MDBs and Sessions
We have an MDB that listens to a queue. When a message is received the data is passed to a StatefullSessionBean for processing. Now this works seemingly fine for a single message, but if we publish many "simultaneous" messages to the queue we get Session Timeouts at the MDB. We thought this was because of the default 1 thread implementation in OC4J and decided to set initialThreads to 50. This seemed to alleviate the session timeout error, but now the problem we're getting is of course that we aren't allowed to call the same StatefulSessionBean from another thread. In summary:
What we're getting:
All the MDB instances seem to be sharing the same context, i.e. a lookup on the StatefulSessionBean returns the same reference, and fails when using multiple threads.
What we'd like:
For each distinct message that is passed to our MDB to create a new Session that can have it's own reference to a StatefulSessionBean.
We could resolve the issue by making the StatefullSessionBean a webservice or such and call that instead, creating a new session as such, but this is absolutely not what we want to do. Does anyone know of a good way to achieve our goal, e.g. some configuration option in OC4J or just a plain explanation on how it is supposed to be done?
Nobody have any idea about this? It must be a common enough problem with MDB's?
Similar Messages
-
EJB - MDB and Session and Entity - Seem to always run under same Thread
I am working on an application that implemets a connection from an MDB to a Session EJB which inturn connects to a Entity EJB. All connections are impemented as Local Home. I use log4j for tracing and notice that the thread ID reported for all activity is the same "Thread ID: MessageListenerThreadPool : 0" .
This confuses me because I thought that all EJB's would execute under different threads. Have I done something wrong? Have I missinterpreted the EJB implementation? Any opinions would be greatly appreciated!!Hi Kelly,
This is a slight misinterpretation of the EJB threading requirements. There are a couple different issues as play here. First, the main threading guarantee made by the spec is that a particular instance of an EJB will not be invoked by the container on more than one thread at a time. This is one of the guarantees that simplifies the EJB programming model so that developers don't have to do anything special (e.g. the use of synchronized blocks) to handle concurrent access. Second, the EJB Local programming model requires that invocations have pass-by-reference semantics. Of course, the easiest way for the container to provide that behavior is to literally make the local invocation on the same thread.
The call-flow you're describing touches a single instance from three different beans, so the threading guarantee is not violated. Hope that clears things up a bit.
--ken -
Ok,
I am bit confused with how exactly MDBs work with Transactions.
For example,
suppose we have a simple standalone java message producer which sends a message to a Queue. A MDB's onMessage() picks it up.
Let's say the MDB makes some updates to the database and then invokes a method on a stateless session bean which also updates a database.
By default the transaction attribute of the MDB and stateless session bean would be REQUIRED.
If the stateless session bean database update fails, I presume the MDB's database updates also get rolled back.
But, does the message get rolled back? If not when would the message be rolled back?
Does it make any difference if the MDB is a topic or a queue? Does it make any difference if the message producer is a standalone client or
a stateless session bean with it's own transactional behaviour?
Any help appreciated.
Thanks.The general principle is: if you have a MDB which consumes a message in a transaction, and that transaction is rolled back, then the message is "rolled back". This means that it is put back on the queue or topic. It will then be delivered to the MDB again.
If your MDB calls a session bean then the two can share the same global transaction as you suggest.
Note however that the transaction which consumes the message is completely separate from any transaction which placed the message on the queue in the first place. JMS completely decouples the two steps. Once the message is added to the queue the producer is irrelevant.
Nigel -
Problem with application item and session state
Okay, let's see if I can explain this problem coherently.
I have a small app (one page), with an application item, F_WHERE_CLAUSE.
This page has three regions in which there are items that the users can populate for search conditions. A couple of these items are "select list with submit" (I still need to upgrade to the AJAX method, I know). There is another region which has one hidden field, called P1_WHERE_CLAUSE. This field is defined to "Always, replacing any value in session state..." with source type of "Item (application or page.....", and a source value of F_WHERE_CLAUSE with no default value.
I have a button called "Search" which submits the page and fires a PL/SQL process which builds a where condition based upon the other page items and stores the value to the application item F_WHERE_CLAUSE (correctly).
