Re: Databases Vs. Schemas

From: Adam Ruth <aruth(at)intercation(dot)com>
To: "Subbiah, Stalin" <SSubbiah(at)netopia(dot)com>
Cc: "'pgsql-admin(at)postgresql(dot)org'" <pgsql-admin(at)postgresql(dot)org>, "'pgsql-performance(at)postgresql(dot)org'" <pgsql-performance(at)postgresql(dot)org>
Subject: Re: Databases Vs. Schemas
Date: 2004-03-23 13:54:02
Message-ID: 8B012B25-7CD1-11D8-85EE-000A959D1424@intercation.com
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We have a similarly sized database and we went with schemas. We did
something different, though, we created one schema that contained all
of the tables (we used the public schema) and then created the hundreds
of schemas with views that access only the related rows for a
particular schema. Something like this:

create table public.file (siteid int, id int, [fields]);
create schema sc1;
create view sc1.file as select * from public.file where siteid = 1;
create schema sc2;
create view sc2.file as select * from public file where siteid = 2;

And we also created rules to allow update, delete, and insert on those
views so that they looked like tables. The reason we did this is
because we ran into issues with too many open files during pg_dump when
we had thousands of tables instead of about 1 hundred tables and
thousands of views.

We, however, did have a need to periodically select data from 2 schemas
at a time, and it was simpler logic than if we needed 2 database
connections.

Adam Ruth

On Mar 22, 2004, at 2:30 PM, Subbiah, Stalin wrote:

> --sorry to repost, just subscribed to the list. hopefully it gets to
> the
> list this time --
>
> Hi All,
>
> We are evaluating the options for having multiple databases vs.
> schemas on a
> single database cluster for a custom grown app that we developed. Each
> app
> installs same set of tables for each service. And the service could
> easily
> be in thousands. so Is it better to have 1000 databases vs 1000
> schemas in a
> database cluster. What are the performance overhead of having multiple
> databases vs. schemas (if any). I'm leaning towards having schemas
> rather
> than databases but i would like to get others opinion on this.
> Appreciate
> your reply.
>
> Thanks,
> Stalin
>
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