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HBase >> mail # user >> How to config hbase0.94.2 to retain deleted data


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yun peng 2012-10-21, 20:53
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Re: How to config hbase0.94.2 to retain deleted data
I would suggest that you use your coprocessor to copy the data to a 'backup' table when you mark them for delete.
Then as major compaction hits, the rows are deleted from the main table, but still reside undeleted in your delete table.
Call it a history table.
On Oct 21, 2012, at 3:53 PM, yun peng <[EMAIL PROTECTED]> wrote:

> 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.
>
>  public void postOpen(ObserverContext<RegionCoprocessorEnvironment> e) {
>    HTableDescriptor htd = e.getEnvironment().getRegion().getTableDesc();
>    HColumnDescriptor hcd = htd.getFamily(Bytes.toBytes("cf"));
>    hcd.setKeepDeletedCells(true);
>    hcd.setBlockCacheEnabled(false);
>  }
>
> However, it does not work for me, as when I issued a delete and then query
> by an older timestamp, the old data does not show up.
>
> 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 => 'cf:c1', TIMESTAMP
> => 99, VERSIONS => 4}
> COLUMN                CELL
>
> 0 row(s) in 0.0040 seconds
>
> hbase(main):123:0> get 'usertable', 'key1', {COLUMN => 'cf:c1', TIMESTAMP
> => 100, VERSIONS => 4}
> COLUMN                CELL
>
> 0 row(s) in 0.0050 seconds
>
> hbase(main):124:0> get 'usertable', 'key1', {COLUMN => 'cf:c1', TIMESTAMP
> => 101, VERSIONS => 4}
> COLUMN                CELL
>
> cf:c1                timestamp=101, value=v2
>
> 1 row(s) in 0.0050 seconds
>
> 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?
>
> Thanks
> Yun
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lars hofhansl 2012-10-22, 00:23
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Michael Segel 2012-10-22, 01:56
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Michael Segel 2012-10-23, 04:18
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lars hofhansl 2012-10-23, 05:22
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Michael Segel 2012-10-23, 11:41
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lars hofhansl 2012-10-23, 18:35
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Michael Segel 2012-10-23, 18:40
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lars hofhansl 2012-10-23, 18:47
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Marcos Ortiz Valmaseda 2012-10-22, 02:12
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lars hofhansl 2012-10-21, 23:04
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yun peng 2012-10-22, 00:20
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lars hofhansl 2012-10-22, 04:34
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PG 2012-10-23, 22:01