Skimmed over the doc and most-recent patch -- while this will hurt a
little bit, we're already on the hook to mitigate the hurt we're doign
with PBs->POJOs. Let's fix it all up since Appy has already gone this
far with it.
+1
On 9/21/17 3:20 PM, Stack wrote:
Folks ok w/ this proposed change for hbase2? Lots of disruption but lots of
benefit. I'm game and will help land this in next few days unless objection?
Thanks,
S
On Fri, Sep 8, 2017 at 4:29 PM, Stack <st...@duboce.net> wrote:
On Wed, Sep 6, 2017 at 5:07 PM, Apekshit Sharma <a...@cloudera.com> wrote:
Hi
Links: HBASE-17732 <https://issues.apache.org/jira/browse/HBASE-17732>,
Code
Review <https://reviews.apache.org/r/62141/>
With 2.0 beta 1 approaching, this seems to be the ripe time to make much
needed coprocessor design changes. Here's a summary of what's changing
(from jira description):
The two main changes are:
- *Adding template for coprocessor type to CoprocessorEnvironment i.e.
interface CoprocessorEnvironment<C extends Coprocessor>*
- Enables us to load only relevant coprocessors in hosts. Right now
each type of host loads all types of coprocs and it's only during
execOperation that it checks if the coproc is of correct type i.e.
XCoprocessorHost will load XObserver, YObserver, and all others,
and will
check in execOperation if coproc instanceOf XObserver and ignore
the rest.
- Allow sharing of a bunch functions/classes which are currently
duplicated in each host. For eg. CoprocessorOperations,
CoprocessorOperationWithResult, execOperations().
- *Introduce 4 coprocessor classes and use composition between these
new
classes and and old observers*
- The real gold here is, moving forward, we'll be able to break down
giant everything-in-one observers (masterobserver has 100+
functions) into
smaller, more focused observers. These smaller observer can then
have
different compat guarantees!!
There's a more detailed analysis/design doc which discusses motivation
behind the changes:
https://docs.google.com/document/d/1PBEnaqyJeiHvALFswF_yl81-
rOpQmZuixCDua-LT9X4/edit
Impact on third party:
- Although it'll break every coprocessor out there, the change to make
things work again will be very tiny. Look at the changes I had to do to
Coprocessors in our tests. It's just few simple lines.
- CoprocessorService will be backward compatible.
Status: Almost code complete. Fixing last 2-3 tests and adding a test to
ensure backward compatibility of CoprocessorService.
------------------------------------------------------------
------------------------------------
Jira: https://issues.apache.org/jira/browse/HBASE-17732
Code review: https://reviews.apache.org/r/62141/
Doc:
https://docs.google.com/document/d/1PBEnaqyJeiHvALFswF_yl81-
rOpQmZuixCDua-LT9X4/edit
------------------------------------------------------------
------------------------------------
-- Appy
Nice writeup. I make an attempt at summarizing benefit in a comment. Fix
if I have it wrong. Downside is total disruption (though argument is the
change to come up on new framework is small change) though we are having
total disruption anyways in 2.0 for Coprocessors.
This refactor does nothing for long-standing issues like HBASE-15071
or HBASE-6992 ?
Thanks Appy,
S
