02/07/08
--------

Summary
- Additional "DBIndex" in jsd
- Performance of GROUP BY and ORDER BY
- Documentation

Additional "DBIndex" in jsd
----------------------------

Added a "DBIndex" line in jsd that specifies keywords to be made into
indices. Each keyword on the list is made into an index in
create_series. I have not yet removed the composite index for DRMS
prime key. I will postpone that until I finish the performance test
for GROUP BY and ORDER BY.

Performance of GROUP BY and ORDER BY
-------------------------------------
GROUP BY is used to select the lastest record. ORDER BY is used to
sort. Both are based on DRMS prime key.

I read about GROUP BY and ORDER BY from PostgreSQL documentation.

I prepared performance test for group by and order by with/without
indices. This is going to help us to decide what to do with the DRMS
prime keys.

Test data source from Rick: /scr/rick/tilelist.9d
It has about 65952 records.

Documentation
-------------

So far in the style of stream of consciousness, covering many topics
that I have learned over the past year about DRMS. In addition to an
overview, I am adding some in-depth topics like the following: 
- How/when does a record get committed to the database
- How to stage a SU (other than show_keys -p)
- Series/segment/record caching
- The exiting procedure
- DRMS communication with SUMS (blocking vs non-blocking alternatives)
- Concurrent access control in drms_server
- ...

For each topics, I list both do's and dont's. Let me know if you have
any suggestions.