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From Steve Poole <spoole...@googlemail.com>
Subject Re: Round tripping entity identity
Date Tue, 22 Sep 2009 10:31:09 GMT
On Mon, Sep 21, 2009 at 9:52 PM, Alois Reitbauer <
alois.reitbauer@dynatrace.com> wrote:

> Steve, others,
>
> we at dynaTrace are using the current JVMTI/JVMPI APIs where weg et the
> "tags" for each object. Those tags are necessary because of current API
> restrictions. However this approach is not practical for big dumps as
> you at least require a long to identify one object. For large heaps (>
> 1.5 GB) this will result in massive memory overhead.
>
> yes - understand that.


> I am by the way more than convinced that we will also need a spec for
> another native API that just for one that supports reading dumps. Tools
> like others cannot rely on the dump creation capabilities of JVMs for a
> number of reasons. If you want I can elaborate more on that.
>
> Yes please -  understanding the restrictions of existing technologies is
really important.


> - Alois
>
> -----Original Message-----
> From: Steve Poole [mailto:spoole167@googlemail.com]
> Sent: Dienstag, 08. September 2009 06:11
> To: kato-spec@incubator.apache.org
> Subject: Round tripping entity identity
>
> It's important for performance and scalability reasons that the API does
> not
> force the loading of a complete dump into memory.
>
> What that means in practise is that the application using the API will
> need
> to be able to read entities in a "random access" manner.  That in turn
> means
> that we need a mechanism that can provide a "handle" to an entity and a
> way
> for the API to convert the handle back into an full representation of
> the
> entity in question.
>
> Since the handle will probably have to be stored outside of Java (ie in
> a
> database)   the handle has to  be a primitive data type.
>
> Is this a reasonable view?
>
> The MAT tool is the only example I have to date where this mechanism is
> needed  -  I believe they use a long rather than a String.
>
> Are there other uses we should consider?  -  What about cross dump
> corrolations?
>
> Cheers
>
> Steve
>

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