For testing, I've made the P1_WHERE_CLAUSE field visible so that I can see what's going on. I've also clicked the debug and session buttons to help trace this. After I click the "Search" button and the page submits, debug shows:
0.02: ...Session State: Save "P1_WHERE_CLAUSE" - saving same value: "1=1"
followed later by:
0.05: ...Session State: Saved Item "F_WHERE_CLAUSE" New Value="lower(primary_class) = 'rock' and country = 'Spain'"
The field P1_WHERE_CLAUSE displays with the correct search criteria as signified by F_WHERE_CLAUSE above. However, If I click the "session" button to view the session state values, P1_WHERE_CLAUSE shows up as:
P1_WHERE_CLAUSE Textarea 1=1 U while F_WHERE_CLAUSE displays the correct value still.
The reason this "problem" came up, is that this page also has three SQL report regions which use &P1_WHERE_CLAUSE. for the where condition. While they display the correct results on-screen, each report region also has the "Export to csv" enabled, and the export seems to be using the "1=1" condition (from the "session" window) instead of the search criteria that the on-screen region is using (F_WHERE_CLAUSE and the displayed P1_WHERE_CLAUSE), resulting in a retreival of all records.
Anybody have any idea what's going on and why, and how to get the csv export to use the correct value for the where condition?
Thanks,
Bill FergusonIt appears the "Export to CSV" functionality requires the item value to be set in session state. The P1_WHERE_CLAUSE item value never gets saved to session state. The page is rendered and the value is put in the item on the page but until you submit the page session state doesn't know what P1_WHERE_CLAUSE is.
Create a before header computation or process to set the value of P1_WHERE_CLAUSE (which will save it to session state). It is interesting that the report regions didn't need to look at the value in session state but the "export to csv" does.
--Jeff -
How to get the job logs from sm35 by using the queue id and session name?
hi all,
can any one please let me know how to read the job log from sm35 by using the session name and queue id. i have the job name and job count but is it possible to download the job log by using the queue id and session name.
FYI..
i want to read this job log and i want to send it to an email id.
-> i am using the job_open and submitting the zreport via job name and job count and then i am using the function module job_close.
but this is not working in my scenario i have the queue id and session name by using this two i want to get the job log is there any function module available or code please provide me some inputs.
thanks in advance,
koushikHi Bharath,
If you want to download it to the local file then you can follow the instructions in the below link.
How to download Batch Input Session Log?
Regards,
Sachin -
Session.putValue() and session.setAttribute
do I have to use session.putValue() before using session.setAttribute() and session.getAttribute() ?
becuase I have one JSP page include one form (action=TheSameJspFile.JSP) several Submit bottuns each Bottun has its Value.
in the JSP I request the submit value and depends on it doing stuff ...
each Value I have to get and to set a session Attribute, if I want to putValue it will delete the old value.
how can I solve this?You need to store something in the session before you can retrieve it.
So, you need to do a setAttribute() to place something in the session. Then you use getAttribute() to retrieve it. DO NOT use putValue as it is deprecated and has been replaced by setAttribute(). DO NOT use getValue() as it is deprecated and has been replaced by getAttribute(). -
How to create bdc for fbs1 using both call transaction and session
Hi Friends,
i have one problem with tcode FBS1, i need to create a bdc program for both call transaction and session method using subroutine.
first call transaction needs to execute if there is an error sesion has to execute. if u have code please forward.
thanks in advance.
chandramouli pothuguntawhere as in call transaction we can do error handling explictly.those errors are stored in one file .this file will send to the error log(session method),i.e session log.
in the above case we use both call transaction n session method at time in one program.sample code is below ,go through it .
data : begin of itxk01 occurs 0,
end of itxk01.
data : bdcdata like itbdcdata occurs 0 with header line.
data : itbdcmsgcoll like itbdcmsgcoll occurs 0 with header line,
itxk01 like itxk01-dup occurs 0 with header line.
call gui-upload.
loop at itxk01.
refresh itxk01.
perform bdc-dynpr0 using 'prg' 'scr'
perform bdc-dynfld using fnam fval
call transaction 'xk01' using bdcdata mode 'a' update 's' messages into itbdcmsgcoll.
if sy-subrc ne 0.
append itxk01 into itxk01-dup.
endif.
endloop.
if not itxk01-dup[] is initial.
refresh itck01.
call bdc_open_group
itxk01 = itxk01-dup.
loop at itxk01.
refresh itxk01.
perform bdc-dynpr0 using 'prg' 'scr'
perform bdc-dynfld using fnam fval
call bdc-insert.
endloop.
call bdc-close-group.
form bdc-dynpr0 using pr sc
endform .
form bdc-field using fnam faval
endform.
this will help u.
reward points for me
kiran -
I'm trying to use an XA topic connection factory in my MDB, I was getting a "not supported in this release" error until I added this annotation to my MDB:
@MessageDrivenDeployment(
resourceAdapter = "myProviderInstance"
But now my MDB is no longer dequeuing messages.
