Re: 'WARNING: you don't own a lock of type ExclusiveLock' is printed during the GRANT command on PostgreSQL16.5

On Wed, Nov 20, 2024 at 05:11:07AM +0000, Aya Iwata (Fujitsu) wrote:
> During our tests on November release,
> we discovered a "WARNING: you don't own a lock of type ExclusiveLock" that occurred at a strange time in GRANT command.
>
> [Details]
> Version:
> 16.5

> 1. Set binaries bin and lib path
> 2. Initiate the server using initdb command
> 3. create folder for tablespace
> 4. start the server usaing pg_ctl command
> 5. execute the following commands:
>
> This is only possible when psql executes each command individually.
> $ psql -d postgres -c "CREATE USER nmluser1;"
> CREATE ROLE
> $ psql -d postgres -c "CREATE TABLESPACE test_tblspace LOCATION '/xxx /xxx/pgsql16.5/tbs';"
> CREATE TABLESPACE
> $ psql -d postgres -c "CREATE DATABASE enc_testdb;"
> CREATE DATABASE
> $ psql -d postgres -c "GRANT ALL PRIVILEGES ON DATABASE postgres TO nmluser1;"
> GRANT
> $ psql -d postgres -c "GRANT ALL PRIVILEGES ON DATABASE enc_testdb TO nmluser1;"
> GRANT
> $ psql -d postgres -c "GRANT CREATE ON TABLESPACE test_tblspace TO nmluser1;"
> WARNING:  you don't own a lock of type ExclusiveLock
> GRANT
>
>
> [Investigated]
> - This WARNING did not occur when tested with FEP16.4 using the same "Reproduction procedure:"
> - This WARNING did not occur when running CREATE ROLE through GRANT in a single session connected to psql.
> - Also, it did not happen when running 'psql -f' with an .sql file
> - We have run similar tests in the November releases of v12 through v17, but this is not reported by the tester in those releases.
> -- Therefore, we have not tried this "Reproduction procedure:" on versions other than 16.5 and 16.4.
> - This WARNING message appears in several places, and after modifying the source code to know which elog it is,
> seemed to come from ReleaseSysCache() in ExecGrant_common()

Thanks for the report. This seems reasonably likely to come from a defect in
commit 51ff46d. I will look into it.