Translate IN predicate to connector expression - continue

[assaf2]

Description

Adds translation for InPredicate and InListExpression to connector expression form.

Is this change a fix, improvement, new feature, refactoring, or other?

New feature.

Is this a change to the core query engine, a connector, client library, or the SPI interfaces? (be specific)

Core engine & postgres connector.

How would you describe this change to a non-technical end user or system administrator?

This enabled pushdown of IN predicates which are not expressible with Domain (i.e. references other symbols or contains function calls)

Related issues, pull requests, and links

Documentation

(x) No documentation is needed.
( ) Sufficient documentation is included in this PR.
( ) Documentation PR is available with #prnumber.
( ) Documentation issue #issuenumber is filed, and can be handled later.

Release notes

( ) No release notes entries required.
(x) Release notes entries required with the following suggested text:

# PostgreSQL connector
* Improve performance of queries involving `IN` expression by pushing predicate computation to the PostgreSQL database. (`#13136`)

[assaf2]

I've asked @wendigo to take over his PR #11396.
I've dropped "Rewrite typed NULL char/varchar constants" as @findepi suggested.
I've also dropped "Add explicit cast pushdown support to PostgreSQL" since it now seems to me non-mandatory to the PR and #11396 (comment) is a significant problem. I believe there might be more problematic use cases so IMO should be done on a separate PR.
I've addressed #11396 (comment).

[findepi]

@assaf2 @wendigo is it supposed to supersede #11396?

[findepi]

@assaf2 @wendigo is it supposed to supersede #11396?

thanks for 👍 on that question, @wendigo .

[assaf2]

@assaf2 @wendigo is it supposed to supersede #11396?

IMO yes, the dropped commits:

• "Rewrite typed NULL char/varchar constants"
• "Add explicit cast pushdown support to PostgreSQL"

can be fixed and re-added on a separated PR, if @wendigo thinks they are still necessary

[findepi]

thank you @wendigo @assaf2