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From David Medinets <david.medin...@gmail.com>
Subject Re: Could combiners be coded using groovy?
Date Sat, 19 May 2012 21:57:04 GMT
I finally got a chance to try your suggestion. But I'm confused
because the semantics of a TreeMap seem different from those of
Accumulo. For example, here I insert some data into the TreeMap:

		TreeMap<Key, Value> tm = new TreeMap<Key, Value>();
		Key key = new Key(new Text("row"), new Text("cf"), new Text("cq"),
new Text(""));
		Value value = new Value("13".getBytes());
		tm.put(key, value);
		
		key = new Key(new Text("row"), new Text("cf"), new Text("cq"), new Text(""));
		value = new Value("14".getBytes());
		tm.put(key, value);
		
		key = new Key(new Text("row"), new Text("cf"), new Text("cq"), new Text(""));
		value = new Value("15".getBytes());
		tm.put(key, value);

And then I try to use a SummingCombiner which I have used successfully
against Accumulo. Here is that code:

		Map<String,String> options = new HashMap<String, String>();
		options.put("type", "STRING");
		
		SummingCombiner iter = new SummingCombiner();

		IteratorSetting is = new IteratorSetting(1, SummingCombiner.class, options);
		Combiner.setCombineAllColumns(is, true);

		iter.init(new SortedMapIterator(tm), is.getOptions(), null);
		iter.seek(new Range(), new ArrayList<ByteSequence>(), false);

		while (iter.hasTop()) {
			Key k = iter.getTopKey();
			Value v = iter.getTopValue();
			System.out.println("K: " + k + "  V: " + v);
			iter.next();
		}
		System.out.println("END");

Here is the output:

START
K: row cf:cq [] 9223372036854775807 false  V: 15
END

The SummingCombiner is only seeing one record which makes sense since
the keys overwrite each other in the TreeMap. Am I missing something?

On Tue, Apr 10, 2012 at 3:57 PM, Billie J Rinaldi
<billie.j.rinaldi@ugov.gov> wrote:
> I'm not familiar with Groovy, but it sounds interesting.  I could recommend some ways
to test your iterator before you push it out to Accumulo.  You can make some fake data for
a unit test by creating a TreeMap<Key,Value> and then using a SortedMapIterator to turn
that into a source for your iterator.  A lot of our unit tests look like the following.
>
>  TreeMap<Key,Value> tm = new TreeMap<Key,Value>();
>  // put some data into the tree map
>
>  MyIterator iter = new MyIterator();
>
>  IteratorSetting is = new IteratorSetting(1, MyIterator.class);
>  MyIterator.setSomeOption(is, option);
>
>  iter.init(new SortedMapIterator(tm), is.getOptions(), null);
>  iter.seek(new Range(), new ArrayList<ByteSequence>(), false);
>
>  while (iter.hasTop()) {
>    Key k = iter.getTopKey();
>    Value v = iter.getTopValue();
>    // check that k and v are what you expected
>    iter.next();
>  }
>
> Another option is to use the ClientSideIteratorScanner to test your iterator in your
local JVM before running it on a tserver.
>
> Billie
>
>
> On Sunday, April 8, 2012 11:08:05 PM, "David Medinets" <david.medinets@gmail.com>
wrote:
>> I was working with combiners and seeing the jar file loaded and
>> reloaded. And seeing my accumulo crash because I coded the combiner
>> incorrectly. I started to wonder how easier it might be to easy a
>> dynamically compiled language like Groovy to developer combiners.
>>
>> How hard would it be to integrate Groovy? Have any of the core
>> accumulo developers used groovy?
>>
>> Is there a better language than groovy now? I last worked with groovy
>> #$%$ years ago. It worked very well for me.

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