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From "Buttler, David" <buttl...@llnl.gov>
Subject RE: Delete reveals older version of a column even when VERSIONS=1
Date Tue, 01 Feb 2011 00:35:02 GMT
The way I understand it is that old versions do not actually disappear until a compaction occurs.
 A compaction should occur once per day unless you have changed the major compaction settings,
or whenever a region splits.

Dave



-----Original Message-----
From: Mike Percy [mailto:mpercy@yahoo-inc.com] 
Sent: Friday, January 28, 2011 6:10 PM
To: user@hbase.apache.org
Subject: Re: Delete reveals older version of a column even when VERSIONS=1

Hmm... how does this relate to setting VERSIONS => '1'? By setting # of versions to 1 are
we getting some space benefit over say VERSIONS => '10'?

Thanks,
Mike

On Jan 28, 2011, at 5:47 PM, Ryan Rawson wrote:

> I would call it 'a surprising, perhaps unexpected consequence of our
> storage model'.
> 
> There are 2 types of deletes in hbase, you are doing type (a) "delete
> a single version", but you probably want type (b) "delete all versions
> in this column"
> 
> 
> 
> On Fri, Jan 28, 2011 at 5:43 PM, Mike Percy <mpercy@yahoo-inc.com> wrote:
>> Hi folks,
>> I am seeing some unexpected behavior with HBase 0.20.6 when deleting columns. Our
cluster has been running for some time however we recently upgraded from Hbase 0.20.3. The
family I am writing to is specified as VERSIONS => '1' when doing a describe, yet HBase
appears to be maintaining several versions of the columns.
>> 
>> Below is a shell session demonstrating the problem. Is this a configuration problem,
as-designed, or possibly a bug?
>> 
>> Thanks,
>> Mike
>> 
>> hbase(main):004:0> put 'table', 'row', 'family:qual', '1'
>> 0 row(s) in 0.0110 seconds
>> hbase(main):007:0> get 'table', 'row'
>> COLUMN                       CELL
>>  family:qual                   timestamp=1296264772717, value=1
>> 1 row(s) in 0.0080 seconds
>> hbase(main):008:0> put 'table', 'row', 'family:qual', '2'
>> 0 row(s) in 0.0020 seconds
>> hbase(main):009:0> put 'table', 'row', 'family:qual', '3'
>> 0 row(s) in 0.0020 seconds
>> hbase(main):010:0> get 'table', 'row'
>> COLUMN                       CELL
>>  family:qual                   timestamp=1296264797169, value=3
>> 1 row(s) in 0.0030 seconds
>> hbase(main):011:0> delete 'table', 'row', 'family:qual'
>> 0 row(s) in 0.0040 seconds
>> hbase(main):012:0> get 'table', 'row'
>> COLUMN                       CELL
>>  family:qual                   timestamp=1296264795365, value=2
>> 1 row(s) in 0.0630 seconds
>> hbase(main):013:0> delete 'table', 'row', 'family:qual'
>> 0 row(s) in 0.0360 seconds
>> hbase(main):014:0> get 'table', 'row'
>> COLUMN                       CELL
>>  family:qual                   timestamp=1296264772717, value=1
>> 1 row(s) in 0.0030 seconds
>> hbase(main):013:0> delete 'table', 'row', 'family:qual'
>> 0 row(s) in 0.0360 seconds
>> hbase(main):016:0> get 'table', 'row'
>> COLUMN                       CELL
>> 0 row(s) in 0.0030 seconds
>> 
>> 


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