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HBase >> mail # user >> Put w/ timestamp -> Deleteall -> Put w/ timestamp fails


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Re: Put w/ timestamp -> Deleteall -> Put w/ timestamp fails
When a Delete occurs, an insert is made with the timestamp being the
current time (to indicate it is the latest version). Hence, when you
insert a value after this with an _older_ timestamp, it is not taken
in as the latest version, and is hence ignored when scanning. This is
why you do not see the data.

If you instead insert this after a compaction has fully run on this
store file, then your value will indeed get shown after insert, cause
at that moment there wouldn't exist such a row with a latest timestamp
at all.

hbase(main):060:0> flush 'test-table'
0 row(s) in 0.1020 seconds

hbase(main):061:0> major_compact 'test-table'
0 row(s) in 0.0400 seconds

hbase(main):062:0> put 'test-table', 'row4', 'test-family', 'value', 10
0 row(s) in 0.0230 seconds

hbase(main):063:0> scan 'test-table'
ROW                   COLUMN+CELL
 row4                 column=test-family:, timestamp=10, value=value
1 row(s) in 0.0060 seconds

I suppose this is why it is recommended not to mess with the
timestamps manually, and instead just rely on versions.

On Tue, Aug 14, 2012 at 8:24 PM, Takahiko Kawasaki <[EMAIL PROTECTED]> wrote:
> Hello,
>
> I have a problem where 'put' with timestamp does not succeed.
> I did the following at the HBase shell.
>
> (1) Do 'put' with timestamp.
>       # 'scan' shows 1 row.
>
> (2) Delete the row by 'deleteall'.
>       # 'scan' says "0 row(s)".
>
> (3) Do 'put' again by the same command line as (1).
>       # 'scan' says "0 row(s)" ! Why?
>
> (4) Increment the timestamp value by 1 and try 'put' again.
>       # 'scan' still says "0 row(s)"! Why?
>
> The command lines I actually typed are as follows and the attached
> file is the output from the command lines.
>
> scan 'test-table'
> put 'test-table', 'row3', 'test-family', 'value'
> scan 'test-table'
> deleteall 'test-table', 'row3'
> scan 'test-table'
> put 'test-table', 'row3', 'test-family', 'value'
> scan 'test-table'
> deleteall 'test-table', 'row3'
> scan 'test-table'
> put 'test-table', 'row4', 'test-family', 'value', 10
> scan 'test-table'
> deleteall 'test-table', 'row4'
> scan 'test-table'
> put 'test-table', 'row4', 'test-family', 'value', 10
> scan 'test-table'
> put 'test-table', 'row4', 'test-family', 'value', 10
> scan 'test-table'
> quit
>
> Is this behavior the HBase specification?
>
> My cluster is built using CDH4 and the HBase version is 0.92.1-cdh4.0.0.
>
> Could anyone give me any insight, please?
>
> Best Regards,
> Takahiko Kawasaki

--
Harsh J
NEW: Monitor These Apps!
elasticsearch, apache solr, apache hbase, hadoop, redis, casssandra, amazon cloudwatch, mysql, memcached, apache kafka, apache zookeeper, apache storm, ubuntu, centOS, red hat, debian, puppet labs, java, senseiDB