Home | About | Sematext search-lucene.com search-hadoop.com
 Search Hadoop and all its subprojects:

Switch to Threaded View
HBase, mail # dev - [Shadow Regions / Read Replicas ]


Copy link to this message
-
Re: [Shadow Regions / Read Replicas ]
Devaraj Das 2013-12-03, 19:26
On Tue, Dec 3, 2013 at 11:07 AM, Enis Söztutar <[EMAIL PROTECTED]> wrote:

> Thanks Jon for bringing this to dev@.
>
>
> On Mon, Dec 2, 2013 at 10:01 PM, Jonathan Hsieh <[EMAIL PROTECTED]> wrote:
>
> > Fundamentally, I'd prefer focusing on making HBase "HBasier" instead of
> > tackling a feature that other systems architecturally can do better
> > (inconsistent reads).   I consider consistent reads/writes being one of
> > HBase's defining features. That said, I think read replicas makes sense
> and
> > is a nice feature to have.
> >
>
> Our design proposal has a specific use case goal, and hopefully we can
> demonstrate the
> benefits of having this in HBase so that even more pieces can be built on
> top of this. Plus I imagine this will
> be a widely used feature for read-only tables or bulk loaded tables. We are
> not
> proposing of reworking strong consistency semantics or major architectural
> changes. I think by
> having the tables to be defined with replication count, and the proposed
> client API changes (Consistency definition)
> plugs well into the HBase model rather well.
>
>
>
The good part is that the proposed architecture and the underlying
implementation can be extended to provide strong consistency semantics in
the presence of shadows. I guess much of the work that is being proposed
here would be needed even there.
> >
> > A few thoughts:
> > - Both approaches need to have more failure handling cases thought out.
> >
>
> Agreed. We cover most of the assignment / master side of things in the doc
> though.
>
>
> > - I think the two goals are both worthy on their own each with their own
> > optimal points.  We should in the design makes sure that we can support
> > both goals.
> >
>
> I think our proposal is consistent with your doc, and we have considered
> secondary region promotion
> in the future section. It would be good if you can review and comment on
> whether you see any points
> missing.
>
>
> > - I want to making sure the proposed design have a path for optimal
> > fast-consistent read-recovery.
> >
>
> We think that it is, but it is a secondary goal for the initial work. I
> don't see any reason why secondary
> promotion cannot be build on top of this, once the branch is in a better
> state.
>
>
> >
> > Jon.
> >
> >
> > On Mon, Dec 2, 2013 at 9:54 PM, Jonathan Hsieh <[EMAIL PROTECTED]> wrote:
> >
> > > HBASE-10070 [1]  looks to be heading into a discussion more apt for the
> > > mailing list than in the jira. Moving this to the dev list for threaded
> > > discussion.  I'll start a few threads by replying to this thread with
> > > edited titles
> > >
> > > [1] https://issues.apache.org/jira/browse/HBASE-10070
> > >
> > > --
> > > // Jonathan Hsieh (shay)
> > > // Software Engineer, Cloudera
> > > // [EMAIL PROTECTED]
> > >
> > >
> >
> >
> >
> > --
> > // Jonathan Hsieh (shay)
> > // Software Engineer, Cloudera
> > // [EMAIL PROTECTED]
> >
>

--
CONFIDENTIALITY NOTICE
NOTICE: This message is intended for the use of the individual or entity to
which it is addressed and may contain information that is confidential,
privileged and exempt from disclosure under applicable law. If the reader
of this message is not the intended recipient, you are hereby notified that
any printing, copying, dissemination, distribution, disclosure or
forwarding of this communication is strictly prohibited. If you have
received this communication in error, please contact the sender immediately
and delete it from your system. Thank You.