BUG #19390: Defects in the test case partition_merge

The following bug has been logged on the website:

Bug reference: 19390
Logged by: fairyfar
Email address: fairyfar(at)msn(dot)com
PostgreSQL version: Unsupported/Unknown
Operating system: Linux
Description:

# PostgreSQL version

git branch: master
git commit id: 851f6649cc18c4b482fa2b6afddb65b35d035370

# Problem

In my test environment, the next OID of PostgreSQL is greater than 2^31.
The partition_merge failure in regression testing:

```bash
[yz(at)bogon regress]$ ./pg_regress --schedule=parallel_schedule
...
# parallel group (18 tests): compression_lz4 numa hash_part explain
reloptions predicate partition_info compression memoize eager_aggregate
tuplesort partition_aggregate partition_merge partition_split
partition_prune indexing partition_join stats
not ok 215 + partition_merge 16421 ms
...

[yz(at)bogon regress]$ cat regression.diffs
diff -U3
/home/yz/postgresql/postgres_src/src/test/regress/expected/partition_merge.out
/home/yz/postgresql/postgres_src/src/test/regress/results/partition_merge.out
---
/home/yz/postgresql/postgres_src/src/test/regress/expected/partition_merge.out
2026-01-27 14:36:29.093904247 +0800
+++
/home/yz/postgresql/postgres_src/src/test/regress/results/partition_merge.out
2026-01-28 14:51:09.227253112 +0800
@@ -1068,26 +1068,27 @@
ALTER TABLE t ADD CHECK (g > 0);
ALTER TABLE t ADD CHECK (i > 0);
INSERT INTO t VALUES (5), (15);
+ERROR: new row for relation "tp_1" violates check constraint "t_g_check"
+DETAIL: Failing row contains (5, virtual).
ALTER TABLE t MERGE PARTITIONS (tp_1, tp_2) INTO tp_12;
INSERT INTO t VALUES (16);
+ERROR: new row for relation "tp_12" violates check constraint "t_g_check"
+DETAIL: Failing row contains (16, virtual).
-- ERROR: new row for relation "tp_12" violates check constraint
"t_i_check"
INSERT INTO t VALUES (0);
-ERROR: new row for relation "tp_12" violates check constraint "t_i_check"
+ERROR: new row for relation "tp_12" violates check constraint "t_g_check"
DETAIL: Failing row contains (0, virtual).
-- Should be 3 rows: (5), (15), (16):
SELECT i FROM t ORDER BY i;
- i
-----
- 5
- 15
- 16
-(3 rows)
+ i
+---
+(0 rows)

-- Should be 1 because for the same tableoid (15 + tableoid) = (5 +
tableoid) + 10:
SELECT count(*) FROM t WHERE i = 15 AND g IN (SELECT g + 10 FROM t WHERE i
= 5);
count
-------
- 1
+ 0
(1 row)

DROP TABLE t;
```

# Root Cause

OID is unsigned int. So, when OID is greater than 2^n, converting it to int
will result in a negative value.

# Solution

```bash
[yz(at)bogon postgres_src]$ git diff
diff --git a/src/test/regress/expected/partition_merge.out
b/src/test/regress/expected/partition_merge.out
index 925fe4f570a..75d1e42511e 100644
--- a/src/test/regress/expected/partition_merge.out
+++ b/src/test/regress/expected/partition_merge.out
@@ -1033,7 +1033,7 @@ DETAIL: Key (i)=(2) is not present in table "t".
DROP TABLE t_fk;
DROP TABLE t;
-- Test for recomputation of stored generated columns.
-CREATE TABLE t (i int, tab_id int generated always as (tableoid) stored)
PARTITION BY RANGE (i);
+CREATE TABLE t (i bigint, tab_id bigint generated always as (tableoid)
stored) PARTITION BY RANGE (i);
CREATE TABLE tp_0_1 PARTITION OF t FOR VALUES FROM (0) TO (1);
CREATE TABLE tp_1_2 PARTITION OF t FOR VALUES FROM (1) TO (2);
ALTER TABLE t ADD CONSTRAINT cc CHECK(tableoid <> 123456789);
@@ -1060,9 +1060,9 @@ SELECT count(*) FROM t WHERE i = 0 AND tab_id IN
(SELECT tab_id FROM t WHERE i =
DROP TABLE t;
-- Test for generated columns (different order of columns in partitioned
table
-- and partitions).
-CREATE TABLE t (i int, g int GENERATED ALWAYS AS (i + tableoid::int))
PARTITION BY RANGE (i);
-CREATE TABLE tp_1 (g int GENERATED ALWAYS AS (i + tableoid::int), i int);
-CREATE TABLE tp_2 (g int GENERATED ALWAYS AS (i + tableoid::int), i int);
+CREATE TABLE t (i bigint, g bigint GENERATED ALWAYS AS (i +
tableoid::bigint)) PARTITION BY RANGE (i);
+CREATE TABLE tp_1 (g bigint GENERATED ALWAYS AS (i + tableoid::bigint), i
bigint);
+CREATE TABLE tp_2 (g bigint GENERATED ALWAYS AS (i + tableoid::bigint), i
bigint);
ALTER TABLE t ATTACH PARTITION tp_1 FOR VALUES FROM (-1) TO (10);
ALTER TABLE t ATTACH PARTITION tp_2 FOR VALUES FROM (10) TO (20);
ALTER TABLE t ADD CHECK (g > 0);
diff --git a/src/test/regress/sql/partition_merge.sql
b/src/test/regress/sql/partition_merge.sql
index a211fee2ad1..721a313fbd4 100644
--- a/src/test/regress/sql/partition_merge.sql
+++ b/src/test/regress/sql/partition_merge.sql
@@ -739,7 +739,7 @@ DROP TABLE t;

-- Test for recomputation of stored generated columns.
-CREATE TABLE t (i int, tab_id int generated always as (tableoid) stored)
PARTITION BY RANGE (i);
+CREATE TABLE t (i bigint, tab_id bigint generated always as (tableoid)
stored) PARTITION BY RANGE (i);
CREATE TABLE tp_0_1 PARTITION OF t FOR VALUES FROM (0) TO (1);
CREATE TABLE tp_1_2 PARTITION OF t FOR VALUES FROM (1) TO (2);
ALTER TABLE t ADD CONSTRAINT cc CHECK(tableoid <> 123456789);
@@ -762,9 +762,9 @@ DROP TABLE t;

-- Test for generated columns (different order of columns in partitioned
table
-- and partitions).
-CREATE TABLE t (i int, g int GENERATED ALWAYS AS (i + tableoid::int))
PARTITION BY RANGE (i);
-CREATE TABLE tp_1 (g int GENERATED ALWAYS AS (i + tableoid::int), i int);
-CREATE TABLE tp_2 (g int GENERATED ALWAYS AS (i + tableoid::int), i int);
+CREATE TABLE t (i bigint, g bigint GENERATED ALWAYS AS (i +
tableoid::bigint)) PARTITION BY RANGE (i);
+CREATE TABLE tp_1 (g bigint GENERATED ALWAYS AS (i + tableoid::bigint), i
bigint);
+CREATE TABLE tp_2 (g bigint GENERATED ALWAYS AS (i + tableoid::bigint), i
bigint);
ALTER TABLE t ATTACH PARTITION tp_1 FOR VALUES FROM (-1) TO (10);
ALTER TABLE t ATTACH PARTITION tp_2 FOR VALUES FROM (10) TO (20);
ALTER TABLE t ADD CHECK (g > 0);
```