Re: POC, WIP: OR-clause support for indexes

On 21/8/2024 02:17, Alexander Korotkov wrote:
> Also, I convert the check you've introduced in the previous message to
> op_in_opfamily(), and introduced collation check similar to
> match_opclause_to_indexcol().
Hi,
I passed through the patches with fresh sight. Conceptually, this 
approach looks much better than the previous series.
Just for the record: previously, we attempted to resolve two issues in 
one - improve the execution plan and save cycles during the 
optimisation. As I see it, it is almost impossible in this feature. So, 
I should come to terms with carrying long OR lists through the planning 
and the additional overhead this feature generates.
I also see that the optimiser has obtained additional planning 
strategies with these patches and hasn't lost any.

Couple of findings:

First:
/* Only operator clauses scan match */
Should it be:
/* Only operator clauses can match */
?
The second one:
When creating IndexClause, we assign the original and derived clauses to 
the new, containing transformed array. But logically, we should set the 
clause with a list of ORs as the original. Why did you do so?

-- 
regards,
Andrei Lepikhov
Postgres Professional