> After that, I'll implement PATH and CLASSIFIER functions, which depend on
> having
> the match context available.
What is PATH function? It's not in R010 or R020 as far as I know.
A Match Path is essentially an array consisting of the CLASSIFIER() values of all rows
within a matched sequence, arranged in chronological order.
> Longer-term, the goal is to get to MATCH_RECOGNIZE in the FROM clause for
> full SQL standard compliance.
What about MEASURES clause? Without it, many things in the standard
cannot be implemented.
I admit that my current understanding of the full SQL standard is still evolving. However,
looking at the current codebase, I believed that the syntax I've implemented so far
could be addressed even before mastering every detail of the standard.
That is why I have taken a 'code-first' approach for this stage.
Of course, reaching 'FULL' compliance is undoubtedly the ultimate goal. Given
the complexity, I believe the features should be released in several incremental phases.
I trust that you will help define the strategic roadmap for these releases. As I continue to
deepen my understanding of the standard, I will do my best to contribute to the
technical roadmap as well.
> Let me know if you have any concerns or suggestions about the approach.
Here are some comments on your patches.
- It is based on my v36 patches. But the latest one is v37 patch. It
would be nice if you create patches based on the my latest patches.
I will rebase my work on your latest v37 patch and move forward with that
for the next version. I’ll submit the updated patch soon.
- You are doing some optimization (like (A (B C)) gets flattened to (A
B C) etc.) in the parse analysis phase. I think doing that kind of
optimization should be done in the optimizer/planner. Because with
your patch a deparsed query (as shown by pg_get_viewdef()) looks
different from what user inputs.
I completely agree that those optimizations belong in the optimizer/planner phase.
I intentionally placed them in the parse analysis phase for now to make debugging
easier during this initial development stage. Once the logic is stabilized, I will move
them to the planner as you suggested to ensure proper deparsing.
- If you add files to src/backend/parser, it should be noted in
src/backend/parser/README.
- It would be noce to update typedefs patch if you add new typedefs.
Thank you for pointing those out. I had overlooked the README in src/backend/parser,
and I will make sure to update it along with the typedefs patch in my next submission.
Best regards,
Henson
