Default database named postgres on Postgresql server

Question

Apparently there is a database \"postgres\" that is created by default on each postgresql server installation. Can anyone tell me or point me to documentation what it is use

Answer 1

It appears that it does not really have a well-defined purpose. According to the docs:

Creating a database cluster consists of creating the directories in which the database data will live, generating the shared catalog tables (tables that belong to the whole cluster rather than to any particular database), and creating the "template1" and "postgres" databases.

[...]

The postgres database is a default database meant for use by users, utilities and third party applications.

(Source: http://www.postgresql.org/docs/current/app-initdb.html )