[Bug] GPORCA crashes the coordinator with dependencies extended statistics

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Évaluation

Difficulté
4/5
Temps estimé
3-5 jours
Accessibilité débutants
30/100
Type d'issue
Bug
Clarté
Plutôt claire
Activité
Active
Stack technique
c, cpp, postgresql, sql
Domaine
databases

Piste de recherche

Start by running the reproduction SQL with optimizer = on to confirm the SIGSEGV and capture a backtrace. The payload points to CExtendedStatsProcessor.cpp, where colid_to_attno_mapping->Find(&colid) is dereferenced without a null check around lines 279 and 355/365, while the check near line 431 does test for null. Done means the query returns one row (NULL | NULL | f) with optimizer on and the crash no longer occurs, with a regression test added.

Rédigé par le modèle d'indexation à partir du texte de l'issue.

Description

type: Bug
Apache Cloudberry version

No response

What happened

Reproduce:

CREATE TABLE t1 (c0 name, c1 numeric, c2 boolean) DISTRIBUTED BY (c2);
INSERT INTO t1 VALUES ('a', 0.9, false), (NULL, NULL, false), ('', 0.1, false), ('1', 0.7, true), ('b', 0.5, NULL), ('', NULL, NULL), ('c', NULL, NULL);
CREATE STATISTICS s1 ON c0, c2 FROM t1;
CREATE STATISTICS s2 ON c1, c2 FROM t1;
ANALYZE t1;

SET optimizer = on;

SELECT * FROM (SELECT c0 AS a, c1 AS b, c2 AS c FROM t1 WHERE c2 IS FALSE) AS r WHERE r.a IS NULL AND r.b IS NULL AND r.c = FALSE;
  -- server closed the connection unexpectedly

Expected: one row, NULL | NULL | f. That's what you get with optimizer = off, or with optimizer = on after dropping s1 and s2.

  Actual: the coordinator backend crashes, and all other sessions are reset while the cluster recovers:
  PANIC: Unexpected internal error: Master process received signal SIGSEGV
  server process (PID ...) was terminated by signal 11: Segmentation fault

  Stack (top frames):
  gpnaucrates::CFilterStatsProcessor::MakeHistHashMapConjFilter
  gpnaucrates::CFilterStatsProcessor::MakeStatsFilter
  gpnaucrates::CFilterStatsProcessor::MakeStatsFilterForScalarExpr
  gpopt::CLogicalSelect::PstatsDerive
  gpopt::CExpressionHandle::DeriveRootStats
  ...
  gpopt::CEngine::FinalizeExploration

Possible cause: MakeHistHashMapConjFilter calls CExtendedStatsProcessor::ApplyCorrelatedStatsToScaleFactorFilterCalculation. In that function, the result of colid_to_attno_mapping->Find(&colid) is dereferenced
without a null check (CExtendedStatsProcessor.cpp, around lines 279 and 355/365), while another call site (around line 431) does check for null. The filter here sits above a subquery and spans columns from two
different dependency statistics objects, which may produce a column ID with no mapping. I haven't confirmed this in a debugger.

What you think should happen instead

No response

How to reproduce
CREATE TABLE t1 (c0 name, c1 numeric, c2 boolean) DISTRIBUTED BY (c2);
INSERT INTO t1 VALUES ('a', 0.9, false), (NULL, NULL, false), ('', 0.1, false), ('1', 0.7, true), ('b', 0.5, NULL), ('', NULL, NULL), ('c', NULL, NULL);
CREATE STATISTICS s1 ON c0, c2 FROM t1;
CREATE STATISTICS s2 ON c1, c2 FROM t1;
ANALYZE t1;

SET optimizer = on;

SELECT * FROM (SELECT c0 AS a, c1 AS b, c2 AS c FROM t1 WHERE c2 IS FALSE) AS r WHERE r.a IS NULL AND r.b IS NULL AND r.c = FALSE;
  -- server closed the connection unexpectedly
Operating System

any

Anything else

No response

Are you willing to submit PR?
  • Yes, I am willing to submit a PR!
Code of Conduct
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C
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