I found the following in the docs (http://download-west.oracle.com/docs/cd/B31017_01/web.1013/b28221/undejdev010.htm#CCHGGHAE)
--- BEGIN QUOTE FROM ORACLE DOCS ---
If you use @MessageDrivenDeployment, you can configure message service options using nested @ActivationConfigProperty annotations or using @MessageDrivenDeployment attributes: @ActivationConfigProperty configuration overrides @MessageDrivenDeployment attributes.
If you use @MessageDriven, you can configure message service options using nested @ActivationConfigProperty annotations only.
If you configure using @MessageDrivenDeployment attributes, your application can only access a message service provider without a J2CA resource adapter. If later you decide to access your message service provider using a J2CA resource adapter, your application will fail to deploy. If you configure using nested @ActivationConfigProperty annotations, your application can access a message service provider with or without a J2CA resource adapter. Oracle recommends that if you configure using annotations, you should use the @ActivationConfigProperty approach.
Example 2-6 shows both a @MessageDrivenDeployment and @MessageDriven annotation using @ActivationConfigProperty annotations for message service configuration. Note that the DestinationName activation configuration property in the @MessageDrivenDeployment annotation overrides that in the @MessageDriven annotation.
Example 2-6 @MessageDriven and @MessageDrivenDeployment Annotation for a J2CA Message Service Provider
import javax.ejb.MessageDriven;
import oracle.j2ee.ejb.MessageDrivenDeployment;
import javax.ejb.ActivationConfigProperty;
import javax.jms.Message;
import javax.jms.MessageListener;
@MessageDriven(
activationConfig = {
@ActivationConfigProperty(
propertyName="DestinationName", propertyValue="OracleASjms/MyQueue"
@MessageDrivenDeployment(
activationConfig = {
@ActivationConfigProperty(
propertyName="DestinationName", propertyValue="OracleASjms/DeployedQueue"
@ActivationConfigProperty(
propertyName="ResourceAdapter", propertyValue="OracleASjms"
--- END QUOTE FROM ORACLE DOCS ---
So, instead of specifying the resource adapter as I had above, I simply pasted the last bit of annotations from the docs into my MDB, and much to my surprise I learned that you can't have an activationConfig in a @MessageDrivenDeployment
What's the solution?OK, I got a little further. Everything works now as such
I'm using the XA topic connection factory, I'm using the resource adapter.
BUT, when I set the transaction required attribute on the MDB, I no longer receive messages.
No errors are logged anywhere. Any suggestions? -
Upload file with iframe loos session user and session id in wwv_flow_files
Hello every one, hope someone could help us with this problem.
What we are trying to do is to upload a file from a jquery dialog in a appex page by redirecting the POST action of the wwvFlowForm to the iframe.
