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From Ryan Rawson <ryano...@gmail.com>
Subject Re: About the table on time dimension.
Date Fri, 22 May 2009 07:33:11 GMT
Hey,

those 2 entries have different rows ids, with different timestamps (same
column, same value).

btw, setting timestamps in a non-monotonically increasing order may cause
performance and certain correctness issues on 0.20.  Best to avoid it for
production code if you can.

On Fri, May 22, 2009 at 12:27 AM, Edward J. Yoon <edwardyoon@apache.org>wrote:

> OK, It's my typos, not my point. Result is same even if 'versions' is
> 1. Anyway, Do you think 'version mixed' table should be appeared?
>
> hbase(main):025:0> describe 't1'
> {NAME => 't1', IS_ROOT => 'false', IS_META => 'false', FAMILIES =>
> [{NAME => 'f1', BLOOMFILTER => 'false', COM
> PRESSION => 'NONE', VERSIONS => '1', LENGTH => '2147483647', TTL =>
> '-1', IN_MEMORY => 'false', BLOCKCACHE =>
> 'false'}], INDEXES => []}
> 1 row(s) in 0.0230 seconds
> hbase(main):028:0> scan 't1'
> ROW                          COLUMN+CELL
>  r1                          column=f1:, timestamp=1, value=value
>  r2                          column=f1:, timestamp=3, value=value
> 2 row(s) in 0.0240 seconds
>
> On Fri, May 22, 2009 at 3:41 PM, Ryan Rawson <ryanobjc@gmail.com> wrote:
> > Hey,
> >
> > I generally don't think of hbase entries like spreadsheets with 'nulls'
> in
> > the empty locations.  Its really more like an adjacency list, where the
> data
> > is only there when it's there.
> >
> > But I was referring to your create, the key is 'VERSIONS' not 'VERSION'.
> > create 'table', {NAME=>'family', VERSIONS=>1}
> >
> >
> >
> > On Thu, May 21, 2009 at 11:35 PM, Edward J. Yoon <edwardyoon@apache.org
> >wrote:
> >
> >> Let's assume, there are two 2 * 2 sparse tables as below.
> >>
> >> t1
> >> ----
> >> null 2
> >> -1 null
> >>
> >> t2
> >> ----
> >> -3 null
> >> null null
> >>
> >> I'll put these tables to table 'x'. And, The table 'x' will handle
> >> only one version. Then, 't2' should be appeared, not 't1' + 't2'
> >> table.
> >>
> >> Currently, Hbase shows the 't1' + 't2' table as below.
> >> ----
> >> -3(t2) 2(t1)
> >> -1(t1) null (what is this?)
> >>
> >> Should I update the all 't1' entries?
> >>
> >> On Fri, May 22, 2009 at 3:11 PM, Ryan Rawson <ryanobjc@gmail.com>
> wrote:
> >> > The key is 'VERSIONS'.  Give it another shot.
> >> >
> >> > -ryan
> >> >
> >> > On Thu, May 21, 2009 at 11:07 PM, Edward J. Yoon <
> edwardyoon@apache.org
> >> >wrote:
> >> >
> >> >> hbase(main):001:0> create 't1', {NAME=> 'f1', VERSION => 1}
> >> >> hbase(main):002:0> put 't1', 'r1', 'f1' ,'value', 1
> >> >> hbase(main):007:0> put 't1', 'r2', 'f1:' ,'value', 2
> >> >>
> >> >> I made a table 't1' as above. And, When scan this,
> >> >>
> >> >> hbase(main):008:0> scan 't1'
> >> >> ROW                          COLUMN+CELL
> >> >>  r1                          column=f1:, timestamp=1, value=value
> >> >>  r2                          column=f1:, timestamp=2, value=value
> >> >> 2 row(s) in 0.0330 seconds
> >> >>
> >> >> I expected only one row 'r2' (sparse table for time t2) but there are
> >> >> two tables on time dimension. I think it's a logical bug. The 't1'
> >> >> should maintain only one version of time dimension table.
> >> >>
> >> >> What do you think?
> >> >> --
> >> >> Best Regards, Edward J. Yoon @ NHN, corp.
> >> >> edwardyoon@apache.org
> >> >> http://blog.udanax.org
> >> >>
> >> >
> >>
> >>
> >>
> >> --
> >> Best Regards, Edward J. Yoon @ NHN, corp.
> >> edwardyoon@apache.org
> >> http://blog.udanax.org
> >>
> >
>
>
>
> --
> Best Regards, Edward J. Yoon @ NHN, corp.
> edwardyoon@apache.org
> http://blog.udanax.org
>

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