2010/10/27 Craig Ringer <craig@xxxxxxxxxxxxxxxxxxxxx>
On 27/10/10 04:49, Dmitriy Igrishin wrote:> <mailto:tonyceb@xxxxxxxxxxxxxx>>
> Hey Tony,
>
> 2010/10/27 Tony Cebzanov <tonyceb@xxxxxxxxxxxxxx
>It's potentially a fair bit more than that. It requires a new connection
> Â Â On 10/23/10 11:01 AM, Craig Ringer wrote:
> Â Â > Yep. As for not explicitly mentioning "lower" roles when granting a
> Â Â > higher role (ie "admin" isn't also a "user") - role inheritance.
>
> Â Â I knew about role inheritance, I just didn't know about the
> Â Â pg_has_role() function for determining if a user has a role. ÂThat's
> Â Â helpful, but I really don't want to be hitting the database with a
> Â Â pg_has_role() call for every time I want to check if a user should have
> Â Â access to a certain page or function in my application.
>
> Why not? Performance? It's just one function call.
(tcp connection, backend startup, auth, etc) or borrowing one from a
pool. If the Âpool is server side there's still a tcp connection with
the associated latency. Then there's a round trip for the query and
result. Processing the result. etc. It's not trivial, especially if your
client and server aren't co-located.
This applies to any arbitrary SQL command. I don't see the problem here.
Caching the privileges on the client side - is a good idea, but there is a
perennial problem that I see very clearly - cache invalidation.
Caching the privileges on the client side - is a good idea, but there is a
perennial problem that I see very clearly - cache invalidation.
Like you, I'd suggest using information_schema for the job.
--
Craig Ringer
Tech-related writing: http://soapyfrogs.blogspot.com/
--
// Dmitriy.
