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HBase >> mail # dev >> [UPDATE] Finishing up 0.96 --> WAS Re: 0.95 and 0.96 remaining issues


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Re: [UPDATE] Finishing up 0.96 --> WAS Re: 0.95 and 0.96 remaining issues
On Sun, Jul 28, 2013 at 4:01 PM, Stack <[EMAIL PROTECTED]> wrote:

> I just did a review of tags.  They look like they need a good bit of
> work yet.
>

Yes that patch I put up on RB is the one that was cluster tested and
profiled. Let me work with Ram about getting the latest up there. We also
needed to get a sense of what can work. For that, please correct me if I am
mistaken about any of the following:

   - An HFileV3 is fine in concept.

   - We subclass KeyValue (as TaggedKeyValue) to avoid changing KeyValue's
   serialization code and to avoid heap size inflation for the no tags case.
   This is fine modulo issues with encapsulation.

   - Not plumbing tags all the way through to the client as to minimize
   risk in 0.96 is ok. (And this benefits security as a bonus and is also fine
   for strictly server-side tag use cases.) This ties in to the above as to
   why a subclass is needed to carry around tags as in memory state, like
   memstoreTS.

   - Changing the encoders is fine, since they are shared by all HFile
   implementations. Of course as few changes as possible. Tag specific changes
   there - method signature changes mostly - are currently workable but ugly,
   but we can handle that in another pass by subclassing more HFile classes to
   carry V3 specific state.
--
Best regards,

   - Andy

Problems worthy of attack prove their worth by hitting back. - Piet Hein
(via Tom White)