Re: BUG #17975: Nested Loop Index Scan returning wrong result

On Thu, 15 Jun 2023 at 12:28, Tom Lane  wrote:
> I concur that we'd better just not use partial indexes in
> relation_has_unique_index_for.

I wonder if that's ok for a backpatch.  This affects both left join
removals and unique joins.  Seems like suddenly making a left join
removal not work might cause someone some pain.

Is it worth trying to jam in a new boolean field into IndexOptInfo
into some spare padding to that we run predicate_implied_by() just
using baserestrictinfo and use those in
relation_has_unique_index_for()?

One problem might be that I don't see anywhere we could jam another
boolean into IndexOptInfo on 32-bit builds. Maybe we could put it at
the end given that we should only be making these structs in core?

David