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From Michael Seibold <seib...@in.tum.de>
Subject Re: Many columns in 0.19
Date Mon, 09 Mar 2009 10:05:34 GMT
Hi,

so how many column families per table and how many columns(=labels) per
column family are feasible in HBase 0.19.0?

column families per table: ?
columns per column family: ?

I want to use:
--------------------
column families per table: 10
columns (=labels) per column family: 100 - 150

Will I hit HDFS performance issues with that?

Kind regards,
Michael


El lun, 09-03-2009 a las 01:50 -0800, Ryan Rawson escribió:
> Don't forget, each column family is another file on disk, and file open.
> Every column family is stored in it's own mapfile, and that increases the
> load on HDFS.
> 
> This particular restriction won't ever really go away (unless we introduce
> locality groups, even then, each locality group = N families = 1 file), but
> in 0.20 it should be more feasable to have thousands of columns per family,
> or more.
> 
> -ryan
> 
> On Mon, Mar 9, 2009 at 1:47 AM, Michael Dagaev <michael.dagaev@gmail.com>wrote:
> 
> > Thank you, Ryan
> >
> > On Mon, Mar 9, 2009 at 10:28 AM, Ryan Rawson <ryanobjc@gmail.com> wrote:
> > > Sadly this is still a limit.
> > >
> > > 0.20 should make things much better.
> > >
> > > -ryan
> > >
> > > On Mon, Mar 9, 2009 at 12:23 AM, Michael Dagaev <
> > michael.dagaev@gmail.com>wrote:
> > >
> > >> Hi , all
> > >>
> > >>    I remember it was not recommended to add many columns (column
> > >> qualifiers) in Hbase 0.18
> > >> Does Hbase 0.19.0 still have this limitation?
> > >>
> > >> Thank you for your cooperation,
> > >> M.
> > >>
> > >
> >


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