Re: Making Vars outer-join aware

Finnerty, Jim <jfinnert@amazon.com>

From: "Finnerty, Jim" <jfinnert@amazon.com>

To: Tom Lane <tgl@sss.pgh.pa.us>, "pgsql-hackers@lists.postgresql.org" <pgsql-hackers@lists.postgresql.org>

Date: 2022-07-01T20:19:48Z

Lists: pgsql-hackers

Commits

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Re-allow INDEX_VAR as rt_index in ChangeVarNodes().
- fbf80421ead5 16.0 landed
Fix thinkos in have_unsafe_outer_join_ref; reduce to Assert check.
- f50f029c497d 16.0 landed
Invent "join domains" to replace the below_outer_join hack.
- 3bef56e11650 16.0 landed
Do assorted mop-up in the planner.
- b448f1c8d83f 16.0 landed
Make Vars be outer-join-aware.
- 2489d76c4906 16.0 landed
Invent "multibitmapsets", and use them to speed up antijoin detection.
- e9e26b5e7166 16.0 landed
Add basic regression tests for semi/antijoin recognition.
- 0043aa6b8597 16.0 landed
Improve performance of adjust_appendrel_attrs_multilevel.
- 2f17b57017e5 16.0 landed
Refactor addition of PlaceHolderVars to joinrel targetlists.
- afa0ec30bfd1 16.0 landed
Use an explicit state flag to control PlaceHolderInfo creation.
- b3ff6c742f6c 16.0 landed
Make PlaceHolderInfo lookup O(1).
- 6569ca43973b 16.0 landed

Tom, two quick questions before attempting to read the patch:

    Given that views are represented in a parsed representation, does anything need to happen to the Vars inside a view when that view is outer-joined to?  

    If an outer join is converted to an inner join, must this information get propagated to all the affected Vars, potentially across query block levels?