.

Thanks all,
St.Ack

1.
https://docs.google.com/document/d/1WCsVlnHjJeKUcl7wHwqb4z9iEu_ktczrlKHK8N4SZzs/edit#heading=h.723jjn18p2jr