*1. In the javascript there is the function call to open my modal window with the input*
function add_fichier_form(numeroProjet,idCat){
$("#div_upload_fichier").dialog(
modal : true ,
autoOpen : false ,
resizable: false ,
width: 700
$('#div_upload_fichier').parent().appendTo('#div_base');
$('#upload_button').unbind('click').click(function(){
if ($('#P4010_FILE_FICHIER').val() != '') {
$('#upload_iframe_v2').unbind('load').load(function () {
$('#upload_status').html(' déplacement du fichier...');
// move the file
$('#upload_status').html('Fichier transféré avec succès');
//file transfer ok
//calling the javascript function to add everything in my own table;
//we see the file in the wwv_flow_file_objects$ without
add_fichier_form_db();
// set the form target to the iframe, submit, then remove the target
$('#wwvFlowForm').attr('target','upload_iframe_v2').submit().removeAttr('target');
$('#upload_status').html(' Téléchargement du fichier...');
}else {
alert('Veuillez sélectionner un fichier');
$("#div_upload_fichier").dialog("option", "title", "Ajout d'un fichier");
$("#div_upload_fichier").dialog("open");
}*2. At this point we see the file in the table but without the user and session credential*
select *
from wwv_flow_file_objects$
The result is that the field security_group_id is assign to 0 AND created_by = APEX_PUBLIC_USER
*3. add_fichier_form_db(); the javascript function making the ajax call to a procedure plsql*
function add_fichier_form_db(){
//alert ('Dasn fichier form db');
vNumeroProjet = document.getElementById('P4010_CAT_NUMERO_PROJET').value;
vIdCat = document.getElementById('P4010_CAT_ID').value;
vFichierNom = document.getElementById('P4010_NOM_FICHIER').value;
vFichierDesc = document.getElementById('P4010_DESC_FICHIER').value;
vFichierFile = document.getElementById('P4010_FILE_FICHIER_NAME').value;
var ajaxRequest = new htmldb_Get(null , 300, 'APPLICATION_PROCESS=ADD_FICHIER_FORM_DB', 4010);
ajaxRequest.add( "P4010_CAT_NUMERO_PROJET", vNumeroProjet);
ajaxRequest.add( "P4010_F_CAT_ID", vIdCat);
ajaxRequest.add( "P4010_FICHIER_NOM", vFichierNom);
ajaxRequest.add( "P4010_FICHIER_DESC", vFichierDesc);
ajaxRequest.add( "P4010_FILE_FICHIER_NAME", vFichierFile);
var gReturn = ajaxRequest.get();
if (gReturn){
$x("getlistfichier").innerHTML = gReturn;
closeForm();
}else{
alert ('Problèmes dans le call Ajax ADD_REPERTOIRE_FORM_DB \n La valeur retournée est: \n' + gReturn);
}*4. PLSQL PROCEDURE *
h1. WHEN the query is executing it's return ORA-01403: no data found. WHY ????
PROCEDURE P_ADD_FICHIER_FORM_DB(
P_NUMERO_PROJET number,
P_CAT_ID number,
P_FICHIER_NOM varchar2,
P_FICHIER_DESC varchar2,
P_FILE_FICHIER_NAME in varchar2)
AS
vNumeroProjet number;
vFichierNom varchar(255);
vFichierDesc varchar(2000);
vCatId number;
vActif number;
vDocSize number;
vNomUsager varchar(10);
vDateCreation date;
vFichierTypeId number;
vNomReel varchar2(1000);
vNomReel2 varchar2(1000);
vCurVal number;
BEGIN
SELECT FILENAME,DOC_SIZE,CREATED_ON
INTO
vNomReel,vDocSize,vDateCreation
FROM WWV_FLOW_FILES
WHERE FILENAME = P_FILE_FICHIER_NAME;
/*GET ERROR sqlerrm:ORA-01403: no data found */
END P_ADD_FICHIER_FORM_DB;h4. hope someone help us soon
Thanks in advance
jocelynFinally we find what was wrong so i give you the solution.
In the javascript on the function add_fichier_form
We need to append the div of the form to the default form of apex wwvFlowForm
so the line*
$('#div_upload_fichier').parent().appendTo('#div_base');
should be change to*
$('#div_upload_fichier').parent().appendTo('#wwvFlowForm');Edited by: jocbed on 2012-01-26 11:08 -
Business delegate and Session facade design patterns
Does any one tell me, what is the difference between business delegate and session facade design patterns.
1. Session Facade decouples client code from Entity beans introducing session bean as a middle layer while Business Delegate decouples client code from EJB layer ( Session beans).
2. SF reduces network overhead while BD reduces maintenance overhead.
3. In SF any change in Session bean would make client code change.
While in DB client is totally separate from Session bean because BD layer insulate client from Session beans(EJB layer).
3. In only SF scenario, Client coder has to know about EJB programming but BD pattern no EJB specialization needed.
4.SF emphasizes on separation of Verb, Noun scenario while BD emphasizes on separation of client(presentable) and EJB layer.
Anybody pls suggest more differences ? -
Error in CALL TRANSACTION and SESSION Method
I have 8 records (1,2,3,4,5,6,7,8) to update into SAP database using CALL TRANSACTION and SESSION Method. If there is a error in 6th record. What happens in both call transaction and session method.
