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* BUG #19470: PostgreSQL backend aborts (assert failure) when a prepared statement returns a composite type cast t
@ 2026-04-29 11:27 PG Bug reporting form <[email protected]>
0 siblings, 1 reply; 2+ messages in thread
From: PG Bug reporting form @ 2026-04-29 11:27 UTC (permalink / raw)
To: [email protected]; +Cc: [email protected]
The following bug has been logged on the website:
Bug reference: 19470
Logged by: HaoGang Mao
Email address: [email protected]
PostgreSQL version: 18.3
Operating system: Linux
Description:
Reproduction steps (minimal):
BEGIN;
CREATE TYPE foo AS (a int, b text);
PREPARE p AS SELECT CAST(ROW(1, 'hello') AS foo)::text;
EXECUTE p;
ALTER TYPE foo ALTER ATTRIBUTE a TYPE VARCHAR(100);
EXECUTE p;
COMMIT;
Expected: Error message (type modified while a prepared plan / expression is
active)
Actual: Server connection dropped; backend aborts with SIGABRT due to
assertion failure
Server log (trimmed):
TRAP: failed Assert("false"), File: "heaptuple.c", Line: 1417, PID: <pid>
... heap_deform_tuple()
^ permalink raw reply [nested|flat] 2+ messages in thread
* Re: BUG #19470: PostgreSQL backend aborts (assert failure) when a prepared statement returns a composite type cast t
@ 2026-05-05 02:36 Euler Taveira <[email protected]>
parent: PG Bug reporting form <[email protected]>
0 siblings, 0 replies; 2+ messages in thread
From: Euler Taveira @ 2026-05-05 02:36 UTC (permalink / raw)
To: [email protected]; [email protected]
On Wed, Apr 29, 2026, at 8:27 AM, PG Bug reporting form wrote:
>
> Reproduction steps (minimal):
> BEGIN;
> CREATE TYPE foo AS (a int, b text);
> PREPARE p AS SELECT CAST(ROW(1, 'hello') AS foo)::text;
> EXECUTE p;
> ALTER TYPE foo ALTER ATTRIBUTE a TYPE VARCHAR(100);
> EXECUTE p;
> COMMIT;
>
Thanks for your report! The attached patch fixes this case. I included a
similar test case but I'm fine if the test is not included with this fix. I
decided to create a separate function instead of adding the new conditions to
record_plan_type_dependency() because it keeps the fix simple and isolated.
The crash is reproduced back to v11 which means this fix should be backpatched
to all supported versions.
--
Euler Taveira
EDB https://www.enterprisedb.com/
Attachments:
[text/x-patch] v1-0001-Fix-a-crash-with-cached-plans-after-changing-comp.patch (5.4K, 2-v1-0001-Fix-a-crash-with-cached-plans-after-changing-comp.patch)
download | inline diff:
From 96c408c5029ea274a5a9599ffd9a97ef498e994e Mon Sep 17 00:00:00 2001
From: Euler Taveira <[email protected]>
Date: Mon, 4 May 2026 13:13:04 -0300
Subject: [PATCH v1] Fix a crash with cached plans after changing composite
types
If an existing prepared statement contains a composite type and a
subsequent ALTER TYPE command changes one of the attribute types, the
plan cache was never invalidated, resulting in a crash.
Add the composite type relation of any named composite type that appears
in Const and RowExpr nodes. The ALTER TYPE ... ALTER ATTRIBUTE command
already has the mechanism to send a relcache invalidation. It requires
that the composite type relation is added to relationOids list so the
PlanCacheRelCallback can find and invalidate the affected plans.
Bug: #19470
Reported-by: HaoGang Mao <[email protected]>
Author: Euler Taveira <[email protected]>
Discussion: https://postgr.es/m/[email protected]
---
src/backend/optimizer/plan/setrefs.c | 39 ++++++++++++++++++++++++-
src/test/regress/expected/plancache.out | 25 ++++++++++++++++
src/test/regress/sql/plancache.sql | 18 ++++++++++++
3 files changed, 81 insertions(+), 1 deletion(-)
diff --git a/src/backend/optimizer/plan/setrefs.c b/src/backend/optimizer/plan/setrefs.c
index ff0e875f2a2..fb73de0bd27 100644
--- a/src/backend/optimizer/plan/setrefs.c
+++ b/src/backend/optimizer/plan/setrefs.c
@@ -29,6 +29,7 @@
#include "rewrite/rewriteManip.h"
#include "tcop/utility.h"
#include "utils/syscache.h"
+#include "utils/typcache.h"
typedef enum
@@ -210,7 +211,8 @@ static List *set_returning_clause_references(PlannerInfo *root,
static List *set_windowagg_runcondition_references(PlannerInfo *root,
List *runcondition,
Plan *plan);
-
+static void record_plan_composite_type_dependency(PlannerInfo *root,
+ Oid typid);
static void record_elided_node(PlannerGlobal *glob, int plan_node_id,
NodeTag elided_type, Bitmapset *relids);
@@ -2157,6 +2159,13 @@ fix_expr_common(PlannerInfo *root, Node *node)
root->glob->relationOids =
lappend_oid(root->glob->relationOids,
DatumGetObjectId(con->constvalue));
+
+ record_plan_composite_type_dependency(root, con->consttype);
+ }
+ else if (IsA(node, RowExpr))
+ {
+ record_plan_composite_type_dependency(root,
+ ((RowExpr *) node)->row_typeid);
}
else if (IsA(node, GroupingFunc))
{
@@ -3692,6 +3701,34 @@ record_plan_type_dependency(PlannerInfo *root, Oid typid)
}
}
+/*
+ * record_plan_composite_type_dependency
+ * Mark the current plan as depending on a particular composite type.
