[geomesa-users] Scanning some particular index

[Serge Vilvovsky <sergevil@xxxxxxxxx>]

Hi,

I need to scan a secondary index and see the list of primary Ids. 

I started with geotable example by adding index=full for "What" attibute.

        // list the attributes that constitute the feature type
        List<String> attributes = Lists.newArrayList(
                "Who:String:index=full",
                "What:java.lang.Long:index=full",     // some types require full qualification (see DataUtilities docs)
                "When:Date",               // a date-time field is optional, but can be indexed
                "*Where:Point:srid=4326",  // the "*" denotes the default geometry (used for indexing)
                "Why:String"               // you may have as many other attributes as you like...
        );

What I need is by scanning 'What' index to receive the sorted List of pairs (What, Primary Feature Id)

For my understanding the fastest way to do it is just scanning directly the index table and finding the feature Id instead of scanning the index and seeking whole the feature at the records table. But may be the whole feature is encoded at the index table, so it does not require seeking in records table. 

For two features I see the next rows:

root@singlenode> scan -t geotable_attr_idx

\x01\x00\x00Addams\x0080000148368cObservation.0 : []    \x02\x00\x00\x00=Observation.\xB0Addam\xF3\x01\x00\x00\x00\x00\x00\x00\x00\x00\x01\x00\x00\x01H6\x8C\xF3\x00\x01\x01\xC0S\x03\xB1\xD6N4\xB6\xC0B\xCE\xD8n\x884\xE0\x80\x12\x18!*<

\x01\x00\x00Bierce\x00800001456f2aObservation.1 : []    \x02\x00\x00\x00=Observation.\xB1Bierc\xE5\x01\x00\x00\x00\x00\x00\x00\x00\x01\x01\x00\x00\x01Eo*\xE7\xB0\x01\x01\xC0S_\x053\xD3\x90%\xC0Co\xE8 Z\xB1>\x80\x12\x18!*<

\x01\x00\x018000000000000000\x0080000148368cObservation.0 : []    \x02\x00\x00\x00=Observation.\xB0Addam\xF3\x01\x00\x00\x00\x00\x00\x00\x00\x00\x01\x00\x00\x01H6\x8C\xF3\x00\x01\x01\xC0S\x03\xB1\xD6N4\xB6\xC0B\xCE\xD8n\x884\xE0\x80\x12\x18!*<

\x01\x00\x018000000000000001\x00800001456f2aObservation.1 : []    \x02\x00\x00\x00=Observation.\xB1Bierc\xE5\x01\x00\x00\x00\x00\x00\x00\x00\x01\x01\x00\x00\x01Eo*\xE7\xB0\x01\x01\xC0S_\x053\xD3\x90%\xC0Co\xE8 Z\xB1>\x80\x12\x18!*<

My questions are:

1. Is it any efficient top level API that I can use?

If not:

2. Am I looking at the right table?

3. How to scan the rows to ignore the Who index and use only What index?

4. How to decode the received rows?

Thank you!

Serge