Horton

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

Alexander Korotkov <aekorotkov@gmail.com>

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From: Alexander Korotkov <aekorotkov@gmail.com>
To: Alena Rybakina <a.rybakina@postgrespro.ru>
Cc: Andrei Lepikhov <a.lepikhov@postgrespro.ru>, pgsql-hackers@postgresql.org, Peter Geoghegan <pg@bowt.ie>, Robert Haas <robertmhaas@gmail.com>, "Finnerty, Jim" <jfinnert@amazon.com>, Marcos Pegoraro <marcos@f10.com.br>, teodor@sigaev.ru, Ranier Vilela <ranier.vf@gmail.com>, Tomas Vondra <tomas.vondra@enterprisedb.com>, Peter Eisentraut <peter@eisentraut.org>
Date: 2023-11-25T01:23:38Z
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 Fri, Nov 24, 2023 at 7:05 AM Alena Rybakina
<a.rybakina@postgrespro.ru> wrote:
> On 23.11.2023 12:23, Andrei Lepikhov wrote:
> > I think the usage of nodeToString for the generation of clause hash is
> > too expensive and buggy.
> > Also, in the code, you didn't resolve hash collisions. So, I've
> > rewritten the patch a bit (see the attachment).
> > One more thing: I propose to enable transformation by default at least
> > for quick detection of possible issues.
> > This code changes tests in many places. But, as I see it, it mostly
> > demonstrates the positive effect of the transformation.
>
> On 24.11.2023 06:30, Andrei Lepikhov wrote:
>
> > On 23/11/2023 16:23, Andrei Lepikhov wrote:
> >> This code changes tests in many places. But, as I see it, it mostly
> >> demonstrates the positive effect of the transformation.
> >
> > I found out that the postgres_fdw tests were impacted by the feature.
> > Fix it, because the patch is on the commitfest and passes buildfarm.
> > Taking advantage of this, I suppressed the expression evaluation
> > procedure to make regression test changes more clear.
>
> Thank you for your work. You are right, the patch with the current
> changes looks better and works more correctly.
>
> To be honest, I didn't think we could use JumbleExpr in this way.

I think patch certainly gets better in this aspect.  One thing I can't
understand is why do we use home-grown code for resolving
hash-collisions.  You can just define custom hash and match functions
in HASHCTL.  Even if we need to avoid repeated JumbleExpr calls, we
still can save pre-calculated hash value into hash entry and use
custom hash and match.  This doesn't imply us to write our own
collision-resolving code.

------
Regards,
Alexander Korotkov