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Posted to user@hbase.apache.org by JinChao Wen <we...@gmail.com> on 2011/01/26 08:14:13 UTC
question about long column family name and column name
Hi all,
If there are lots of very long column family name and column name in my
table, is there any performance impact on query?
thx.
JinChao
Re: question about long column family name and column name
Posted by JinChao Wen <we...@gmail.com>.
Thank you all.
2011/1/27 Matt Corgan <mc...@hotpads.com>
> The full row name, column family name, and column qualifier are stored with
> every cell (called a KeyValue). Using gzip or lzo compression can greatly
> reduce the size of the data stored on disk, and prefix compression could
> eventually reduce the size of the data stored in memory.
>
> But, to your question about performance, most get/scan operations require
> iterating through and comparing the byte arrays that back the KeyValues, so
> the more bytes it has to iterate over, the slower it will be. However,
> we're talking about sequential memory access which computers are very good
> at, so what *overall *performance increase you can expect from shortening
> the values is hard to say.
>
>
> On Wed, Jan 26, 2011 at 12:54 PM, Bill Graham <bi...@gmail.com>
> wrote:
>
> > I can't say from experience, but here's a thread that implies that
> > shorter column names are better.
> >
> > http://search-hadoop.com/m/oWZQd161GI22
> >
> > On Tue, Jan 25, 2011 at 11:14 PM, JinChao Wen <we...@gmail.com>
> > wrote:
> > > Hi all,
> > >
> > > If there are lots of very long column family name and column name in
> my
> > > table, is there any performance impact on query?
> > >
> > > thx.
> > >
> > >
> > > JinChao
> > >
> >
>
Re: question about long column family name and column name
Posted by Matt Corgan <mc...@hotpads.com>.
The full row name, column family name, and column qualifier are stored with
every cell (called a KeyValue). Using gzip or lzo compression can greatly
reduce the size of the data stored on disk, and prefix compression could
eventually reduce the size of the data stored in memory.
But, to your question about performance, most get/scan operations require
iterating through and comparing the byte arrays that back the KeyValues, so
the more bytes it has to iterate over, the slower it will be. However,
we're talking about sequential memory access which computers are very good
at, so what *overall *performance increase you can expect from shortening
the values is hard to say.
On Wed, Jan 26, 2011 at 12:54 PM, Bill Graham <bi...@gmail.com> wrote:
> I can't say from experience, but here's a thread that implies that
> shorter column names are better.
>
> http://search-hadoop.com/m/oWZQd161GI22
>
> On Tue, Jan 25, 2011 at 11:14 PM, JinChao Wen <we...@gmail.com>
> wrote:
> > Hi all,
> >
> > If there are lots of very long column family name and column name in my
> > table, is there any performance impact on query?
> >
> > thx.
> >
> >
> > JinChao
> >
>
Re: question about long column family name and column name
Posted by Bill Graham <bi...@gmail.com>.
I can't say from experience, but here's a thread that implies that
shorter column names are better.
http://search-hadoop.com/m/oWZQd161GI22
On Tue, Jan 25, 2011 at 11:14 PM, JinChao Wen <we...@gmail.com> wrote:
> Hi all,
>
> If there are lots of very long column family name and column name in my
> table, is there any performance impact on query?
>
> thx.
>
>
> JinChao
>