Re: Schema and Namespace Oid confusion

ZongtianHou <zongtianhou@icloud.com> writes:
> First, what is the difference between namespace and schema?

None.

> Second, why the Oid of public namespace is 2200, the same between databases? Does oid is unique for every object
acrosscluster?  

CREATE DATABASE physically clones the template database, so all objects
have the same OIDs they had in the template.  OID uniqueness is only
expected for objects within one database (and even then, only across
objects in the same system catalog), not across the whole cluster.

            regards, tom lane