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From Lin Ma <lin...@gmail.com>
Subject Re: batch update question
Date Wed, 05 Sep 2012 16:04:45 GMT
Thank you Stack for the details directions!

1. You are right, I have not met with any real row contention issues. My
purpose is understanding the issue in advance, and also from this issue to
understand HBase generals better;
2. For the comments from API Url page you referred -- "If
false, the update is buffered until the internal buffer is full.", I
confused what is the buffer? Buffer at client side or buffer in region
server? Is there a way to configure its size to hold until flushing?
3. Why batch could resolve contention on the same raw issue in theory,
compared to non-batch operation? Besides preparation the solution in my
mind in advance, I want to learn a bit about why. :-)


On Wed, Sep 5, 2012 at 4:00 AM, Stack <stack@duboce.net> wrote:

> On Sun, Sep 2, 2012 at 2:13 AM, Lin Ma <linlma@gmail.com> wrote:
> > Hello guys,
> >
> > I am reading the book "HBase, the definitive guide", at the beginning of
> > chapter 3, it is mentioned in order to reduce performance impact for
> > clients to update the same row (lock contention issues for automatic
> > write), batch update is preferred. My questions is, for MR job, what are
> > the batch update methods we could leverage to resolve the issue? And for
> > API client, what are the batch update methods we could leverage to
> resolve
> > the issue?
> >
> Do you actually have a problem where there is contention on a single row?
> Use methods like
> http://hbase.apache.org/apidocs/org/apache/hadoop/hbase/client/HTable.html#put(java.util.List)
> or the batch methods listed earlier in the API.  You should set
> autoflush to false too:
> http://hbase.apache.org/apidocs/org/apache/hadoop/hbase/client/HTableInterface.html#isAutoFlush()
> Even batching, a highly contended row might hold up inserts... but for
> sure you actually have this problem in the first place?
> St.Ack

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