On 4/13/15 6:21 AM, Anil Menon wrote:
In addition to all these comments
- If you use multiple databases, if you want to keep some "common"
tables (example counties_Table, My_company_details), its going to be a pain
- if you want to access tables across databases - you might need to
start using FDWs (which is going to be a administrative pain - syncing
passwords and stuff)
- you could set up security easier with multiple schemas - example userA
can only use schema A and no access to other schemas
Please don't top-post.
On Mon, Apr 13, 2015 at 4:48 PM, Pavel Stehule <pavel.steh...@gmail.com
<mailto:pavel.steh...@gmail.com>> wrote:
2015-04-13 10:43 GMT+02:00 Albe Laurenz <laurenz.a...@wien.gv.at
<mailto:laurenz.a...@wien.gv.at>>:
Michael Cheung wrote:
> I have many similar database to store data for every customer.
> Structure of database is almost the same.
> As I use same application to control all these data, so I can only use
> one database user to connect to these database.
> And I have no needs to query table for different customer together.
>
> I wonder which I should use, different shema or different database to
store data?
>
> I 'd like to know the advantage and disadvantage for using schema or
database.
In addition to what others have said:
If you use multiple schemas within one database, the danger is
greater that
data are written to or read from the wrong schema if your
application has a bug
ans does not make sure to always set search_path or qualify
every access with a
schema name.
With multiple databases you are guaranteed not to access data
from a different
database.
The main downside that I see to multiple databases is the
overhead: each of
the databases will have its own pg_catalog tables.
It can be advantage - if your schema is pretty complex - thousands
procedures, tables, then separate pg_catalog can be better - there
are issues with pg_dump, pg_restore.
So it depends on catalog size and complexity.
Two things no one has mentioned. First, you could also use row-level
security. If you plan on each customer having a fairly small amount of
data, this is by far your most efficient option. Anything else will
result in either huge catalogs or a lot of wasted catalog space.
Second, if you do per-database, that makes it trivial to scale across
multiple servers.
Regarding backups; you can easily do partial either way with pg_dump;
there's really no difference. You can't do partial with PITR, but that's
true for both schema and database.
--
Jim Nasby, Data Architect, Blue Treble Consulting
Data in Trouble? Get it in Treble! http://BlueTreble.com
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