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From Anoop John <anoop.hb...@gmail.com>
Subject Re: writing and reading from a region at once
Date Fri, 26 Apr 2013 04:08:00 GMT
>But it seems that I'm losing writes somewhere, is it possible the writes
could fail silently

Which version you are using?  How you say writes missed silently?  The
current read, which was going on, has not returned the row that you just
wrote?  Or you have created a new scan after wards and in that also the
written data is missing?

-Anoop-

On Fri, Apr 26, 2013 at 3:04 AM, Jean-Daniel Cryans <jdcryans@apache.org>wrote:

> Inline.
>
> J-D
>
>
> On Thu, Apr 25, 2013 at 1:09 PM, Aaron Zimmerman <
> azimmerman@sproutsocial.com> wrote:
>
> > Hi,
> >
> >   If a region is being written to, and a scanner takes a lease out on the
> > region, what will happen to the writes?  Is there a concept of
> "Transaction
> > Isolation Levels"?
> >
>
> There's MVCC, so reads can happen while someone else is writing. What you
> should expect from HBase is "read committed".
>
>
> >
> >   I don't see errors in Puts while the tables are being scanned?  But it
> > seems that I'm losing writes somewhere, is it possible the writes could
> > fail silently?
> >
>
>  Is it temporary while you're scanning or there's really data missing at
> the end of the day? The former might happen on some older HBase versions
> while the latter should never happen unless you lower the durability level
> yourself and have machine failures.
>
> J-D
>

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