Summary
The catalog pg_namespace stores namespaces. A namespace is the structure underlying SQL schemas: each namespace can have a separate collection of relations, types, etc. without name conflicts.
(Description quoted from the official PostgreSQL documentation.)
Columns
The pg_namespace system catalog exposes the following columns (names, types and descriptions are taken verbatim from the PostgreSQL documentation):
oidoid
Row identifiernspnamename
Name of the namespacenspowneroidreferencespg_authid.oid
Owner of the namespacenspaclaclitem[]
Access privileges; see ddl_priv for details
Related catalogs
This object references the following other system catalogs:
nspowner→pg_authid
Version applicability
Present in PostgreSQL 17, 18, 19 (verified against each release’s documentation). This is a long-standing system object that also exists in earlier PostgreSQL releases.
Related & references
Reference: PostgreSQL documentation — pg_namespace.