Github user jihoonson commented on the pull request:
https://github.com/apache/tajo/pull/441#issuecomment-84362382
@navis thanks for your work. This will be definitely useful.
However, it seems that the title sould be changed. I think that you already
know, but would like to explain for clarity.
In Tajo, there are three planning phases, i.e., logical planning phase,
global planning phase, and physical planning phase. When a query is submitted,
the logical planner generates a logical plan based on the query. And then, the
global planner generates a master plan that explains how the query is executed
in distributed manner. Once the master plan is generated, the query master
executes execution blocks of that master plan subsequently.
An execution block is executed by multiple workers. For distributed
execution, each worker receives the logical plan corresponds to the currently
executing execution block. Finally, a worker generates a physical plan based on
the received logical plan. It indicates which types of physical operators are
used to execute the logical plan. For example, given a logical plan for join,
the physical plan indicates that the hash join or sorted-merge join will be
used.
Your work seems to see the the master (global) plan. So, it would be better
to change the title.
Anyway, I'm still reviewing. I'll finish soon.
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