From 1b2ac961c4c48841a6115a2aeaac27180623ea0f Mon Sep 17 00:00:00 2001
From: Man Zeng <zengman@halodbtech.com>
Date: Thu, 2 Jul 2026 11:16:40 +0800
Subject: [PATCH] Properties orphaned by dropping a label

AlterPropGraph() cleans up pg_propgraph_property entries that are
orphaned by dropping an element or by dropping properties associated
with an element. But it doesn't clean up pg_propgraph_property entries
that are orphaned by dropping labels associated with an element. Fix this
missing case.

Author: Ashutosh Bapat <ashutosh.bapat.oss@gmail.com>
Author: zengman <zengman@halodbtech.com>
Reported-by: zengman <zengman@halodbtech.com>
---
 src/backend/commands/propgraphcmds.c          |  3 ++-
 .../expected/create_property_graph.out        | 23 +++++++++----------
 .../regress/sql/create_property_graph.sql     |  5 ++++
 3 files changed, 18 insertions(+), 13 deletions(-)

diff --git a/src/backend/commands/propgraphcmds.c b/src/backend/commands/propgraphcmds.c
index cc516e27020..8d8b7318cf5 100644
--- a/src/backend/commands/propgraphcmds.c
+++ b/src/backend/commands/propgraphcmds.c
@@ -1638,7 +1638,8 @@ AlterPropGraph(ParseState *pstate, const AlterPropGraphStmt *stmt)
 	}
 
 	/* Remove any orphaned pg_propgraph_property entries */
-	if (stmt->drop_properties || stmt->drop_vertex_tables || stmt->drop_edge_tables)
+	if (stmt->drop_properties || stmt->drop_vertex_tables ||
+		stmt->drop_edge_tables || stmt->drop_label)
 	{
 		foreach_oid(propoid, get_graph_property_ids(pgrelid))
 		{
diff --git a/src/test/regress/expected/create_property_graph.out b/src/test/regress/expected/create_property_graph.out
index 2f06c7ce5a8..9a6018d717a 100644
--- a/src/test/regress/expected/create_property_graph.out
+++ b/src/test/regress/expected/create_property_graph.out
@@ -82,6 +82,11 @@ CREATE PROPERTY GRAPH g4
     );
 ALTER PROPERTY GRAPH g4 ALTER VERTEX TABLE t2 ALTER LABEL t2 ADD PROPERTIES (k * 2 AS kk);
 ALTER PROPERTY GRAPH g4 ALTER VERTEX TABLE t2 ALTER LABEL t2 DROP PROPERTIES (k);
+-- Dropping a label should drop only orphaned properties. zz is orphaned because
+-- it is only associated with the dropped label t3l2, while x is not orphaned
+-- because it remains associated with t3l1. We will verify this in the
+-- information schema queries outputs below.
+ALTER PROPERTY GRAPH g4 ALTER VERTEX TABLE t3 DROP LABEL t3l2;
 CREATE TABLE t11 (a int PRIMARY KEY);
 CREATE TABLE t12 (b int PRIMARY KEY);
 CREATE TABLE t13 (
@@ -439,7 +444,6 @@ SELECT * FROM information_schema.pg_element_table_labels ORDER BY property_graph
  regression             | create_property_graph_tests | g4                  | t1                  | t1
  regression             | create_property_graph_tests | g4                  | t2                  | t2
  regression             | create_property_graph_tests | g4                  | t3                  | t3l1
- regression             | create_property_graph_tests | g4                  | t3                  | t3l2
  regression             | create_property_graph_tests | g5                  | t11                 | t11
  regression             | create_property_graph_tests | g5                  | t12                 | t12
  regression             | create_property_graph_tests | g5                  | t13                 | t13
@@ -451,7 +455,7 @@ SELECT * FROM information_schema.pg_element_table_labels ORDER BY property_graph
  regression             | create_property_graph_tests | gt                  | e                   | e
  regression             | create_property_graph_tests | gt                  | v1                  | v1
  regression             | create_property_graph_tests | gt                  | v2                  | v2
-(26 rows)
+(25 rows)
 
