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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: 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, Ranier Vilela <ranier.vf@gmail.com>, Tomas Vondra <tomas.vondra@enterprisedb.com>, Peter Eisentraut <peter@eisentraut.org>, jian he <jian.universality@gmail.com>
Date: 2024-02-12T10:51:45Z
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 12.02.2024 12:01, Andrei Lepikhov wrote:
> On 12/2/2024 15:55, Alena Rybakina wrote:
>> Hi!
>>
>> I can't unnderstand this part of code:
>>
>> /* Time to generate index paths */
>>
>> MemSet(&clauseset, 0, sizeof(clauseset));
>> match_clauses_to_index(root, list_make1(rinfo1), index, &clauseset);
>>
>> As I understand it, match_clauses_to_index is necessary if you have a 
>> RestrictInfo (rinfo1) variable, so maybe we should run it after the 
>> make_restrictonfo procedure, otherwise calling it, I think, is useless.
> I think you must explain your note in more detail. Before this call, 
> we already called make_restrictinfo() and built rinfo1, haven't we?
>
I got it, I think, I was confused by the “else“ block when we can 
process the index, otherwise we move on to the next element.

I think maybe “else“ block of creating restrictinfo with the indexpaths 
list creation should be moved to a separate function or just remove "else"?


I think we need to check that rinfo->clause is not empty, because if it 
is we can miss calling build_paths_for_OR function. We should add it there:

restriction_is_saop_clause(RestrictInfo *restrictinfo)
{
     if (IsA(restrictinfo->clause, ScalarArrayOpExpr))
...


By the way, I think we need to add a check that the clauseset is not 
empty (if (!clauseset.nonempty)) otherwise we could get an error. The 
same check I noticed in build_paths_for_OR function.

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