I have following script, which initialize two clusters: echo CREATE ROLE new_user WITH LOGIN;>init_cluster.sql echo CREATE DATABASE new_database WITH OWNER = new_user;>>init_cluster.sql initdb -D case1 -U postgres pg_ctl start -D case1 -w psql "host=localhost dbname=postgres user=postgres"<init_cluster.sql pg_ctl stop -D case1 -m smart -w initdb -D case2 -U postgres postgres --single -D case2 postgres<init_cluster.sql In case1 I have following oid assigned: new_user: 16384 new_database: 16385 In case2: new_user: 15062 new_database: 15063 And pgAdmin does not show new_database in the server tree. Documentation says following: >OIDs assigned during normal database operation are constrained to be 16384 or higher. This ensures that the range 10000—16383 is free for OIDs assigned automatically by genbki.pl or during initdb. Is such difference in oid assignment in Single-User Mode expected?