[Seaside] Transactions, database connections, indices,
GOODS and Seaside
avi at beta4.com
Fri May 14 02:59:55 CEST 2004
On May 13, 2004, at 5:24 PM, C. David Shaffer wrote:
> Thanks guys. I'm using GOODS right now and each session registers the
> active DB in a dynamic variable during request processing.
I'm not sure what your usage patterns are for GOODS, but unless you're
opening a new connection for every request (which would be pretty
inefficient), I don't see why this wants to be a dynamic variable - any
given session should always use the same connection. You might be able
to share one connection between several sessions, with appropriate
mutexing, but I definitely wouldn't want to switch connections halfway
through a session, because the object identities would be all wrong.
Or am I missing something?
> use: (1 to: 100) atRandom
> during: [super responseForRequest: aRequest]
> but this code only results in a single value for SCCurrentTransaction
> for each session. Why is that? It certainly doesn't fit with a view
> of dynamic scope sans continuations. Is this a subtly caused by
> continuations or error handling that messes up the dynamic binding
It's a subtlety of continuations. You will probably find that it isn't
exactly one value per session, but rather per component or task - a
#call: is likely to change the value. This makes sense if you think
about it - you have to be using the same stack for the duration of a
task's #go method. There's a new call to #responseForRequest: every
time, of course, but then you jump back into the old stack.
It's an interesting point, though, and one I hadn't fully thought
through until now. I guess it means that the correct pattern for
dynamic variables is to store them in the session, and then have
^ WACurrentSession value currentTransaction
It may be worth making that a standard part of Session...
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