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From "stack (JIRA)" <j...@apache.org>
Subject [jira] Commented: (HBASE-605) allow scanners which return results ordred by a column value
Date Thu, 22 May 2008 19:53:56 GMT

    [ https://issues.apache.org/jira/browse/HBASE-605?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12599164#action_12599164

stack commented on HBASE-605:

Unfortunately, we're still java5.  We probably won't go to java6 as a requirement until hbase
0.3, to match hadoop 0.18.  Please purge the java6isms (NavigableSet in SortedColumn).

Also, I get this compiling:

    [javac] /Users/stack/Documents/checkouts/trunk/src/java/org/apache/hadoop/hbase/LocalHBaseCluster.java:121:
cannot find symbol
    [javac] symbol  : constructor IOException(java.lang.Exception)
    [javac] location: class java.io.IOException
    [javac]         throw new IOException(e);

Do you?

Thanks Clint (I already updated the FAQ to point to OrderedRegionServer as example modifying
HRegionServer behavior).

> allow scanners which return results ordred by a column value
> ------------------------------------------------------------
>                 Key: HBASE-605
>                 URL: https://issues.apache.org/jira/browse/HBASE-605
>             Project: Hadoop HBase
>          Issue Type: New Feature
>          Components: client, regionserver
>    Affects Versions: 0.2.0
>            Reporter: Clint Morgan
>            Priority: Minor
>         Attachments: hbase-605-v2.patch, hbase-605-v3.patch, hbase-605.patch
> We would like to be able to scan though tables with results ordered by (deserialized)
column values. This approach maintains an in-memory sorted set for each ordered-by column
in each HStore. This allows us to iterate through the keys in column order, and to random
reads on the key to get the full row.
> Without the index, then we have to scan through all the rows to get the first result
ordered by a column. Thus, when R is the number of rows in a table,  N is the number of ordered-by
rows we want, and R >> N we can save a lot of work by not doing the full table scan.

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