Horton

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: Nikolay Shaplov <dhyan@nataraj.su>, pgsql-hackers@lists.postgresql.org
Cc: Alexander Korotkov <aekorotkov@gmail.com>, Andrei Lepikhov <a.lepikhov@postgrespro.ru>, jian he <jian.universality@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: 2024-07-11T16:17:42Z
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,

Attachments

Hi, again!

I have finished patch and processed almost your suggestions (from [0], 
[1], [2]). It remainsonlyto addtestswherethe conversionshouldwork,butI 
willaddthis inthe nextversion.

[0] 
https://www.postgresql.org/message-id/3381819.e9J7NaK4W3%40thinkpad-pgpro

[1] 
https://www.postgresql.org/message-id/9736220.CDJkKcVGEf%40thinkpad-pgpro

[2] 
https://www.postgresql.org/message-id/2193851.QkHrqEjB74%40thinkpad-pgpro

On 09.07.2024 04:57, Alena Rybakina wrote:
>
> Hi! Thank you for your review! Sorryforthe delayin responding.
>
> Irewrotethe patchasyourequested,butnowI'm facedwiththe problemof 
> processingthe elementsof the or_entries list.For somereason, 
> thepointerto thelistis cleared and I couldn't find the place where it 
> happened.MaybeI'mmissingsomethingsimpleinviewof the heavyworkloadright 
> now,butmaybeyou'll seea problem?Ihave displayedpart of stackbelow.
>
> #5 0x00005b0f6d9f6a6a in ExceptionalCondition 
> (conditionName=0x5b0f6dbb74f7 "IsPointerList(list)", 
> fileName=0x5b0f6dbb7418 "list.c", lineNumber=341) at assert.c:66 #6 
> 0x00005b0f6d5dc3ba in lappend (list=0x5b0f6eec5ca0, 
> datum=0x5b0f6eec0d90) at list.c:341 #7 0x00005b0f6d69230c in 
> transform_or_to_any (root=0x5b0f6eeb13c8, orlist=0x5b0f6eec57c0) at 
> initsplan.c:2818 #8 0x00005b0f6d692958 in add_base_clause_to_rel 
> (root=0x5b0f6eeb13c8, relid=1, restrictinfo=0x5b0f6eec5990) at 
> initsplan.c:2982 #9 0x00005b0f6d692e5f in 
> distribute_restrictinfo_to_rels (root=0x5b0f6eeb13c8, 
> restrictinfo=0x5b0f6eec5990) at initsplan.c:3175 #10 
> 0x00005b0f6d691bf2 in distribute_qual_to_rels (root=0x5b0f6eeb13c8, 
> clause=0x5b0f6eec0fc0, jtitem=0x5b0f6eec4330, sjinfo=0x0, 
> security_level=0, qualscope=0x5b0f6eec4730, ojscope=0x0, 
> outerjoin_nonnullable=0x0, incompatible_relids=0x0, 
> allow_equivalence=true, has_clone=false, is_clone=false, 
> postponed_oj_qual_list=0x0) at initsplan.c:2576 #11 0x00005b0f6d69146f 
> in distribute_quals_to_rels (root=0x5b0f6eeb13c8, 
> clauses=0x5b0f6eec0bb0, jtitem=0x5b0f6eec4330, sjinfo=0x0, 
> security_level=0, qualscope=0x5b0f6eec4730, ojscope=0x0, 
> outerjoin_nonnullable=0x0, incompatible_relids=0x0, 
> allow_equivalence=true, has_clone=false, is_clone=false, 
> postponed_oj_qual_list=0x0) at initsplan.c:2144
>
> Thisis stillthe firstiterationof the fixesyouhave proposed,soI have 
> attachedthe patchindiffformat.I rewroteit,asyousuggestedinthe 
> firstletter[0].Icreateda separatefunctionthattriesto forman 
> OrClauseGroup node,butifit failsinthis, it returnsfalse,otherwiseit 
> processesthe generatedelementaccordingtowhat it found-eitheraddsit to 
> thelistasnew,oraddsa constantto anexistingone.
>
> Ialsodividedonegenerallistof 
> suitableforconversionandunsuitableintotwodifferentones:appropriate_entriesandor_entries.Nowweare 
> onlylookinginthe listof suitableelementstoformANYexpr.
>
> Thishelpsusto get ridofrepetitionsinthe codeyoumentioned. 
> Pleasewriteifthisis notthelogicthatyouhave seenbefore.
>
> [0] 
> https://www.postgresql.org/message-id/3381819.e9J7NaK4W3%40thinkpad-pgpro
>
The errorwascausedby the specificsof storingthe "OR"clausesinthe 
RestrictInfostructure.Scanning the orclauses list of the RestrictInfo 
variable, wecouldfacenotonlytheitem with RestrictInfo 
type,butalsotheBoolExpr type.

For example, when we have both or clauses and "AND" clauses together, 
like x = 1 and (y =1 or y=2 or y=3 and z = 1). The structure looks like:

RestrictInfo->orclauses = [RestrictInfo [x=1],
RestrictInfo->orclauses = [RestrictInfo[y=1],
                     RestrictInfo [y=2],
                     BoolExpr = [Restrictinfo [y=3], RestrictInfo [z=1]
                    ]
                                          ]

It'sworkingfinenow.

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