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From Vladimir Rodionov <vrodio...@carrieriq.com>
Subject RE: Performance between HBaseClient scan and HFileReaderV2
Date Thu, 02 Jan 2014 18:30:51 GMT
HBase scanner MUST guarantee correct order of KeyValues (coming from different HFile's),
filter condition+ filter condition on included column families and qualifiers, time range,
max versions and correctly process deleted cells.
Direct HFileReader does nothing from the above list.

Best regards,
Vladimir Rodionov
Principal Platform Engineer
Carrier IQ, www.carrieriq.com
e-mail: vrodionov@carrieriq.com

________________________________________
From: Jerry Lam [chilinglam@gmail.com]
Sent: Thursday, January 02, 2014 7:56 AM
To: user
Subject: Re: Performance between HBaseClient scan and HFileReaderV2

Hi Tom,

Good point. Note that I also ran the HBaseClient performance test several
times (as you can see from the chart). The caching should also benefit the
second time I ran the HBaseClient performance test not just benefitting the
HFileReaderV2 test.

I still don't understand what makes the HBaseClient performs so poorly in
comparison to access directly HDFS. I can understand maybe a factor of 2
(even that it is too much) but a factor of 8 is quite unreasonable.

Any hint?

Jerry



On Sun, Dec 29, 2013 at 9:09 PM, Tom Hood <tom.w.hood@gmail.com> wrote:

> I'm also new to HBase and am not familiar with HFileReaderV2.  However, in
> your description, you didn't mention anything about clearing the linux OS
> cache between tests.  That might be why you're seeing the big difference if
> you ran the HBaseClient test first, it may have warmed the OS cache and
> then HFileReaderV2 benefited from it.  Just a guess...
>
> -- Tom
>
>
>
> On Mon, Dec 23, 2013 at 12:18 PM, Jerry Lam <chilinglam@gmail.com> wrote:
>
> > Hello HBase users,
> >
> > I just ran a very simple performance test and would like to see if what I
> > experienced make sense.
> >
> > The experiment is as follows:
> > - I filled a hbase region with 700MB data (each row has roughly 45
> columns
> > and the size is 20KB for the entire row)
> > - I configured the region to hold 4GB (therefore no split occurs)
> > - I ran compactions after the data is loaded and make sure that there is
> > only 1 region in the table under test.
> > - No other table exists in the hbase cluster because this is a DEV
> > environment
> > - I'm using HBase 0.92.1
> >
> > The test is very basic. I use HBaseClient to scan the entire region to
> > retrieve all rows and all columns in the table, just iterating all
> KeyValue
> > pairs until it is done. It took about 1 minute 22 sec to complete. (Note
> > that I disable block cache and uses caching size about 10000).
> >
> > I ran another test using HFileReaderV2 and scan the entire region to
> > retrieve all rows and all columns, just iterating all keyValue pairs
> until
> > it is done. It took 11 sec.
> >
> > The performance difference is dramatic (almost 8 times faster using
> > HFileReaderV2).
> >
> > I want to know why the difference is so big or I didn't configure HBase
> > properly. From this experiment, HDFS can deliver the data efficiently so
> it
> > is not the bottleneck.
> >
> > Any help is appreciated!
> >
> > Jerry
> >
> >
>

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