hbase-dev mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From 杨苏立 Yang Su Li <yangs...@gmail.com>
Subject Re: Is HBase RPC-Handling idempotent for reads?
Date Sun, 09 Apr 2017 22:47:50 GMT
We are trying to implement speculative rpc handling for our workloads. So
we want allow RPC Handler to stop executing an RPC call, put it back to the
queue, and later re-execute it.

If at time t1, we execute and RPC call half way, aborts, and put the call
back to the queue.
Then at time t2 another RPC handler picks the call and re-execute it.
I understand that we might get a different mvcc number and different
results at t2 compared to we execute it at t1.
My question is that: would this situation any different compared to the
situation where the call was never executed at t1, and is executed at t2
for the first time.


My guess is that since at t1 we may already gotten an mvcc number, so it
might potentially cause some write conflicts and certain write operations
to retry. But correctness wise, is there any difference?

Thanks a lot!

Suli


On Sun, Apr 9, 2017 at 5:14 PM, Jerry He <jerryjch@gmail.com> wrote:

> I don't know what your intention and your context are.
>
> You may get a different mvcc number and get different results next time
> around if there are concurrent writes.
>
> Thanks,
>
> Jerry
>
> On Sun, Apr 9, 2017 at 12:48 PM 杨苏立 Yang Su Li <yangsuli@gmail.com> wrote:
>
> > Hi,
> >
> > I am wondering, for read requests like Get/MultiGet/Scan, is the RPC
> > handling idempotent in HBase?
> >
> > More specifically, if in the middle of RPC handling we stop the handling
> > threads, puts the RPC call back to the queue, and later another RPC
> Handler
> > picks up this call and starts all over again, will the result be the same
> > as if this call is being handled for the first time now? Or are their any
> > unexpected side effects?
> >
> > Thanks!
> >
> > Suli
> >
> > --
> > Suli Yang
> >
> > Department of Physics
> > University of Wisconsin Madison
> >
> > 4257 Chamberlin Hall
> > Madison WI 53703
> >
>



-- 
Suli Yang

Department of Physics
University of Wisconsin Madison

4257 Chamberlin Hall
Madison WI 53703

Mime
  • Unnamed multipart/alternative (inline, None, 0 bytes)
View raw message