The pg_description system catalog table stores optional descriptions (comments) for each database object. Descriptions can be manipulated with the COMMENT command and viewed with psql’s \d meta-commands. Descriptions of many built-in system objects are provided in the initial contents of pg_description. See also pg_shdescription, which performs a similar function for descriptions involving objects that are shared across a Greenplum system.

    column type references description
    objoid oid any OID column The OID of the object this description pertains to.
    classoid oid pg_class.oid The OID of the system catalog this object appears in
    objsubid int4 For a comment on a table column, this is the column number. For all other object types, this column is zero.
    description text Arbitrary text that serves as the description of this object.

    Parent topic: System Catalogs Definitions