[Zope] Database Adapter - concurrent sessions?

[Tino Wildenhain]

Hi,

On Tue, 2004-10-19 at 11:44, Hermann Himmelbauer wrote:
> Hi,
> By adding a Database Adapter I can access my relational database.
> 
> What I would like to know is if one database adapter supports multiple 
> sessions, e.g. two scripts can query the database at the same time and not 
> sequentially.
> 
> If yes, is there a way to limit concurrent sessions because in my database 
> (MaxDB) I define a maximum number of user processes - if the number exceeds, 
> I get an error message, this should be prevented by somehow queuing database 
> connections that exceed a defined number.

Dont know for MaxDB, but most if not all postgres DAs are fully thread
save which means they are ready for concurrent access which happens
quite often in web applications. Usually ZopeDAs open as many 
connections per connection-object as there are threads configured.

Your Database has to offer 
number-of-zope-instances*number-of-threads*number-of-connection-objecs
possible connection at the same time.

Regards
Tino