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help / color / mirror / Atom feedFrom: Pierre Forstmann <pierre.forstmann@gmail.com>
To: Benjamin Leis <benleis1@gmail.com>
Cc: pgsql-admin@lists.postgresql.org
Cc: sonicmonkey@gmail.com
Subject: Re: what is the difference between ROLE clause and IN ROLE clause for CREATE USER statement ?
Date: Wed, 2 Sep 2026 20:31:05 +0200
Message-ID: <6c814776-0a02-4b31-9a5e-ab281fa9e4fe@gmail.com> (raw)
In-Reply-To: <CADP9qHt-VxrnznQ5DyVK6DpC39HuBOY1FSRkO_TH5UOETzZnBQ@mail.gmail.com>
References: <cc3ebec7-0690-4924-a644-9d0d708e1635@gmail.com>
<CADP9qHt-VxrnznQ5DyVK6DpC39HuBOY1FSRkO_TH5UOETzZnBQ@mail.gmail.com>
I have asked chatgpt which says:
/CREATE USER ur ROLE pg_maintain; -- pg_maintain is a member of ur
CREATE USER uri IN ROLE pg_maintain; -- uri is a member of pg_maintain
/
/which creates following role hierarchy:/
/ur
↑
pg_maintain
↑
uri/
/
/
/and *only |uri| is below |pg_maintain| in the membership hierarchy, so
|uri| inherits |pg_maintain|'s maintenance privileges.*/
/That is exactly why |vacuumdb -U uri| succeeds while |vacuumdb -U ur|
skips the catalogs./
Even if know that roles and users are almost the same entities in PG, I
find this confusing.
Thanks.
Le 02/09/2026 à 07:52, Benjamin Leis a écrit :
> I think create in role makes the user a member of the specified role.
> While create role makes the roles members of this new user group. So
> it's a question of which is the container and what is being contained.
>
> On Tue, Sep 1, 2026, 10:16 PM Pierre Forstmann
> <pierre.forstmann@gmail.com> wrote:
>
> Hello,
>
> I don't understand the difference even after reading CREATE
> USER/CREATE
> ROLE documentation.
>
> Here is a scenario that shows a difference with PG 18.6 (built
> with pgenv):
>
> pierre=# create user ur role pg_maintain;
> CREATE ROLE
> pierre=# create user uri in role pg_maintain;
> CREATE ROLE
> pierre=# \du
> List of roles
> Role name | Attributes
> -----------+------------------------------------------------------------
> pierre | Superuser
> postgres | Superuser, Create role, Create DB, Replication,
> Bypass RLS
> ur |
> uri |
>
> pierre=# \l
> List of
> databases
> Name | Owner | Encoding | Locale Provider | Collate |
> Ctype | Locale | ICU Rules | Access privileges
> -----------+----------+----------+-----------------+-------------+-------------+--------+-----------+-----------------------
> pierre | pierre | UTF8 | libc | en_US.UTF-8 |
> en_US.UTF-8 | | |
> postgres | postgres | UTF8 | libc | en_US.UTF-8 |
> en_US.UTF-8 | | |
> template0 | postgres | UTF8 | libc | en_US.UTF-8 |
> en_US.UTF-8 | | | =c/postgres +
> | | | | | |
> | | postgres=CTc/postgres
> template1 | postgres | UTF8 | libc | en_US.UTF-8 |
> en_US.UTF-8 | | | =c/postgres +
> | | | | | |
> | | postgres=CTc/postgres
> (4 rows)
>
>
> pierre@alma:~$ vacuumdb -U ur
> vacuumdb: vacuuming database "pierre"
> WARNING: permission denied to vacuum "pg_proc", skipping it
> WARNING: permission denied to vacuum "pg_attribute", skipping it
> WARNING: permission denied to vacuum "pg_description", skipping it
> WARNING: permission denied to vacuum "pg_collation", skipping it
> WARNING: permission denied to vacuum "pg_statistic", skipping it
> WARNING: permission denied to vacuum "pg_type", skipping it
> WARNING: permission denied to vacuum "pg_class", skipping it
> WARNING: permission denied to vacuum "pg_rewrite", skipping it
> WARNING: permission denied to vacuum "pg_operator", skipping it
> WARNING: permission denied to vacuum "pg_depend", skipping it
> WARNING: permission denied to vacuum "sql_features", skipping it
> WARNING: permission denied to vacuum "pg_amop", skipping it
> WARNING: permission denied to vacuum "pg_constraint", skipping it
> WARNING: permission denied to vacuum "pg_amproc", skipping it
> WARNING: permission denied to vacuum "pg_ts_config_map", skipping it
> WARNING: permission denied to vacuum "pg_index", skipping it
> WARNING: permission denied to vacuum "pg_init_privs", skipping it
> WARNING: permission denied to vacuum "pg_opclass", skipping it
