some tests with Composite (Composite as column names=>OK, as row keys=>KO)

[DE VITO Dominique <do...@thalesgroup.com>]

Hi,

I have tried few experiments with Composite (first, as columns, and next, as rows).
I have followed the paths described by http://www.datastax.com/dev/blog/introduction-to-composite-columns-part-1

My composite is (UTF8, UTF8): (folderId, filename)
And I have inserted for all tests, the following data: ("FID", "AT2"), ("FID", "BT2")... ("FID", "FT2")... ("FID", "ZT2")

I am using Hector + Cassandra 1.0.7
with the ByteOrderedPartitioner

a) using a Composite for column names
See [a] for the CF definition, and the algorithms used.

All data is into 1 row, named "1", including all the columns with the following Composite names: ("FID", "AT2"), ("FID", "BT2")... ("FID", "FT2")... ("FID", "ZT2")
I wanted to get only filenames (2nd component of the Composite) starting with "FT".
If the algorithm is correct, I should get one single result "FT2".

I have used a SliceQuery following the DataStax algo above: just OK
I have used too a RangeSlicesQuery following the DataStax algo above: just OK
For both cases, I have got only one result: "FT2".
Perfect.

b) using a Composite for row keys
See [b] for the CF definition, and the algorithms used.

All data are in rows with the following Composite row keys: ("FID", "AT2"), ("FID", "BT2")... ("FID", "FT2")... ("FID", "ZT2")
I wanted to get only filenames (2nd component of the Composite) starting with "FT".
If the algorithm is correct, I should get one single result "FT2".

I have used a RangeSlicesQuery following the DataStax algo above: KO
Instead of getting a single result "FT2", I have got 6 items: "AT2", "BT2", "CT2", "DT2", "ET2", "FT2"

Well, I am still wondering why I didn't get the same result for Composite as row keys than Composite as column names.

Is anyone having an idea ?
and a solution for fetching all the rows with a key like ("FID", "FT*") - that is, the 1st component is fixed "FID", and the 2nd component is expected to start with "FT" ?

Thanks.

Regards,
Dominique

[a]
create column family CF_COL with
                comparator='CompositeType(UTF8Type, UTF8Type)' and
                default_validation_class=UTF8Type and
                key_validation_class=UTF8Type;

[a.1] using SliceQuery

SliceQuery<String, Composite, String> q = hector.createSliceQuery(getKeyspace(),
                                                                      stringSerializer,
                                                                      new CompositeSerializer(),
                                                                      stringSerializer);
q.setColumnFamily("CF_COL");
Composite startRange = new Composite();
startRange.addComponent(0, "FID", AbstractComposite.ComponentEquality.EQUAL);
startRange.addComponent(1, "FT", AbstractComposite.ComponentEquality.EQUAL);

Composite endRange = new Composite();
endRange.addComponent(0, "FID", AbstractComposite.ComponentEquality.EQUAL);
endRange.addComponent(1,
                          "FT" + Character.MAX_VALUE,
                          AbstractComposite.ComponentEquality.GREATER_THAN_EQUAL);

q.setKey("1");
q.setRange(startRange, endRange, false, 1000);

[a.2] using RangeSlicesQuery

RangeSlicesQuery<String, Composite, String> q = hector.createRangeSlicesQuery(getKeyspace(),
                                                                                  stringSerializer,
                                                                                  new CompositeSerializer(),
                                                                                  stringSerializer);
q.setColumnFamily("CF_COL");
Composite startRange = new Composite();
startRange.addComponent(0, "FID", AbstractComposite.ComponentEquality.EQUAL);
startRange.addComponent(1, "FT", AbstractComposite.ComponentEquality.EQUAL);

Composite endRange = new Composite();
endRange.addComponent(0, "FID", AbstractComposite.ComponentEquality.EQUAL);
endRange.addComponent(1,
                          "FT" + Character.MAX_VALUE,
                          AbstractComposite.ComponentEquality.GREATER_THAN_EQUAL);

q.setKeys("1", "1");
q.setRange(startRange, endRange, false, 1000);
q.setRowCount(1);

[b]
create column family CF_ROW with
                comparator=UTF8Type and
                default_validation_class=UTF8Type and
                key_validation_class='CompositeType(UTF8Type, UTF8Type)';

RangeSlicesQuery<Composite, String, String> q = hector.createRangeSlicesQuery(getKeyspace(),
                                                                                  new CompositeSerializer(),
                                                                                  stringSerializer,
                                                                                  stringSerializer);
q.setColumnFamily("CF_ROW");
Composite startRange = new Composite();
startRange.addComponent(0, "FID", AbstractComposite.ComponentEquality.EQUAL);
startRange.addComponent(1, "FT", AbstractComposite.ComponentEquality.EQUAL);

Composite endRange = new Composite();
endRange.addComponent(0, "FID", AbstractComposite.ComponentEquality.EQUAL);
endRange.addComponent(1,
                          "FT" + Character.MAX_VALUE,
                          AbstractComposite.ComponentEquality.GREATER_THAN_EQUAL);

q.setKeys(startRange, endRange);
q.setReturnKeysOnly();
q.setRowCount(1000);