<pbj@xxxxxxxxxx> writes: >>> On 12/23/2015 04:17 PM, Paul Jones wrote: >>> This isn't the best characterization...the "postgres" data is not a "system" database but rather a convenient default user database. Maybe I'm being overly picky here but seeing "system" in this context does have a connotation that we really don't want to impart onto the "postgres" database. > This was one of the big lessons I learned from this. All this time I was > under the mistaken impression that it was special. FWIW, there really aren't any special databases in a Postgres installation. As Paul already explained, "postgres" exists mainly to provide a convenient default landing point for utility applications. The only thing magic about it is the name --- you can drop it, and create a new database with that same name, and be none the worse for wear. Or do without, if you don't mind specifying a different landing point. The other two created-by-default databases, template0 and template1, are similarly not really hardwired in. template1 is hardwired to the extent that CREATE DATABASE operates by copying whatever database is named "template1" (in the absence of a different TEMPLATE option). That's about it. There is a convention that template0 should be an absolutely unmodified virgin copy of the state created by initdb, but it's only a convention not something that the core database code either enforces or depends on. Now, if you were to try to drop either of those databases, you'd get a Bronx cheer: regression=# drop database template1; ERROR: cannot drop a template database regression=# drop database template0; ERROR: cannot drop a template database but that's only driven by the fact that pg_database.datistemplate is set for them (and that flag does little more than allow nonprivileged users to select them as sources for CREATE DATABASE). If you were up against the wall in trying to reconstitute a broken installation, you could manually unset the datistemplate flag for either, drop it, and clone it from the other one. In short, there's less magic here than meets the eye. regards, tom lane -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
