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HBase, mail # user - Where is code in hbase that physically delete a record?


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Re: Where is code in hbase that physically delete a record?
yun peng 2012-10-17, 15:34
Hi, Ram and Anoop, Thanks for the nice reference on the java file, which I
will check through.

It is interesting to know about the recent feature on
preCompactScannerOpen() hook. Ram, it would be nice if I can know how to
specify conditions like c1 = 'a'.  I have also checked the example code in
hbase 6496 link <https://issues.apache.org/jira/browse/HBASE-6496>. which
show how to delete data before time as in a on-demand specification...
Cheers,
Yun

On Wed, Oct 17, 2012 at 8:46 AM, Ramkrishna.S.Vasudevan <
[EMAIL PROTECTED]> wrote:

> Also to see the code how the delete happens pls refer to StoreScanner.java
> and how the ScanQueryMatcher.match() works.
>
> That is where we decide if any kv has to be avoided due to already deleted
> tombstone marker.
>
> Forgot to tell you about this.
>
> Regards
> Ram
>
> > -----Original Message-----
> > From: yun peng [mailto:[EMAIL PROTECTED]]
> > Sent: Wednesday, October 17, 2012 5:54 PM
> > To: [EMAIL PROTECTED]
> > Subject: Where is code in hbase that physically delete a record?
> >
> > Hi, All,
> > I want to find internal code in hbase where physical deleting a record
> > occurs.
> >
> > -some of my understanding.
> > Correct me if I am wrong. (It is largely based on my experience and
> > even
> > speculation.) Logically deleting a KeyValue data in hbase is performed
> > by
> > marking tombmarker (by Delete() per records) or setting TTL/max_version
> > (per Store). After these actions, however, the physical data are still
> > there, somewhere in the system. Physically deleting a record in hbase
> > is
> > realised by *a scanner to discard a keyvalue data record* during the
> > major_compact.
> >
> > -what I need
> > I want to extend hbase to associate some actions with physically
> > deleting a
> > record. Does hbase provide such hook (or coprocessor API) to inject
> > code
> > for each KV record that is skipped by hbase storescanner in
> > major_compact.
> > If not, anyone knows where should I look into in hbase (-0.94.2) for
> > such
> > code modification?
> >
> > Thanks.
> > Yun
>
>