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From Josh Elser <josh.el...@gmail.com>
Subject Re: HBase and Accumulo
Date Wed, 19 Aug 2015 17:53:19 GMT
IMO, they are very similar. Lots of smart people on both sides making 
really good changes.

I think HBase has a lot more instrumentation and understanding on the 
resources a cluster will use. For example, I think it's much clearer the 
resources and threads that the RPC server will use. This is much more 
obtuse (and grows/shrinks on its own in Accumulo). I think this also 
drifts into the HBase API usage too -- I have a much better 
understanding of what needs to be managed with HBase. This is a little 
more obtuse in Accumulo for new users.

I also think HBase has a much better understanding and tuning of the 
read path. I would trust consistently performing (SLA bound) workloads 
on HBase much more than Accumulo just because there hasn't been (public) 
work that is or has happened in Accumulo.

On the other side, it's been years since I've seen data loss or 
assignment bugs in Accumulo. Around 1.1.0, the bugs that Enis and Stack 
fixed shocked me. I was rather surprised to see these kinds of bugs crop 
up, and really worried me when I spent quite a lot of time trying to 
understand the bugs. Personally, I would trust Accumulo to be thrown off 
a cliff and still keep chugging (again, because I've done this myself). 
I don't have this confidence with HBase (yet).

Specifically WRT security since you brought it up. Last I tried to play 
with the cell-level security APIs in HBase, it seemed very obtuse to me. 
Perhaps I was just dense and didn't find the right sort of instructions. 
I think where security is critical, I would trust Accumulo more because 
it's been very fleshed out over many years and been a part of the core 
model since the start. I felt that HBase is still in a shake-down phase. 
(again, I don't want to be argumentative -- it's just my personal 
experience to date using the code and watching JIRA issues)

The HBase coprocessors and Accumulo iterators difference will still 
stand (they are not equivalent features and solve different problems, 
IMO). Coprocessors enable quite a bunch of interesting things (notably, 
Phoenix). At the same time, I like the functional-conciseness in how I 
can represent some problems using Accumulo iterators.

Ultimately, consider the use cases, evaluate the solutions and make your 
decision off of empirical evidence. That's the only way to really make a 
decision :)

Jerry He wrote:
> Hi, folks
> We have people that are evaluating HBase vs Accumulo.
> Security is an important factor.
> But I think after the Cell security was added in HBase, there is no more
> real gap compared to Accumulo.
> I know we have both HBase and Accumulo experts on this list.
> Could someone shred more light?
> I am looking for real gap comparing HBase to Accumulo if there is any so
> that I can be prepared to address them. This is not limited to the security
> area.
> There are differences in some features and implementations. But they don't
> see like real 'gaps'.
> Any comments and feedbacks are welcome.
> Thanks,
> Jerry

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