I absolutely agree with you that at the end of each transaction the beans
state has to be written to the database, no discussion about that.
I think what we were talking about is to bypass reloading of bean state at
the START of transaction if the bean is already cached. I think you should
be able to do that if you can guarantee that nobody else can modify the data
in the database without going through the entity bean. And if you can
guarantee that, you can then set the flag in deployment descriptor and the
cached state of the bean will become reusable without reloading it from
database.
Do you think that is possible?
Miro Halas
-----Original Message-----
From: Philippe Durieux [mailto:[EMAIL PROTECTED]]
Sent: Thursday, August 02, 2001 8:35 AM
To: Halas, Miroslav
Cc: 'Ilker Sozat'; [EMAIL PROTECTED]
Subject: Re: how to tune jonas for performance problems
"Halas, Miroslav" wrote:
>
> Weblogic has a configuration parameter on a datasource (or a bean, I don't
> remember it correctly) to mark it as 'shared'. Shared means that there is
> other application which is modifying database and therefore beans has to
be
> reread at the beginning of transaction. If the bean/datasource is not
marked
> as shared than the cached copy is used.
>
> Can something like this be implemented in Jonas? What would be the best
> place to put it in?
>
> Miro Halas
>
Hi Miro,
I think that your proposal is not correct. When you work with transactions,
you MUST insure that the bean state is written at the end of each
transaction,
regardless if someone else is using it or not.
What is possible with jonas is only to share entity beans if you don't use
transactions. In that case, the bean state is kept only in memory until a
special event occur (end of server, timeout, start of transaction, ...).
This is effective only for beans declared as "Reentrant".
Philippe
> -----Original Message-----
> From: Ilker Sozat [mailto:[EMAIL PROTECTED]]
> Sent: Sunday, July 29, 2001 12:46 PM
> To: [EMAIL PROTECTED]
> Subject: how to tune jonas for performance problems
>
> Hi,
>
> I am having some performance problems (and a memory leak problem), and I
am
> not sure whether I have tuned jonas for optimized performance (before
having
> to change my design in less maintainable ways). My two basic questions
> related to performance are:
>
> 1) Is there a way in Jonas to prevent entity beans in the cache to be
reread
> at the beginning of a transaction? I have a session bean which reads a
> subset of the entity beans at each method call (more or less the same
> subset). If those beans are already in the cache, and if only this
> application is modifying the database, it is really unnecessary to do an
> additional read for each and every bean in that subset (for a
> findByPrimaryKey() method). Having a cache large enough for this subset
and
> using jeremie for intracalls would be the best optimization I can hope to
> get from jonas.
>
> 2) I am keeping track of any changes in my entity bean and make ejbStore
an
> empty method if there isn't any. Also, I am only updating the modified
data
> since the ejb is representing info from 5 different tables. Does using the
> isModified() attribute still bring an advantage over this?
>
> My memory leak problem is that 15 simultaneous users continuously calling
an
> addBean() method (which basically does as the name implies) brings down
the
> server in 2 days. The final error I'm getting is something like "panic
could
> not create LWP". I have increased the max memory size, and the file
> descriptor limit from 64 to 1024. Increasing file descriptor limit moved
the
> time to crash the system from a couple of hours to 2 days, but I feel it
is
> still a problem. I do not cache, or keep any references between calls. Is
> this a known issue (btw, I am using RMI on Solaris 2.6, and planning to
> change to jeremie, and I am really hoping that it is related to the way
rmi
> manages the connections) ?
>
> thanks,
> ilker
>
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--
Philippe Durieux ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Bull - 1 rue de Provence - 38432 Echirolles Cedex France
[EMAIL PROTECTED]
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