Q: why EJBQLs run cyclic slowly

[veranda]

Hi,

Our environment is: JBOSS-3.2.2RC3 on RedHat Linux.

We iterate through a Collection of 3-4000 Entity Beans and for each of these we load a linked Entity Bean(using CMP). Most of the Entities is loaded in 20-40 miliseconds, but about every 35-45th bean is loaded in 700-1000 ms.
Considering that about 3-4000 beans could be loaded in the memory in the cycle, solving this problem would be a big performance gain.

Is cyclic loading latency normal? How could we reduce it?
Any help is appreciated very much.
If any logs or settings is needed, we can provide it.

Thanks,
Szucs Alina

[aloubyansky]

Basing on the given information I could suggest to upgrade to 3.2.4 and tune caching and preloading (read-ahead).

[cslenkey]

Dear Alex,

I would like to respond to your message. Veranda is one of my collegaues who is out of office today.
We have tried the 3.2.4RC2 and we could not use it.
I have opend a topich about our problem why we could not use 3.2.4:
http://jboss.org/index.html?module=bb&op=viewtopic&t=49936

Shortly: the new versions of JBoss genereates different SQL code.
Oracle RDBMS can not interpret SELECT DISTINCT with FOR UPDATE and this is understandable. 3.2.2RC3 generates the same SQL code without FOR UPDATE clause, so our application runs fine in this version.

If we are able to run our applcation on 3.2.4 we can tune the cache size and policy as you recommended.