Thread

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

Aya Iwata (Fujitsu) <iwata.aya@fujitsu.com> — 2024-11-20T05:11:07Z

Hi developers,

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

OS: 
Linux

Build options:
--prefix=/xxx/xxx/xxx' '--with-ssl=openssl' '--without-icu

Build and install command:
make all
make install

Reproduction procedure:

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()

Regards,
Aya Iwata
Fujitsu