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From Ted Yu <yuzhih...@gmail.com>
Subject Re: Column families
Date Fri, 23 Jun 2017 13:53:43 GMT
Per column family flush is in hbase 1.1 onwards

Cheers

On Fri, Jun 23, 2017 at 2:18 AM, Alexander Ilyin <alexander@weborama.com>
wrote:

> Brian, Ted, thank you for your answers.
>
> Ted, could you point out the HBase version where per column family flush
> first appeared?
>
>
> On Thu, Jun 22, 2017 at 4:06 PM, Ted Yu <yuzhihong@gmail.com> wrote:
>
> > bq. HBase doesn't do well with more than 2-3 column families
> >
> > The above is out of date - we have per column family flush which would
> > reduce the number of small hfiles.
> >
> > bq. Why can't we just create several tables instead?
> >
> > Currently hbase doesn't provide transaction across region boundary. This
> > means with more than one table, burden is on application code to
> > achieve transaction
> > where needed.
> > Since the multiple tables tend to have same row key design as you
> > mentioned, region servers carry more regions, increasing load on
> assignment
> > manager / balancer, etc.
> >
> > Cheers
> >
> > On Thu, Jun 22, 2017 at 5:44 AM, Alexander Ilyin <alexander@weborama.com
> >
> > wrote:
> >
> > > Hi,
> > >
> > > A general question regarding column families. It is said in the doc
> that
> > > HBase doesn't do well with more than 2-3 column families because
> flushing
> > > and compactions are done on a per region basis which should be
> addressed
> > in
> > > the future: http://hbase.apache.org/book.html#number.of.cfs
> > >
> > > Is it still the case in new versions of HBase or there were some
> > > improvements on this?
> > >
> > > I also don't understand why using several column families might be
> useful
> > > even if data access is column scoped. Why can't we just create several
> > > tables instead? Row key is stored with every cell anyway and it's
> > possible
> > > to filter by column when querying.
> > >
> > > In general, I don't see when it might make sense to have more than one
> > > column family in a table with current limitations.
> > >
> > > Thanks in advance.
> > >
> >
>

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