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From "Jonathan Gray (JIRA)" <j...@apache.org>
Subject [jira] Created: (HBASE-802) RowResult containing or supporting more flexible data structures to access elements returned
Date Fri, 08 Aug 2008 17:19:44 GMT
RowResult containing or supporting more flexible data structures to access elements returned
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                 Key: HBASE-802
                 URL: https://issues.apache.org/jira/browse/HBASE-802
             Project: Hadoop HBase
          Issue Type: New Feature
          Components: io
    Affects Versions: 0.2.0
            Reporter: Jonathan Gray
             Fix For: 0.3.0


Extracting actual data from a RowResult can be an ugly process when you don't know what you're
looking for (to be able to query the Map).

For example, if i want to get all columns in a family, or I pass a large number of columns
each of which may or may not exist in the specified row, I need to go through the entire list
of column/Cells.  Currently this is done with something like:

RowResult result = HTable.getRow(rowkey,columns)
Set<Map.Entry<byte [], Cell>> cols = result.entrySet();

>From here I know how many entries are in the Set (cols.size()), but if I want to go through
them, this requires another step change the Set into an Array or an Iterator.

Iterator<Map.Entry<byte [], Cell>> iterator = cols.iterator();
or
Map.Entry<byte [], Cell> [] entries = cols.toArray(new RowResult.Entry[0])

So going from what is returned from HBase, into something usable by the client, requires at
least two additional lines and data structure conversions.  The Map -> Set<Map.Entry>
is very likely to be fast.  I'm unsure about the speed of the Iterator or toArray.  I would
guess that the change to Iterator is fairly efficient (not requiring a copy of the memory),
whereas toArray likely does.

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