> WARNING: permission denied to vacuum "pg_aggregate", skipping it
> WARNING: permission denied to vacuum "pg_cast", skipping it
> WARNING: permission denied to vacuum "pg_opfamily", skipping it
> WARNING: permission denied to vacuum "pg_conversion", skipping it
> WARNING: permission denied to vacuum "pg_namespace", skipping it
> WARNING: permission denied to vacuum "sql_implementation_info",
> skipping it
> WARNING: permission denied to vacuum "pg_am", skipping it
> WARNING: permission denied to vacuum "pg_language", skipping it
> WARNING: permission denied to vacuum "pg_authid", skipping it
> WARNING: permission denied to vacuum "pg_database", skipping it
> WARNING: permission denied to vacuum "pg_tablespace", skipping it
> WARNING: permission denied to vacuum "pg_auth_members", skipping it
> WARNING: permission denied to vacuum "pg_shdescription", skipping it
> WARNING: permission denied to vacuum "pg_ts_config", skipping it
> WARNING: permission denied to vacuum "pg_ts_dict", skipping it
> WARNING: permission denied to vacuum "pg_ts_parser", skipping it
> WARNING: permission denied to vacuum "pg_ts_template", skipping it
> WARNING: permission denied to vacuum "pg_extension", skipping it
> WARNING: permission denied to vacuum "pg_range", skipping it
> WARNING: permission denied to vacuum "sql_parts", skipping it
> WARNING: permission denied to vacuum "sql_sizing", skipping it
> WARNING: permission denied to vacuum "pg_shdepend", skipping it
> WARNING: permission denied to vacuum "pg_transform", skipping it
> WARNING: permission denied to vacuum "pg_sequence", skipping it
> WARNING: permission denied to vacuum "pg_subscription", skipping it
> WARNING: permission denied to vacuum "pg_publication", skipping it
> WARNING: permission denied to vacuum "pg_publication_namespace",
> skipping it
> WARNING: permission denied to vacuum "pg_publication_rel",
> skipping it
> WARNING: permission denied to vacuum "pg_subscription_rel",
> skipping it
> WARNING: permission denied to vacuum "pg_foreign_data_wrapper",
> skipping it
> WARNING: permission denied to vacuum "pg_foreign_server", skipping it
> WARNING: permission denied to vacuum "pg_policy", skipping it
> WARNING: permission denied to vacuum "pg_replication_origin",
> skipping it
> WARNING: permission denied to vacuum "pg_default_acl", skipping it
> WARNING: permission denied to vacuum "pg_inherits", skipping it
> WARNING: permission denied to vacuum "pg_seclabel", skipping it
> WARNING: permission denied to vacuum "pg_shseclabel", skipping it
> WARNING: permission denied to vacuum "pg_user_mapping", skipping it
> WARNING: permission denied to vacuum "pg_trigger", skipping it
> WARNING: permission denied to vacuum "pg_event_trigger", skipping it
> WARNING: permission denied to vacuum "pg_statistic_ext_data",
> skipping it
> WARNING: permission denied to vacuum "pg_statistic_ext", skipping it
> WARNING: permission denied to vacuum "pg_enum", skipping it
> WARNING: permission denied to vacuum "pg_attrdef", skipping it
> WARNING: permission denied to vacuum "pg_largeobject_metadata",
> skipping it
> WARNING: permission denied to vacuum "pg_foreign_table", skipping it
> WARNING: permission denied to vacuum "pg_parameter_acl", skipping it
> WARNING: permission denied to vacuum "pg_db_role_setting",
> skipping it
> WARNING: permission denied to vacuum "pg_partitioned_table",
> skipping it
> WARNING: permission denied to vacuum "pg_largeobject", skipping it
> pierre@alma:~$ vacuumdb -U uri
> vacuumdb: vacuuming database "pierre"
> pierre@alma:~$
>
>
> Thanks.
>
>
>
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Message-ID: <6c814776-0a02-4b31-9a5e-ab281fa9e4fe@gmail.com>
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To: pgsql-admin@postgresql.org
Cc: pierre.forstmann@gmail.com, benleis1@gmail.com, pgsql-admin@lists.postgresql.org, sonicmonkey@gmail.com
Subject: Re: what is the difference between ROLE clause and IN ROLE clause for CREATE USER statement ?
In-Reply-To: <6c814776-0a02-4b31-9a5e-ab281fa9e4fe@gmail.com>
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