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Posted to user@hbase.apache.org by Michael Dagaev <mi...@gmail.com> on 2008/12/17 16:59:01 UTC
Row with many-many columns
Hi, all
Let there is a row with A, B, and C column families. Let C column
family many-many columns (qualifiers). As I understand, retrieve of
such a row is slow. What if I retrieve only A and B columns but not C
? I guess it will be much faster. Is it correct?
Thank you for your cooperation,
M.
Re: Row with many-many columns
Posted by Slava Gorelik <sl...@gmail.com>.
Correct, my mistake:"...Each column family in a region is managed by an *
HStore*. Each HStore may have one or more *MapFiles* (a Hadoop HDFS file
type) that is very similar to a Google *SSTable*. Like SSTables, MapFiles
are immutable once closed. MapFiles are stored in the Hadoop HDFS..."
On Thu, Dec 18, 2008 at 6:59 PM, Erik Holstad <er...@gmail.com> wrote:
> Hi!
> I'm not totally sure about this, but I think that 1 family is stored in 1
> HStore which
> consists of multiple HStoreFiles which in their turn consists of mapfiles
> and an index file.
>
> Regards Erik
>
> On Wed, Dec 17, 2008 at 8:52 AM, Slava Gorelik <slava.gorelik@gmail.com
> >wrote:
>
> > Hi.
> >
> > I think it should be faster, even for the reason that each column family
> is
> > separate map file (correct me if i wrong).It means when you will ask for
> > specific column family, HBase will not open other map files.
> > Btw, the functionality to get particular column family will be released
> in
> > 0.19 : https://issues.apache.org/jira/browse/HBASE-857
> >
> >
> > Best Regards.
> >
> >
> > On Wed, Dec 17, 2008 at 5:59 PM, Michael Dagaev <
> michael.dagaev@gmail.com
> > >wrote:
> >
> > > Hi, all
> > >
> > > Let there is a row with A, B, and C column families. Let C column
> > > family many-many columns (qualifiers). As I understand, retrieve of
> > > such a row is slow. What if I retrieve only A and B columns but not C
> > > ? I guess it will be much faster. Is it correct?
> > >
> > > Thank you for your cooperation,
> > > M.
> > >
> >
>
Re: Row with many-many columns
Posted by Erik Holstad <er...@gmail.com>.
Hi!
I'm not totally sure about this, but I think that 1 family is stored in 1
HStore which
consists of multiple HStoreFiles which in their turn consists of mapfiles
and an index file.
Regards Erik
On Wed, Dec 17, 2008 at 8:52 AM, Slava Gorelik <sl...@gmail.com>wrote:
> Hi.
>
> I think it should be faster, even for the reason that each column family is
> separate map file (correct me if i wrong).It means when you will ask for
> specific column family, HBase will not open other map files.
> Btw, the functionality to get particular column family will be released in
> 0.19 : https://issues.apache.org/jira/browse/HBASE-857
>
>
> Best Regards.
>
>
> On Wed, Dec 17, 2008 at 5:59 PM, Michael Dagaev <michael.dagaev@gmail.com
> >wrote:
>
> > Hi, all
> >
> > Let there is a row with A, B, and C column families. Let C column
> > family many-many columns (qualifiers). As I understand, retrieve of
> > such a row is slow. What if I retrieve only A and B columns but not C
> > ? I guess it will be much faster. Is it correct?
> >
> > Thank you for your cooperation,
> > M.
> >
>
Re: Row with many-many columns
Posted by Slava Gorelik <sl...@gmail.com>.
Hi.
I think it should be faster, even for the reason that each column family is
separate map file (correct me if i wrong).It means when you will ask for
specific column family, HBase will not open other map files.
Btw, the functionality to get particular column family will be released in
0.19 : https://issues.apache.org/jira/browse/HBASE-857
Best Regards.
On Wed, Dec 17, 2008 at 5:59 PM, Michael Dagaev <mi...@gmail.com>wrote:
> Hi, all
>
> Let there is a row with A, B, and C column families. Let C column
> family many-many columns (qualifiers). As I understand, retrieve of
> such a row is slow. What if I retrieve only A and B columns but not C
> ? I guess it will be much faster. Is it correct?
>
> Thank you for your cooperation,
> M.
>