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

Robert Haas <robertmhaas@gmail.com>

From: Robert Haas <robertmhaas@gmail.com>

To: Tom Lane <tgl@sss.pgh.pa.us>

Cc: Peter Geoghegan <pg@bowt.ie>, Alexander Korotkov <aekorotkov@gmail.com>, Andrei Lepikhov <lepihov@gmail.com>, 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>

Date: 2024-10-07T16:43:36Z

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 →

Make group_similar_or_args() reorder clause list as little as possible
- 775a06d44c04 18.0 landed
Allow usage of match_orclause_to_indexcol() for joins
- 627d63419e22 18.0 landed
Skip not SOAP-supported indexes while transforming an OR clause into SAOP
- 5bba0546eecb 18.0 landed
Remove the wrong assertion from match_orclause_to_indexcol()
- d4d11940df94 18.0 landed
Teach bitmap path generation about transforming OR-clauses to SAOP's
- ae4569161a27 18.0 landed
Transform OR-clauses to SAOP's during index matching
- d4378c0005e6 18.0 landed
Fix the value of or_to_any_transform_limit in postgresql.conf.sample
- 2af75e117478 17.0 landed
Transform OR clauses to ANY expression
- 72bd38cc99a1 17.0 landed
MergeAttributes code deduplication
- 64444ce071f6 17.0 cited
SEARCH and CYCLE clauses
- 3696a600e229 14.0 cited
Improve estimation of OR clauses using extended statistics.
- 25a9e54d2db3 14.0 cited
Teach btree to handle ScalarArrayOpExpr quals natively.
- 9e8da0f75731 9.2.0 cited
Revise collation derivation method and expression-tree representation.
- b310b6e31ce5 9.1.0 cited
Instead of trying to force WHERE clauses into CNF or DNF normal form,
- 9888192fb773 8.0.0 cited

On Mon, Oct 7, 2024 at 12:02 PM Tom Lane <tgl@sss.pgh.pa.us> wrote:
> Peter Geoghegan <pg@bowt.ie> writes:
> > To be clear, I don't think that it's essential that we have equivalent
> > behavior in those cases where the patch applies its transformations. I
> > have no objections to committing the patch without any handling for
> > that.
>
> Oy.  I don't agree with that *at all*.  An "optimization" that changes
> query semantics is going to be widely seen as a bug.

I think everyone agrees on that. The issue is that I don't know how to
implement the optimization Peter wants without changing the query
semantics, and it seems like Alexander doesn't either. By committing
the patch without that optimization, we're *avoiding* changing the
query semantics.

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