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From Alexandre Jaquet <alexjaq...@gmail.com>
Subject Re: random timestamp insert
Date Tue, 16 Jun 2009 20:04:22 GMT
Hello,

I'm also evaluting hbase for some applications and found an old post about
transactions and concurrent access

http://osdir.com/ml/java.hadoop.hbase.user/2008-05/msg00169.html

Does timestamp is really better than Long versioning ?

Any workaround ?

2009/6/16 Xinan Wu <wuxinan@gmail.com>

> I am aware that inserting data into hbase with random timestamp order
> results indeterminate result.
>
> e.g. comments here
> https://issues.apache.org/jira/browse/HBASE-1249#action_12682369
>
> I've personally experienced indeterminate results before when I insert
> in random timestamp order (i.e., multiple versions with same timestamp
> in the same cell, out-of-order timestamp when getting multiple
> versions).
>
> In other words, we don't want to go back in time in inserting cells.
> Deletion is ok. But is updating pretty much the same story as
> inserting?
>
> i.e., if I make sure the timestamp does exist in the cell, and then I
> _update_ it with that timestamp (and same value length), sometimes
> hbase still just inserts a new version without touching the old one,
> and of course timestamps of this cell becomes out of order. Even if I
> delete all versions in that cell and reinsert in the time order, the
> result is still out of order. I assume if I do a major compact between
> delete all and reinsert, it would be ok, but that's not a good
> solution. Is there any good way to update a version of a cell in the
> past? or that simply won't work?
>
> Thanks,
>

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