Re: do separate databases have any impact each other?

"TJ O'Donnell" <tjo(at)acm(dot)org> writes:
> While writing installation instructions for my new PostgreSQL product, I found myself
> writing the following sentence:
> "For first time users, we recommend building the gnova database,
> since it has no impact on other databases."

> Is this really true?

Reasonably.

> When a session ends that had opened my database, do all traces of it disappear,
> except its life on disk? How about .so's it might have caused to be loaded?

.so's only get loaded into sessions that have used them (unless you go
out of your way to persuade the postmaster to preload them).

AFAIK the only serious reason why someone might not want a playpen
database added to an existing installation is that any instability
at the C-code level propagates to the whole cluster --- that is,
a core dump in your .so takes out backends in other databases too.
The prevention for this is to make a separate cluster with its
own postmaster.

(Playpen code can have other bad side-effects, of course, such as
hogging all your CPU or I/O bandwidth. But a separate cluster
doesn't help that --- only putting it on a different machine does.)

regards, tom lane