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From "Niels Basjes (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (HBASE-11990) Make setting the start and stop row for a specific prefix easier
Date Sun, 21 Sep 2014 22:18:34 GMT

    [ https://issues.apache.org/jira/browse/HBASE-11990?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14142744#comment-14142744
] 

Niels Basjes commented on HBASE-11990:
--------------------------------------

The superclass filter is the logical AND of the setFilter and the setRowPrefixFilter. 
Each time you set either one of them this logical AND must be recalculated.
The userFilter stores the value of setFilter which is in general different than this logical
AND.

Now you can also 'unset' either one of them by calling the setter with 'null' (this is part
of the unit tests) and still get the correct result.

> Make setting the start and stop row for a specific prefix easier
> ----------------------------------------------------------------
>
>                 Key: HBASE-11990
>                 URL: https://issues.apache.org/jira/browse/HBASE-11990
>             Project: HBase
>          Issue Type: New Feature
>          Components: Client
>            Reporter: Niels Basjes
>         Attachments: 11990v4.txt, HBASE-11990-20140916-v2.patch, HBASE-11990-20140916-v3.patch,
HBASE-11990-20140916-v5.patch, HBASE-11990-20140916-v6.patch, HBASE-11990-20140916.patch,
HBASE-11990-20140917-v7.patch, HBASE-11990-20140919-v8.patch, HBASE-11990-20140921-v9.patch
>
>
> If you want to set a scan from your application to scan for a specific row prefix this
is actually quite hard.
> As described in several places you can set the startRow to the prefix; yet the stopRow
should be set to the prefix '+1'
> If the prefix 'ASCII' put into a byte[] then this is easy because you can simply increment
the last byte of the array. 
> But if your application uses real binary rowids you may run into the scenario that your
prefix is something like 
> {code}{ 0x12, 0x23, 0xFF, 0xFF }{code} Then the increment should be {code}{ 0x12, 0x24
}{code}
> I have prepared a proposed patch that makes setting these values correctly a lot easier.



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