Charles Anthony wrote:
Hi,Never mind! ;-)
Hello,
OK! It is a bit clearer for me, thanks. Each time I want to use a broker I should do:
broker = PersistenceBrokerFactory.defaultPersistenceBroker(); //I use the broker broker.close();
Yes, this is the way it should be done.
Is it better to do this EACH time I use the broker or ask for a broker one time (when the application start) and close after (all) the use?
It is better to do it each time.
If this is an "issue" for you, I suggest you look at using ODMG; it hides all broker usage from your application.
About the MAX number of broker in OJB.properties, is it a good way to set this number to 100 or even 1000?
Finally what is the exact meaning of this 2 log messages: "Already created persistence broker instances: x"? "Already created connections: 3 returning: ..."?
I'm afraid I don't know precisely..
PersistenceBroker instances and connections are "decoupled" and OJB use a pool for PB instances and does (by default) pool the connections.
>> "Already created persistence broker instances: x"? Number of created PB instances
>> "Already created connections: 3 returning: ..."? Number of overall created connections
regards, Armin
Cheers,
Charles.
Thanks for your help Sylvain
-----Message d'origine----- De: Charles Anthony [mailto:[EMAIL PROTECTED] Date: lundi, 27. octobre 2003 11:27 �: 'OJB Users List' Objet: RE: problem with PB instances creation
Hi,
at line 27, you should repeat lines 9-13.
At line 10 PersistenceBrokerFactory.defaultPersistenceBroker() asks the pool
for a broker, creating one *if* *necessary*. broker.close releases some resources from the broker, and returns the
broker to the pool.
In other words, after you close the broker, you can no longer use it. You
must get another broker.
If you really need to know how many (active) brokers there are in the pool,
you should be able to do
PersistenceBrokerFactoryDefaultImpl factory = (PersistenceBrokerFactoryDefaultImpl) PersistenceBrokerFactoryFactory.instance(); int brokersInPool = factory.activePersistenceBroker();
Cheers,
Charles
-----Original Message-----
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED]
Sent: 27 October 2003 10:17 To: [EMAIL PROTECTED]; [EMAIL PROTECTED] Subject: RE: problem with PB instances creation
Hello Thomas,
Is there a way to check how many instances are contained in
the pool?
You can find an example below.
You create a broker instance in line 10, right?
You use the broker instance first time in line 19. After this use you close() the instance.
But the problem is if you do the close() in line 25 when you use the broker for the second time in line 29 you have a ConnectionNotInProgressException.
Do I have to create a second broker? Or do I have to call a broker from the pool? How?
Thanks for your help Sylvain
1 public class MyExample {
2
3 private PersistenceBroker broker;
4
5 public void test() {
6 /**
7 * Persistence Broker
8 */
9 try {
10 broker = PersistenceBrokerFactory.defaultPersistenceBroker();
11 } catch (Throwable t) {
12 t.printStackTrace();
13 }
14
15 Criteria crit = new Criteria();
16 ...
17
18 try {
19 broker.beginTransaction();
20 //query 1...
21 broker.commitTransaction();
22 } catch (Throwable t) {
23 broker.abortTransaction();
24 } finally {
25 broker.close();
26 }
27
28 try {
29 broker.beginTransaction();
30 //query 2...
31 broker.commitTransaction();
32 } catch (Throwable t) {
33 broker.abortTransaction();
34 } finally {
35 broker.close();
36 }
37 }
38 }
-----Message d'origine----- De: Thomas Mahler [mailto:[EMAIL PROTECTED] Date: vendredi, 24. octobre 2003 18:17 �: OJB Users List Objet: Re: problem with PB instances creation
Hi Sylvain,
[EMAIL PROTECTED] wrote:
Hello,
I'm using OJB in my web application and I have some problem
with PB instances creation.
Each time I want to read/write data from/to my database I
create a PB intance:
broker = PersistenceBrokerFactory.defaultPersistenceBroker();
The problem is that lot of PB instances are created and
never destroyed.
I can see that in logs: "Already created persistence broker
instances: x".
For that I close the broker instance each time: broker.close();
But I have noticed that this function doesn't destroy the
PB instance.
So what is the job of this function?
broker instances are not destroyed, because it's expensive
to create
them. Thus OJB is pooling broker instances.---------------------------------------------------------------------
broker.close() simply makes the instances unavailable for further calls and puts the instance back to the pool.
How to destroy PB instance and prevent that the number of
PB instances is equal to the maximum?
If you close broker instancecs always after usage the number of active broker instances (i.e. brokers that are borrowed from the pool) equals the number servlet instances requesting a broker.
You can change the broker pool behaviour through settings in OJB.properties:
# specifies the behaviour of the pool when broker capacity is # exhausted (see maxActive above) # 0 - fail # 1 - block # 2 - grow whenExhaustedAction=0
The default setting is 0, so the pool throws an exception if an instance is requested when the pool is exhausted.
By setting this value to 2 the pool would simply grow and a new broker instance.
By setting it to 1 you can avoid growing of the pool, the application is blockes until an instance is available from the pool.
cheers, Thomas
Thanks for any help Sylvain
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