The pg_shdescription system catalog table stores optional descriptions (comments) for shared database objects. Descriptions can be manipulated with the COMMENT command and viewed with psql’s \d meta-commands. See also pg_description, which performs a similar function for descriptions involving objects within a single database. Unlike most system catalogs, pg_shdescription is shared across all databases of a HAWQ system: there is only one copy of pg_shdescription per system, not one per database.

Table 1. pg_catalog.pg_shdescription

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
description text   Arbitrary text that serves as the description of this object.