[HIVE-4377] Add more comment to https://reviews.facebook.net/D1209 (HIVE-2340)

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 0.12.0
• Component/s: Query Processor
• Assignee: Navis Ryu
• Reporter: Gang Tim Liu
• Created: 18/Apr/13 15:36
• Updated: 15/Oct/13 23:29
• Resolved: 04/Jun/13 13:28

Description

thanks a lot for addressing optimization in HIVE-2340. Awesome!

Since we are developing at a very fast pace, it would be really useful to
think about maintainability and testing of the large codebase. Highlights which are applicable for D1209:

1. Javadoc for all public/private functions, except for
setters/getters. For any complex function, clear examples (input/output)
would really help.
2. Specially, for query optimizations, it might be a good idea to have
a simple working query at the top, and the expected changes. For e.g..
The operator tree for that query at each step, or a detailed explanation
at the top.
3. If possible, the test name (.q file) where the function is being
invoked, or the query which would potentially test that scenario, if it
is a query processor change.
4. Comments in each test (.q file)­ that should include the jira
number, what is it trying to test. Assumptions about each query.
5. Reduce the output for each test ­ whenever query is outputting more
than 10 results, it should have a reason. Otherwise, each query result
should be bounded by 10 rows.

thanks a lot