[silva-dev] Silva Metadata: support for delegates?
crobbenhaar at web.de
Mon Apr 4 10:52:50 CEST 2005
> I'm still not sure whether this merge does not actually defeat the orignal goal
> for the getMetadataValue method: to be as quick as possible. But there might be
> some problem with this method for other reasons anyway. So, let's review the
> current state.
Oh, I admit I did not take this into account ...
In case there is no object delegator set up. the extra code boils down to:
bind_data = annotations and \
delegate = bind_data.get(ObjectDelegate)
# not reached here
a) check if the "annotations" are not None -- here I could be more explicit and
hence cheaper ... I do not think the "annotations" object could have
an expensive __nonzero__ method, if it exist, but maybe it does ...
b) do a key access ("annotations[MetadataNamespace]") on an object of type
"Annotations" (which is just a PersistentMapping in disguise).
c) ... and a "get(BindingRunTime)" on the returned Annotations object
(again a PersistentMapping).
I guessed this is not so expensive, as there is a similar call a few
d) finally this does again a non-optimal boolean comparison instead of
checking for None and then again a get on a PersistentMapping
Beside of the optimizations in a) and d) now obvious to me after being
pointed to, I am not certain about the performance impact.
Is there any code to check the performance of that method,
or am I expected to write my own stuff for it? I can try to do, but I am
not sure if I get the point where performance issues kick in.
Did the performance issue only happend with large sites (e.g. due to ZODB
cache size issues), or can this reproduced with a small test site, too?
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