Horton

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

Andrei Lepikhov <a.lepikhov@postgrespro.ru>

View thread
From: Andrei Lepikhov <a.lepikhov@postgrespro.ru>
To: Alexander Korotkov <aekorotkov@gmail.com>, Alena Rybakina <a.rybakina@postgrespro.ru>
Cc: Nikolay Shaplov <dhyan@nataraj.su>, pgsql-hackers@lists.postgresql.org, jian he <jian.universality@gmail.com>, Robert Haas <robertmhaas@gmail.com>, pgsql-hackers@postgresql.org, Peter Geoghegan <pg@bowt.ie>, Marcos Pegoraro <marcos@f10.com.br>, teodor@sigaev.ru, Tomas Vondra <tomas.vondra@enterprisedb.com>, Peter Eisentraut <peter@eisentraut.org>, Ranier Vilela <ranier.vf@gmail.com>
Date: 2024-08-21T13:08:14Z
Lists: pgsql-hackers

Commits

Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →

  1. Make group_similar_or_args() reorder clause list as little as possible

  2. Allow usage of match_orclause_to_indexcol() for joins

  3. Skip not SOAP-supported indexes while transforming an OR clause into SAOP

  4. Remove the wrong assertion from match_orclause_to_indexcol()

  5. Teach bitmap path generation about transforming OR-clauses to SAOP's

  6. Transform OR-clauses to SAOP's during index matching

  7. Fix the value of or_to_any_transform_limit in postgresql.conf.sample

  8. Transform OR clauses to ANY expression

  9. MergeAttributes code deduplication

  10. SEARCH and CYCLE clauses

  11. Improve estimation of OR clauses using extended statistics.

  12. Teach btree to handle ScalarArrayOpExpr quals natively.

  13. Revise collation derivation method and expression-tree representation.

  14. Instead of trying to force WHERE clauses into CNF or DNF normal form,

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