[YSQL] Partition with out-of-order columns constructs incorrect UPDATE payload

[karthik-ramanathan-3006]

Jira Link: DB-14778

Description

Behavior observed on master (4a9292c / YugabyteDB on PG 15).

Consider the following test adapted from insert_conflict.sql

create table parted_conflict_test (a int unique, b char) partition by list (a);
create table parted_conflict_test_2 (b char, a int unique);
alter table parted_conflict_test attach partition parted_conflict_test_2 for values in (3);

insert into parted_conflict_test values (3, 'a') on conflict (a) do update set b = excluded.b;

-- The following query constructs incorrect UPDATE payload
insert into parted_conflict_test values (3, 'b') on conflict (a) do update set b = excluded.b;

Running the following SELECT query should give:

postgres=# select * from parted_conflict_test order by a;
 a | b
---+---
 3 | b
(1 row)

while it produces:

yugabyte=# select * from parted_conflict_test order by a;
 a | b
---+---
 3 | a
(1 row)

Relevant DocDB logs:

2025-01-08 03:31:07.904 IST [43147] DEBUG:  No cols in category: Columns that are inspected and modified
2025-01-08 03:31:07.904 IST [43147] DEBUG:  No cols in category: Columns that are inspected and unmodified
2025-01-08 03:31:07.904 IST [43147] DEBUG:  Relation: 21319	Columns that are marked for update: 2 (10)
I0107 14:01:07.904209 4055927808 pg_session.cc:289] Session id 2: Buffering operation: { WRITE active: 1 read_time: { read: <invalid> local_limit: <invalid> global_limit: <invalid> in_txn_limit: <invalid> serial_no: 0 } request: client: YQL_CLIENT_PGSQL stmt_id: 4719304992 stmt_type: PGSQL_UPDATE table_id: "000034cb000030008000000000005354" schema_version: 1 hash_code: 14030 ybctid_column_value { value { binary_value: "4736CE539446430562664B6D8908C19A0B53AE9500002121" } } column_new_values { column_id: 2 expr { value { int32_value: 3 } } } column_refs { ids: 2 } col_refs { column_id: 2 attno: 2 } partition_key: "6�" ysql_db_catalog_version: 119 ysql_db_oid: 13515 }

Column 2(10) corresponds to column b in the parent while 1(9) references the same column in the child partition.
However, notice that the update to the table uses column ID 2.

#14985 references a similar issue but was reported on YugabyteDB on PG 11.

Issue Type

kind/bug

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