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 HAWQ system.

Table 1. pg_catalog.pg_description

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 integer   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.