Horton

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

Robert Haas <robertmhaas@gmail.com>

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From: Robert Haas <robertmhaas@gmail.com>
To: Peter Geoghegan <pg@bowt.ie>
Cc: Alexander Korotkov <aekorotkov@gmail.com>, Tom Lane <tgl@sss.pgh.pa.us>, Alena Rybakina <a.rybakina@postgrespro.ru>, jian he <jian.universality@gmail.com>, Nikolay Shaplov <dhyan@nataraj.su>, pgsql-hackers@lists.postgresql.org, pgsql-hackers@postgresql.org, Marcos Pegoraro <marcos@f10.com.br>, teodor@sigaev.ru, Peter Eisentraut <peter@eisentraut.org>, Ranier Vilela <ranier.vf@gmail.com>, Andrei Lepikhov <lepihov@gmail.com>
Date: 2024-10-04T12:31:02Z
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 Thu, Oct 3, 2024 at 4:15 PM Peter Geoghegan <pg@bowt.ie> wrote:
> Now that you're explicitly creating RestrictInfos for a particular
> index, I suppose that it might be easier to do this kind of thing --
> you have more context. Perhaps the patch can be made to recognize
> a mix of constants like this as all being associated with the same
> B-Tree operator family (the opfamily that the input opclass belongs
> to)? Perhaps the constants could all be normalized to the same type via
> casts/coercions into the underlying B-Tree input opclass -- that
> extra step should be correct ("64.1.2. Behavior of B-Tree Operator Classes"
> describes certain existing guarantees that this step would need to rely
> on).

I don't think you can convert everything to the same type because we
have to assume that type conversions can fail. An exception is if the
types are binary-compatible but that's not the case here. If there's a
way to fix this problem, it's probably by doing the first thing you
suggest above: noticing that all the constants belong to the same
opfamily. I'm not sure if that approach can work either, but I think
it has better chances.

Personally, I don't think this particular limitation is a problem. I
don't think it will be terribly frequent in practice, and it doesn't
seem any weirder than any of the other things that happen as a result
of small and large integer constants being differently typed.

-- 
Robert Haas
EDB: http://www.enterprisedb.com