 SELECT * FROM information_schema.pg_element_table_properties ORDER BY property_graph_name, element_table_alias, property_name;
  property_graph_catalog |    property_graph_schema    | property_graph_name | element_table_alias | property_name |         property_expression          
@@ -485,7 +489,6 @@ SELECT * FROM information_schema.pg_element_table_properties ORDER BY property_g
  regression             | create_property_graph_tests | g4                  | t2                  | kk            | (k * 2)
  regression             | create_property_graph_tests | g4                  | t3                  | x             | x
  regression             | create_property_graph_tests | g4                  | t3                  | yy            | y
- regression             | create_property_graph_tests | g4                  | t3                  | zz            | z
  regression             | create_property_graph_tests | g5                  | t11                 | a             | a
  regression             | create_property_graph_tests | g5                  | t12                 | b             | b
  regression             | create_property_graph_tests | g5                  | t13                 | c             | c
@@ -510,7 +513,7 @@ SELECT * FROM information_schema.pg_element_table_properties ORDER BY property_g
  regression             | create_property_graph_tests | gt                  | v1                  | b             | b
  regression             | create_property_graph_tests | gt                  | v2                  | m             | m
  regression             | create_property_graph_tests | gt                  | v2                  | n             | n
-(54 rows)
+(53 rows)
 
 SELECT * FROM information_schema.pg_label_properties ORDER BY property_graph_name, label_name, property_name;
  property_graph_catalog |    property_graph_schema    | property_graph_name | label_name | property_name 
@@ -550,8 +553,6 @@ SELECT * FROM information_schema.pg_label_properties ORDER BY property_graph_nam
  regression             | create_property_graph_tests | g4                  | t2         | kk
  regression             | create_property_graph_tests | g4                  | t3l1       | x
  regression             | create_property_graph_tests | g4                  | t3l1       | yy
- regression             | create_property_graph_tests | g4                  | t3l2       | x
- regression             | create_property_graph_tests | g4                  | t3l2       | zz
  regression             | create_property_graph_tests | g5                  | t11        | a
  regression             | create_property_graph_tests | g5                  | t12        | b
  regression             | create_property_graph_tests | g5                  | t13        | c
@@ -576,7 +577,7 @@ SELECT * FROM information_schema.pg_label_properties ORDER BY property_graph_nam
  regression             | create_property_graph_tests | gt                  | v1         | b
  regression             | create_property_graph_tests | gt                  | v2         | m
  regression             | create_property_graph_tests | gt                  | v2         | n
-(61 rows)
+(59 rows)
 
 SELECT * FROM information_schema.pg_labels ORDER BY property_graph_name, label_name;
  property_graph_catalog |    property_graph_schema    | property_graph_name | label_name 
@@ -595,7 +596,6 @@ SELECT * FROM information_schema.pg_labels ORDER BY property_graph_name, label_n
  regression             | create_property_graph_tests | g4                  | t1
  regression             | create_property_graph_tests | g4                  | t2
  regression             | create_property_graph_tests | g4                  | t3l1
- regression             | create_property_graph_tests | g4                  | t3l2
  regression             | create_property_graph_tests | g5                  | t11
  regression             | create_property_graph_tests | g5                  | t12
  regression             | create_property_graph_tests | g5                  | t13
@@ -607,7 +607,7 @@ SELECT * FROM information_schema.pg_labels ORDER BY property_graph_name, label_n
  regression             | create_property_graph_tests | gt                  | e
  regression             | create_property_graph_tests | gt                  | v1
  regression             | create_property_graph_tests | gt                  | v2
-(26 rows)
+(25 rows)
 
