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From "Geir Magnusson Jr." <>
Subject Re: performance questions - faster Introspector
Date Mon, 10 Sep 2001 09:09:55 GMT
Two points on this :

1) If you have a big installation, and you share one instance of Velocity
across all of your webapps via Tomcat's lib, you are asking for trouble, I
think.  I can't see much benefit to that other than desire to avoid multiple
copies of the jar.  If that is the case, and you want to keep your webapps
partitioned, then use the separate instance runtime (which I think you are
doing, Bojan).  If *that* is the case, then I think you are safe, as nothing
is a singleton in the separate instance, your servlet holds the reference to
it, and when your servlet is recycled on the classloader change, then you
let go of the refrerence to the vel runtime, and get a new one.  All is

2) I still think we are adding unnecessary complexityh re the
per-classloader dumping.  KISS.


On 9/9/01 9:29 PM, "Attila Szegedi" <> wrote:

> Hmm. So, if I'm right you'd be happier with per-classloader dumping of
> cache? (I have this already coded, but have phased it out in agreement with
> Geir in spirit of the KISS principle).
> Attila.
> ----- Original Message -----
> From: "Bojan Smojver" <>
> To: <>
> Sent: 2001. szeptember 10. 8:32
> Subject: Re: performance questions - faster Introspector
>> "Geir Magnusson Jr." wrote:
>>> On 9/9/01 6:09 PM, "Paulo Gaspar" <> wrote:
>>>> Attached is a little modification to Attila's great work on the
>>>> Introspector.
>>>> I just gave it a little twist by keeping everything keyed by Class
>>>> instead of by class name. To do it was necessary to add an extra
>>>> map, but this one only gets to be used when there is a new class or
>>>> when a Class Loader got dumped.
>>> Note, for simplicity, we are going to knock out the 'by classloader'
> stuff
>>> and just dump the whole pile.
>> If Tomcat lib/apps installation of Velocity is used, then the
>> Introspector cache for all apps would be cleaned out since there would
>> be only one of those caches hanging around. In other words, if there are
>> many applications within one Tomcat, one has to be careful about
>> deployment of new classes as that might cause jerks on heavily loaded
>> servers.
>> Hmm, OK, promise to deploy only during the graveyard shift :-)
>> Bojan

Geir Magnusson Jr.
System and Software Consulting
Developing for the web?  See
If you look up, there are no limits - Japanese Proverb

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