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pgsql: Fix estimate_array_length error with set-operation array coercio
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* pgsql: Fix estimate_array_length error with set-operation array coercio
@ 2026-04-11 07:42 Richard Guo <rguo@postgresql.org>
  0 siblings, 0 replies; 3+ messages in thread

From: Richard Guo @ 2026-04-11 07:42 UTC (permalink / raw)
  To: pgsql-committers@lists.postgresql.org

Fix estimate_array_length error with set-operation array coercions

When a nested set operation's output type doesn't match the parent's
expected type, recurse_set_operations builds a projection target list
using generate_setop_tlist with varno 0.  If the required type
coercion involves an ArrayCoerceExpr, estimate_array_length could be
called on such a Var, and would pass it to examine_variable, which
errors in find_base_rel because varno 0 has no valid relation entry.

Fix by skipping the statistics lookup for Vars with varno 0.

Bug introduced by commit 9391f7152.  Back-patch to v17, where
estimate_array_length was taught to use statistics.

Reported-by: Justin Pryzby <pryzby@telsasoft.com>
Author: Tender Wang <tndrwang@gmail.com>
Reviewed-by: Richard Guo <guofenglinux@gmail.com>
Discussion: https://postgr.es/m/adjW8rfPDkplC7lF@pryzbyj2023
Backpatch-through: 17

Branch
------
master

Details
-------
https://git.postgresql.org/pg/commitdiff/77d0e82e58854cfa5e2c4f365a97f16c0d91c394

Modified Files
--------------
src/backend/utils/adt/selfuncs.c    | 12 ++++++++++++
src/test/regress/expected/union.out | 17 +++++++++++++++++
src/test/regress/sql/union.sql      |  4 ++++
3 files changed, 33 insertions(+)



^ permalink  raw  reply  [nested|flat] 3+ messages in thread

* pgsql: Fix estimate_array_length error with set-operation array coercio
@ 2026-04-11 07:42 Richard Guo <rguo@postgresql.org>
  0 siblings, 0 replies; 3+ messages in thread

From: Richard Guo @ 2026-04-11 07:42 UTC (permalink / raw)
  To: pgsql-committers@lists.postgresql.org

Fix estimate_array_length error with set-operation array coercions

When a nested set operation's output type doesn't match the parent's
expected type, recurse_set_operations builds a projection target list
using generate_setop_tlist with varno 0.  If the required type
coercion involves an ArrayCoerceExpr, estimate_array_length could be
called on such a Var, and would pass it to examine_variable, which
errors in find_base_rel because varno 0 has no valid relation entry.

Fix by skipping the statistics lookup for Vars with varno 0.

Bug introduced by commit 9391f7152.  Back-patch to v17, where
estimate_array_length was taught to use statistics.

Reported-by: Justin Pryzby <pryzby@telsasoft.com>
Author: Tender Wang <tndrwang@gmail.com>
Reviewed-by: Richard Guo <guofenglinux@gmail.com>
Discussion: https://postgr.es/m/adjW8rfPDkplC7lF@pryzbyj2023
Backpatch-through: 17

Branch
------
REL_18_STABLE

Details
-------
https://git.postgresql.org/pg/commitdiff/13e20d1c9d99516d13f3ee0dc164168a74cde0df

Modified Files
--------------
src/backend/utils/adt/selfuncs.c    | 12 ++++++++++++
src/test/regress/expected/union.out | 17 +++++++++++++++++
src/test/regress/sql/union.sql      |  4 ++++
3 files changed, 33 insertions(+)



^ permalink  raw  reply  [nested|flat] 3+ messages in thread

* pgsql: Fix estimate_array_length error with set-operation array coercio
@ 2026-04-11 07:42 Richard Guo <rguo@postgresql.org>
  0 siblings, 0 replies; 3+ messages in thread

From: Richard Guo @ 2026-04-11 07:42 UTC (permalink / raw)
  To: pgsql-committers@lists.postgresql.org

Fix estimate_array_length error with set-operation array coercions

When a nested set operation's output type doesn't match the parent's
expected type, recurse_set_operations builds a projection target list
using generate_setop_tlist with varno 0.  If the required type
coercion involves an ArrayCoerceExpr, estimate_array_length could be
called on such a Var, and would pass it to examine_variable, which
errors in find_base_rel because varno 0 has no valid relation entry.

Fix by skipping the statistics lookup for Vars with varno 0.

Bug introduced by commit 9391f7152.  Back-patch to v17, where
estimate_array_length was taught to use statistics.

Reported-by: Justin Pryzby <pryzby@telsasoft.com>
Author: Tender Wang <tndrwang@gmail.com>
Reviewed-by: Richard Guo <guofenglinux@gmail.com>
Discussion: https://postgr.es/m/adjW8rfPDkplC7lF@pryzbyj2023
Backpatch-through: 17

Branch
------
REL_17_STABLE

Details
-------
https://git.postgresql.org/pg/commitdiff/93ed18720105ebacfd2a2bdeb55bf33feaf2ec80

Modified Files
--------------
src/backend/utils/adt/selfuncs.c    | 12 ++++++++++++
src/test/regress/expected/union.out | 17 +++++++++++++++++
src/test/regress/sql/union.sql      |  4 ++++
3 files changed, 33 insertions(+)



^ permalink  raw  reply  [nested|flat] 3+ messages in thread


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