 SELECT * FROM information_schema.pg_property_data_types ORDER BY property_graph_name, property_name;
  property_graph_catalog |    property_graph_schema    | property_graph_name | property_name |     data_type     | character_maximum_length | character_octet_length | character_set_catalog | character_set_schema | character_set_name | collation_catalog | collation_schema | collation_name | numeric_precision | numeric_precision_radix | numeric_scale | datetime_precision | interval_type | interval_precision | user_defined_type_catalog | user_defined_type_schema | user_defined_type_name | scope_catalog | scope_schema | scope_name | maximum_cardinality | dtd_identifier 
@@ -633,7 +633,6 @@ SELECT * FROM information_schema.pg_property_data_types ORDER BY property_graph_
  regression             | create_property_graph_tests | g4                  | t             | text              |                          |                        |                       |                      |                    | regression        |                  |                |                   |                         |               |                    |               |                    | regression                | pg_catalog               | text                   |               |              |            |                     | t
  regression             | create_property_graph_tests | g4                  | x             | integer           |                          |                        |                       |                      |                    | regression        |                  |                |                   |                         |               |                    |               |                    | regression                | pg_catalog               | int4                   |               |              |            |                     | x
  regression             | create_property_graph_tests | g4                  | yy            | text              |                          |                        |                       |                      |                    | regression        |                  |                |                   |                         |               |                    |               |                    | regression                | pg_catalog               | text                   |               |              |            |                     | yy
- regression             | create_property_graph_tests | g4                  | zz            | text              |                          |                        |                       |                      |                    | regression        |                  |                |                   |                         |               |                    |               |                    | regression                | pg_catalog               | text                   |               |              |            |                     | zz
  regression             | create_property_graph_tests | g5                  | a             | integer           |                          |                        |                       |                      |                    | regression        |                  |                |                   |                         |               |                    |               |                    | regression                | pg_catalog               | int4                   |               |              |            |                     | a
  regression             | create_property_graph_tests | g5                  | b             | integer           |                          |                        |                       |                      |                    | regression        |                  |                |                   |                         |               |                    |               |                    | regression                | pg_catalog               | int4                   |               |              |            |                     | b
  regression             | create_property_graph_tests | g5                  | c             | integer           |                          |                        |                       |                      |                    | regression        |                  |                |                   |                         |               |                    |               |                    | regression                | pg_catalog               | int4                   |               |              |            |                     | c
@@ -651,7 +650,7 @@ SELECT * FROM information_schema.pg_property_data_types ORDER BY property_graph_
  regression             | create_property_graph_tests | gt                  | k2            | text              |                          |                        |                       |                      |                    | regression        |                  |                |                   |                         |               |                    |               |                    | regression                | pg_catalog               | text                   |               |              |            |                     | k2
  regression             | create_property_graph_tests | gt                  | m             | text              |                          |                        |                       |                      |                    | regression        |                  |                |                   |                         |               |                    |               |                    | regression                | pg_catalog               | text                   |               |              |            |                     | m
  regression             | create_property_graph_tests | gt                  | n             | text              |                          |                        |                       |                      |                    | regression        |                  |                |                   |                         |               |                    |               |                    | regression                | pg_catalog               | text                   |               |              |            |                     | n
-(39 rows)
+(38 rows)
 
 SELECT * FROM information_schema.pg_property_graph_privileges WHERE grantee LIKE 'regress%' ORDER BY property_graph_name, grantor, grantee, privilege_type;
        grantor       |       grantee       | property_graph_catalog |    property_graph_schema    | property_graph_name | privilege_type | is_grantable 
@@ -801,7 +800,7 @@ CREATE PROPERTY GRAPH create_property_graph_tests.g4
     VERTEX TABLES (
         t1 KEY (a) NO PROPERTIES,
         t2 KEY (i) PROPERTIES ((i + j) AS i_j, (k * 2) AS kk),
-        t3 KEY (x) LABEL t3l1 PROPERTIES (x, y AS yy) LABEL t3l2 PROPERTIES (x, z AS zz)
+        t3 KEY (x) LABEL t3l1 PROPERTIES (x, y AS yy)
     )
     EDGE TABLES (
         e1 KEY (a, i) SOURCE KEY (a) REFERENCES t1 (a) DESTINATION KEY (i) REFERENCES t2 (i) PROPERTIES (a, i, t),
diff --git a/src/test/regress/sql/create_property_graph.sql b/src/test/regress/sql/create_property_graph.sql
index 85088ae632c..c1ceaba7384 100644
--- a/src/test/regress/sql/create_property_graph.sql
+++ b/src/test/regress/sql/create_property_graph.sql
@@ -75,6 +75,11 @@ CREATE PROPERTY GRAPH g4
 
 ALTER PROPERTY GRAPH g4 ALTER VERTEX TABLE t2 ALTER LABEL t2 ADD PROPERTIES (k * 2 AS kk);
 ALTER PROPERTY GRAPH g4 ALTER VERTEX TABLE t2 ALTER LABEL t2 DROP PROPERTIES (k);
+-- Dropping a label should drop only orphaned properties. zz is orphaned because
+-- it is only associated with the dropped label t3l2, while x is not orphaned
+-- because it remains associated with t3l1. We will verify this in the
+-- information schema queries outputs below.
+ALTER PROPERTY GRAPH g4 ALTER VERTEX TABLE t3 DROP LABEL t3l2;
 
 CREATE TABLE t11 (a int PRIMARY KEY);
 CREATE TABLE t12 (b int PRIMARY KEY);
-- 
2.45.2

