On Thu, Oct 30, 2025 at 9:02 AM PG Bug reporting form
<noreply@postgresql.org> wrote:
>
> The following bug has been logged on the website:
>
> Bug reference: 19099
> Logged by: Alexander Lakhin
> Email address: exclusion@gmail.com
> PostgreSQL version: 18.0
> Operating system: Ubuntu 24.04
> Description:
>
> The following script:
> CREATE EXTENSION file_fdw;
> CREATE SERVER file_server FOREIGN DATA WRAPPER file_fdw;
> CREATE TABLE pt (a int, b text) partition by list (a);
> CREATE FOREIGN TABLE p1 partition of pt for values in (1) SERVER file_server
> OPTIONS (format 'csv', filename '/tmp/1.csv');
> SET enable_partition_pruning = 'off';
> EXPLAIN DELETE FROM pt WHERE false;
>
> raises:
> ERROR: XX000: could not find junk ctid column
> LOCATION: ExecInitModifyTable, nodeModifyTable.c:4867
> (Discovered with SQLsmith.)
>
> Reproduced starting from 86dc9005.
>
> On 86dc9005~1 or with enable_partition_pruning = 'on', EXPLAIN outputs the
> query plan and "DELETE FROM pt WHERE false;" completes with no error.
>
we can add a postgresAddForeignUpdateTargets(postgres_fdw) equivalent
function for file_fdw even though we do not support UPDATE/DELETE in file_fdw.
After applying your patch, I got a different output if I enable verbose in EXPLAIN:
postgres=# EXPLAIN verbose DELETE FROM pt WHERE false;
QUERY PLAN
-------------------------------------------------------
Delete on
public.pt (cost=0.00..0.00 rows=0 width=0)
-> Result (cost=0.00..0.00 rows=0 width=0)
Output: ctid
Replaces: Scan on pt
One-Time Filter: false
(5 rows)
postgres=# set enable_partition_pruning = 'off';
SET
postgres=# EXPLAIN verbose DELETE FROM pt WHERE false;
QUERY PLAN
-------------------------------------------------------
Delete on
public.pt (cost=0.00..0.00 rows=0 width=0)
-> Result (cost=0.00..0.00 rows=0 width=0)
Output: NULL::oid, NULL::tid
Replaces: Scan on pt
One-Time Filter: false
(5 rows)
Output: ctid (enable_partition_pruning = on)
vs
Output: NULL::oid, NULL::tid(enable_partition_pruning = off)
I try add childrte->relkind != RELKIND_PARTITIONED_TABLE && childrte->relkind != RELKIND_FOREIGN_TABLE)
to avoid adding "tableoid" for foreign table in expand_single_inheritance_child().
It works, but the file_fdw regression test failed.
I added Tom and Amit to the cc list.
Any thoughts?
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