Re: [SQLObject] How to use connection hub

[Ian B. <ia...@co...>]

Eduardo Elgueta wrote:
> Hi All,
> 
> I have a common set of tables (SQLObject classes) to be shared across 
> Wabware applications (system users, logs, system parameters, etc). 
> Besides these, I have an 'abstract' SQLObject class that knows how to 
> log, check permissions, etc. In this module, I have no connection 
> object/variable.
> 
> For every application, I have a specific set of SQLObject classes. In 
> this case, I've tried using the classical __connection__ variable and 
> setting sqlobject.sqlhub.threadConnection.
> 
> In the application login page, I set sqlobject.sqlhub.threadConnection.
 >
> The problem I have is it's behaving erraticaly. Sometimes I get a 'No 
> connection defined for this process or thread' exception. Other times, I 
> get a 'Table doesn't exist' exception (because the SQLObject instance is 
> using a wrong connection). Usually (not always) the first application 
> (the first to be used) works ok, and the rest have this unpredictable 
> behaviour. If I refresh the page (F5) it works ok, but sometimes I have 
> to wait a while (3 to 5 minutes). Sometimes it doesn't get it right 
> until I restart WebKit.

Hmm... that's no good.  You aren't using __connection__ together with 
sqlhub, are you?  That could cause weirdness.  It sounds very odd.  Are 
you deleting the threadConnection in sleep()?  If you can figure out 
what's happening, maybe I can put a test in there to help future people 
avoid the problem.  (Like should threadConnection not allow 
reassignment, only deletion and fresh assignment?)

Oh, wait, now I see -- you are doing it in the login page.  Which means 
the thread that served the login page has a thread connection, but the 
others don't.  And sometimes you hit that thread when you make a 
request, and sometimes you don't.

You need to set the threadConnection in every awake(), and remove it in 
every sleep().  And actually it shouldn't use connectionFromURI, now 
that I think about it -- you should be keeping a single instance of the 
connection around.  This is something you should put in your SitePage.

> Is there any way to fix the connection for an application? Every webware 
> application is a thread or a process, or neither? What approach can I 
> try in my situation?

You can use processConnection if all threads share a connection (i.e., 
you aren't using transactions).

-- 
Ian Bicking  /  ia...@co...  / http://blog.ianbicking.org