> > Some time ago, we did some research about speeding up binary
> > serialization for remoting and we found out that the .NET 1.x codebase was
> > faster than the .NET 2.0 codebase. After profiling the code, it turned out
> > that the generic dictionary objects were slowing things down. Replacing
them
> > with hashtables made it equal again (or .net 2.0 became slightly faster).
> > Looking deeper into it, the GetObjectData routines differ. When I made a
> > Dictionary class which had a similar GetObjectData routine as Hashtable,
> > namely serializing the keys and values as object arrays, it was solved.
>
> Okay, good to know. If I ever need it, I'll time it myself :)
:). It's one of those gotcha's one will only run into when performance
is critical. :). After a while you'll then realize that the whole binary
formatter is dead slow and implement your own serialization classes (which
write to a byte array, caching redundant objects etc.) and this whole issue is
moot ;) (A bit offtopic perhaps, but see Simon Hewitt's articles on code
project about this subject:
http://www.codeproject.com/dotnet/FastSerializer.asp
and
http://www.codeproject.com/dotnet/OptimizingSerialization2.asp
Once you dig into this, there's no end in sight apparently, but it's good to
know for remoting users that there is a way to speed things up ;). We worked
with Simon to get our remoting code as fast as possible and with compact block
sizes. )
> > The Order of the items isn't important for hashtables/dictionaries,
> as
> > the order isn't defined: you can't pull the data out in a given order.
>
> Well, you can enumerate over the items, keys, and values (and do
> CopyTo), and I guess one _could_ expect a deserialized Dictionary to
> enumerate in the same order as the original one unless explicitly told
> it isn't so.
One could use the enumerator indeed, but if I add an item, is it
always appended to the list? IMHO undefined. The Dictionary<T,U> docs say:
"For purposes of enumeration, each item in the dictionary is treated as a
KeyValuePair structure representing a value and its key. The order in which
the items are returned is undefined."
So it's undefined what order the items are returned. :)
FB
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