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

Alena Rybakina <a.rybakina@postgrespro.ru>

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From: Alena Rybakina <a.rybakina@postgrespro.ru>
To: jian he <jian.universality@gmail.com>, Andrei Lepikhov <a.lepikhov@postgrespro.ru>
Cc: Alexander Korotkov <aekorotkov@gmail.com>, Robert Haas <robertmhaas@gmail.com>, pgsql-hackers@postgresql.org, Peter Geoghegan <pg@bowt.ie>, "Finnerty, Jim" <jfinnert@amazon.com>, 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: 2024-02-28T10:27:41Z
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 28.02.2024 13:07, jian he wrote:
> On Wed, Feb 28, 2024 at 12:19 PM Andrei Lepikhov
> <a.lepikhov@postgrespro.ru> wrote:
>> On 26/2/2024 11:10, Alena Rybakina wrote:
>>> On 24.02.2024 14:28, jian he wrote:
>>>> Hi.
>>>> I wrote the first draft patch of the documentation.
>>>> it's under the section: Planner Method Configuration
>>>> (runtime-config-query.html)
>>>> but this feature's main meat is in src/backend/parser/parse_expr.c
>>>> so it may be slightly inconsistent, as mentioned by others.
>>>>
>>>> You can further furnish it.
>>> Thank you for your work. I found a few spelling mistakes - I fixed this
>>> and added some information about generating a partial index plan. I
>>> attached it.
>> Thanks Jian and Alena,
>> It is a good start for the documentation. But I think the runtime-config
>> section needs only a condensed description of a feature underlying the
>> GUC. The explanations in this section look a bit awkward.
>> Having looked through the documentation for a better place for a
>> detailed explanation, I found array.sgml as a candidate. Also, we have
>> the parser's short overview section. I'm unsure about the best place but
>> it is better when the server config section.
> doc/src/sgml/array.sgml corresponds to
> https://www.postgresql.org/docs/current/arrays.html.
>   this GUC is related to parser|optimzier.
> adding a GUC to array.sgml seems strange. (I think).

I suggest describing our feature in array.sgml and mentioning a GUC there.

We can describe a GUC in config.sgml.

>> 2. We should describe the second part of the feature, where the
>> optimiser can split an array to fit the optimal BitmapOr scan path.
> we can add a sentence explaining that:
> it may not do the expression transformation when the original
> expression can be utilized by index mechanism.
> I am not sure how to rephrase it.

Maybe like that:

It also considers the way to generate a path using BitmapScan indexes, 
converting the transformed expression into expressions separated by "OR" 
operations, and if it turns out to be the best and finally selects the 
best one.

-- 
Regards,
Alena Rybakina
Postgres Professional: http://www.postgrespro.com
The Russian Postgres Company