+ *
+ * Add composite type relation to the list of the relations the plan depends
+ * on. This ensures that when ALTER TYPE ... ALTER ATTRIBUTE is executed, any
+ * plans that use this composite type will be invalidated.
+ */
+static void
+record_plan_composite_type_dependency(PlannerInfo *root, Oid typid)
+{
+ /*
+ * As in record_plan_function_dependency, ignore the possibility that
+ * someone would change a built-in composite type. Anonymous record types
+ * are not considered.
+ */
+ if (typid >= (Oid) FirstUnpinnedObjectId)
+ {
+ TypeCacheEntry *typentry;
+
+ typentry = lookup_type_cache(typid, 0);
+ if (typentry->typtype == TYPTYPE_COMPOSITE &&
+ OidIsValid(typentry->typrelid))
+ root->glob->relationOids =
+ lappend_oid(root->glob->relationOids, typentry->typrelid);
+ }
+}
+
/*
* extract_query_dependencies
* Given a rewritten, but not yet planned, query or queries
diff --git a/src/test/regress/expected/plancache.out b/src/test/regress/expected/plancache.out
index d58534ca1cd..766c430c862 100644
--- a/src/test/regress/expected/plancache.out
+++ b/src/test/regress/expected/plancache.out
@@ -402,3 +402,28 @@ select name, generic_plans, custom_plans from pg_prepared_statements
(1 row)
drop table test_mode;
+-- bug #19470: ALTER TYPE ... ALTER ATTRIBUTE should invalidate plans.
+-- Test compatible and incompatible attribute type changes.
+CREATE TYPE bug_19470 AS (a int, b text);
+PREPARE stmt_19470 AS SELECT CAST(ROW(1, 'hello') AS bug_19470)::text;
+EXECUTE stmt_19470;
+ row
+-----------
+ (1,hello)
+(1 row)
+
+-- should be ok
+ALTER TYPE bug_19470 ALTER ATTRIBUTE a TYPE varchar(100);
+EXECUTE stmt_19470;
+ row
+-----------
+ (1,hello)
+(1 row)
+
+-- should fail
+ALTER TYPE bug_19470 ALTER ATTRIBUTE a TYPE timestamp without time zone;
+EXECUTE stmt_19470;
+ERROR: cannot cast type record to bug_19470
+DETAIL: Cannot cast type integer to timestamp without time zone in column 1.
+DEALLOCATE stmt_19470;
+DROP TYPE bug_19470;
diff --git a/src/test/regress/sql/plancache.sql b/src/test/regress/sql/plancache.sql
index aed388d03a1..842a2137a37 100644
--- a/src/test/regress/sql/plancache.sql
+++ b/src/test/regress/sql/plancache.sql
@@ -228,3 +228,21 @@ select name, generic_plans, custom_plans from pg_prepared_statements
where name = 'test_mode_pp';
drop table test_mode;
+
+-- bug #19470: ALTER TYPE ... ALTER ATTRIBUTE should invalidate plans.
+-- Test compatible and incompatible attribute type changes.
+CREATE TYPE bug_19470 AS (a int, b text);
+
+PREPARE stmt_19470 AS SELECT CAST(ROW(1, 'hello') AS bug_19470)::text;
+EXECUTE stmt_19470;
+
+-- should be ok
+ALTER TYPE bug_19470 ALTER ATTRIBUTE a TYPE varchar(100);
+EXECUTE stmt_19470;
+
+-- should fail
+ALTER TYPE bug_19470 ALTER ATTRIBUTE a TYPE timestamp without time zone;
+EXECUTE stmt_19470;
+
+DEALLOCATE stmt_19470;
+DROP TYPE bug_19470;
--
2.39.5
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2026-04-29 11:27 BUG #19470: PostgreSQL backend aborts (assert failure) when a prepared statement returns a composite type cast t PG Bug reporting form <[email protected]>
2026-05-05 02:36 ` Euler Taveira <[email protected]>
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