Re: BUG #18763: pg_get_viewdef returns an old def with new relation name

On Thu, 2 Jan 2025 at 15:19, PG Bug reporting form
<noreply(at)postgresql(dot)org> wrote:
>
> The following bug has been logged on the website:
>
> Bug reference: 18763
> Logged by: lyz
> Email address: linyuzhe(dot)lyz(at)gmail(dot)com
> PostgreSQL version: 13.7
> Operating system: Linux
> Description:
>
> in first connection
>
> test5=# create table a1(c int);
> CREATE TABLE
> test5=# create table a2(c int);
> CREATE TABLE
> test5=# create view v as select * from a1;
> CREATE VIEW
>
> then rename relation names and replace view in one txn, but not commit.
>
> test5=# begin;
> BEGIN
> test5=*# alter table a1 rename to a3;
> ALTER TABLE
> test5=*# alter table a2 rename to a1;
> ALTER TABLE
> test5=*# create or replace view v as select * from a1;
> CREATE VIEW
>
> in second connection:
>
> test5=# select pg_get_viewdef('v');
>
> it will be stuck by AccessShareLock of 'v'.
>
> Then we commit txn in first connection,
> the result of second connection wii be:
>
> pg_get_viewdef
> ----------------
> SELECT a3.c +
> FROM a3;
> (1 row)
>
> old definition but using new relation name.
>

Reproduced here on HEAD. I also reproduce this with `begin transaction
isolation level serializable;`, so this is likely not an isolation
issue...

--
Best regards,
Kirill Reshke