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Subject: Re: How to config hbase0.94.2 to retain deleted data
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Date: Tue, 23 Oct 2012 18:01:59 -0400
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The comment clear things up. Configuration through Java code is also working=
 too. Thanks.
Yun

On Oct 22, 2012, at 12:34 AM, lars hofhansl <lhofhansl@yahoo.com> wrote:

> There currently is not. You have setup your column families to support thi=
s (Note that you only need to do that once per column family!).
> This was done for flexibility, because in many cases only some of the tabl=
es need to retain deleted cells.
>=20
> These blog posts might be helpful:
> http://hadoop-hbase.blogspot.com/2011/12/deletion-in-hbase.html
> http://hadoop-hbase.blogspot.com/2011/12/hbase-data-rentention-options.htm=
l
>=20
> -- Lars
>=20
>=20
>=20
>=20
> ----- Original Message -----
> From: yun peng <pengyunmomo@gmail.com>
> To: user@hbase.apache.org
> Cc:=20
> Sent: Sunday, October 21, 2012 5:20 PM
> Subject: Re: How to config hbase0.94.2 to retain deleted data
>=20
> Hi, Lars, that is great point. It works if I update the
> tabledescriptor with the table disabled. It looks online updating
> table descriptor generally not working...
>=20
> Besides, in addition to the java API, is there any xml knob (in
> hbase0942) that can config keepdeletedcells?
>=20
> Thanks a lot.
> Yun
>=20
> On Sun, Oct 21, 2012 at 7:04 PM, lars hofhansl <lhofhansl@yahoo.com> wrote=
:
>> Not sure that you can change the Table or Column Descriptors this way thr=
ough a coprocessor.
>> Did you try to create (or alter) the table such that keepDeleteCells is t=
rue:
>>=20
>> hbase(main):026:0> create 'usertable', {NAME=3D>'cf', KEEP_DELETED_CELLS=3D=
>true}
>> 0 row(s) in 1.1660 seconds
>>=20
>> hbase(main):027:0> put 'usertable', "key1", 'cf:c1', "v1", 99
>> 0 row(s) in 0.0320 seconds
>>=20
>> hbase(main):028:0> delete 'usertable', "key1", 'cf:c1', 100
>> 0 row(s) in 0.0050 seconds
>>=20
>> hbase(main):029:0> get 'usertable', 'key1', {COLUMN =3D> 'cf:c1', TIMESTA=
MP=3D> 99, VERSIONS =3D> 4}
>> COLUMN                CELL
>>   cf:c1                timestamp=3D99, value=3Dv1
>> 1 row(s) in 0.0150 seconds
>>=20
>> Let me know how this works for you (generally). This is a new feature I a=
dded to 0.94 to support true time-range queries.
>>=20
>> -- Lars
>>=20
>>=20
>> ----- Original Message -----
>> From: yun peng <pengyunmomo@gmail.com>
>> To: user@hbase.apache.org
>> Cc:
>> Sent: Sunday, October 21, 2012 1:53 PM
>> Subject: How to config hbase0.94.2 to retain deleted data
>>=20
>> Hi, All,
>> I want to retain all deleted key-value pairs in hbase. I have tried to
>> config HColumnDescript as follow to make it return deleted.
>>=20
>>    public void postOpen(ObserverContext<RegionCoprocessorEnvironment> e) {=

>>      HTableDescriptor htd =3D e.getEnvironment().getRegion().getTableDesc=
();
>>      HColumnDescriptor hcd =3D htd.getFamily(Bytes.toBytes("cf"));
>>      hcd.setKeepDeletedCells(true);
>>      hcd.setBlockCacheEnabled(false);
>>    }
>>=20
>> However, it does not work for me, as when I issued a delete and then quer=
y
>> by an older timestamp, the old data does not show up.
>>=20
>> hbase(main):119:0> put 'usertable', "key1", 'cf:c1', "v1", 99
>> hbase(main):120:0> put 'usertable', "key1", 'cf:c1', "v2", 101
>> hbase(main):121:0> delete 'usertable', "key1", 'cf:c1', 100
>> hbase(main):122:0> get 'usertable', 'key1', {COLUMN =3D> 'cf:c1', TIMESTA=
MP
>> =3D> 99, VERSIONS =3D> 4}
>> COLUMN                CELL
>>=20
>> 0 row(s) in 0.0040 seconds
>>=20
>> hbase(main):123:0> get 'usertable', 'key1', {COLUMN =3D> 'cf:c1', TIMESTA=
MP
>> =3D> 100, VERSIONS =3D> 4}
>> COLUMN                CELL
>>=20
>> 0 row(s) in 0.0050 seconds
>>=20
>> hbase(main):124:0> get 'usertable', 'key1', {COLUMN =3D> 'cf:c1', TIMESTA=
MP
>> =3D> 101, VERSIONS =3D> 4}
>> COLUMN                CELL
>>=20
>> cf:c1                timestamp=3D101, value=3Dv2
>>=20
>> 1 row(s) in 0.0050 seconds
>>=20
>> Note this is a new feature in 0.94.2
>> (HBASE-4536<https://issues.apache.org/jira/browse/HBASE-4536>),
>> I did not find too many sample code online, so... any one here has
>> experience in using HBASE-4536. How should one config
>> hbase to enable this feature in hbase?
>>=20
>> Thanks
>> Yun
>=20