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From "Sharma, Avani" <agsha...@ebay.com>
Subject RE: speed up reads in hBase
Date Tue, 29 Jun 2010 23:05:01 GMT
Max 6 versions. The rows are very small. I am currently running a prototype to see if HBase
will work for our application in a real-time environment.
The initial result shows slower than what-we-need performance.

I am not querying older versions. I am querying the latest in the experiment results I sent
across.
I ran experiments, and the timing doesn't change for querying 6 versions old data or by not
using versioning (instead create key_timestamp as the row key).


I was hoping there would be ways to optimize the querying of latest version (forget about
older versions ).

-Avani

-----Original Message-----
From: Todd Lipcon [mailto:todd@cloudera.com] 
Sent: Tuesday, June 29, 2010 3:21 PM
To: user@hbase.apache.org
Subject: Re: speed up reads in hBase

Hi Avani,

There are currently some optimizations that Jonathan Gray is working on to
make selection of specific time ranges more efficient.

How many versions are retained for the rows in this column family?

-Todd

On Tue, Jun 29, 2010 at 1:08 PM, Sharma, Avani <agsharma@ebay.com> wrote:

> Rows are very small (like 50 bytes max). I am accessing the latest version
> after setting  timerange.
>
>        HTable table = new HTable(new HBaseConfiguration(), table_name);
>
>        Get getRes = new Get(Bytes.toBytes(lkp_key));
>
>        long maxStamp  = new SimpleDateFormat("yyyyMMdd").parse(date_for_ts,
> new ParsePosition(0)).getTime();
>        getRes.setTimeRange(0, maxStamp);
>
>        Result r   = table.get(getRes);
>        NavigableMap<byte[], byte[]> kvMap   =
> r.getFamilyMap((Bytes.toBytes("data")));
>
> -----Original Message-----
> From: Michael Segel [mailto:michael_segel@hotmail.com]
> Sent: Tuesday, June 29, 2010 12:46 PM
> To: user@hbase.apache.org
> Subject: RE: speed up reads in hBase
>
>
>
> How wide are your rows?
> Are you accessing the last version or pulling back all of the versions per
> row?
> > From: agsharma@ebay.com
> > To: user@hbase.apache.org
> > Date: Tue, 29 Jun 2010 12:11:46 -0700
> > Subject: speed up reads in hBase
> >
> >
> > I have about 2.8M rows in my HBase table with multiple versions ( max 6)
> .
> >
> > When I try to lookup 1000 records, it takes a total time of 20 minutes !
> Per read takes about a second or more.
> > Will appreciate any pointers on speeding these ?
> >
> > Thanks,
> > -Avani
>
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-- 
Todd Lipcon
Software Engineer, Cloudera

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