Re: postgres_fdw: Fix crash when estimating joins with functions

Fujii Masao писал(а) 2026-09-09 17:02:
> Hi,
>
> On master, I found that the following causes a segmentation fault:
>
> CREATE EXTENSION postgres_fdw;
> CREATE SERVER loopback FOREIGN DATA WRAPPER postgres_fdw;
> CREATE USER MAPPING FOR PUBLIC SERVER loopback;
> CREATE TABLE t (i int);
> CREATE FOREIGN TABLE ft (i int) SERVER loopback
> OPTIONS (table_name 't', use_remote_estimate 'true');
> EXPLAIN SELECT * FROM generate_series(1, 3) g JOIN ft ON ft.i = g;
>
> This crash seems to occur because init_func_stub_fpinfo() forgets to
> copy
> the user mapping to the function-side stub, leaving it NULL. The NULL
> mapping is then passed to GetConnection() when requesting a remote
> estimate, causing the segmentation fault.
>
> This seems to have been introduced by commit 0ee83dd4a99.
>
> The attached patch fixes this by also copying the user mapping from the
> foreign side.
>
> Regards,

Hi. Thanks. Looks good to me.

--
Best regards,
Alexander Pyhalov,
Postgres Professional