Please let me know which records will process and what about the error record. How to process only the error record if all other records have updated into database.Hi Patil_sumeet,
if your code for this is not protected secret of some federal agency, you may read [How to post code in SCN, and some things NOT to do...|How to post code in SCN, and some things NOT to do...; and then post relevant lines here.
According to the facts presented until know it may have been better to ask Radio Eriwan
Regards
Clemens -
Hi,
I have questions about "Accounting-Start" and "Accounting-Stop".
1.If a NAS configured to have a primary and a backup RADIUS server. To start with all the “Accounting-Start” records will be in the primary RADIUS server. Later on the primary server goes down (Primary server won’t tell the NAS?). When sessions stop, the NAS sends the “Accounting-Stop” to the secondary. I understand the “Start-Stop” record with the same “user name” and “session-id” ideally should be recorded in the same server. If this situation happens what should both the NAS and RADIUS server do?
2.A NAS configured to have a primary and backup RADIUS server. To start with all the “Accounting-Start” records will be in the primary RADIUS server. Later on the administrator decided to change the primary server (as there are problems with the previous primary). sessions stop, the NAS sends the “Accounting-Stop” to the new primary. This ends up the “Accounting-Start” and “Accounting-Stop” with the same “user name” and “session Id” in two RADIUS servers.
To summarize, how to avoid the ”start-stop” pair ends up in different servers ? If it does, is it an issue for RADIUS application ?
Cheers,
1.If a NAS configured to have a primary and a backup RADIUS server. To start with all the “Accounting-Start” records will be in the primary RADIUS server. Later on the primary server goes down (Primary server won’t tell the NAS?). When sessions stop, the NAS sends the “Accounting-Stop” to the secondary. I understand the “Start-Stop” record with the same “user name” and “session-id” ideally should be recorded in the same server. If this situation happens what should both the NAS and RADIUS server do?
2.A NAS configured to have a primary and backup RADIUS server. To start with all the “Accounting-Start” records will be in the primary RADIUS server. Later on the administrator decided to change the primary server (as there are problems with the previous primary). sessions stop, the NAS sends the “Accounting-Stop” to the new primary. This ends up the “Accounting-Start” and “Accounting-Stop” with the same “user name” and “session Id” in two RADIUS servers.
To summarize, how to avoid the ”start-stop” pair ends up in different servers ? If it does, is it an issue for RADIUS application ?
Cheers,vignesh and BalusC,
following is the code in front controller's doFilter method. is this not thread safe?
HttpServletRequest req = (HttpServletRequest) request;
HttpServletResponse res = (HttpServletResponse) response;
HttpSession session = req.getSession();
somepackage.User user;
if(session.getAttribute("user") == null){
user = new somepackage.User();
session.setAttribute("user", user);
}else{
user = (somepackage.User) session.getAttribute("user");
}user object maintains all information about a user. if it is in session scope, everything should work fine.
another observation is after some time of usage, both people in different systems are getting same session.getId()
in my logout page i am using
session.invalidate();
thanks,
moses -
No of minuts in McuJoinsAndLeaves and session tables ????
Hi All,
I am trying to find out the No. of minutes in McuJoinsAndLeaves table(lcscdr DB) and session table(Qoeetrics DB) are exactly same or not..?? if no. of minutes are same in both table............please tell me conditions ????
Thanks
BrijWhich column did you refer to?
Please compare these two tables according to the following link.
McuJoinsAndLeaves Table
http://technet.microsoft.com/en-us/library/gg398316.aspx
Session Table
http://technet.microsoft.com/en-us/library/gg398635.aspx
In my lab, I didn’t see the same data from these two tables.
Lisa Zheng
TechNet Community Support -
Oracle db 11g r2 Configuration of processes and session
I recently installed Oracle DB 11g R2 and 50,000 users connect to this database suggest me what would be basic configurations .
Processes and sessions parameters for database are 5000 and 5505 but it is little lagging now so if its possible i want to make it maximum of processes and sessions or automatic .50,000 users getting connected concurrently? How many users/sessions remain active at any given point of time?
For such high userbase/sessions better to go with share server configuration, since I cannot assume that even 10% of the users will be active at any given point of time so better to use shared servers and dispatchers. -
Service Locator and session facade pattern
What are differences between Service Locator and session facade pattern?
For me it seems one and the same.
Please explain me in detail. Expecting kind help.
Thanks,
Rahul
Edited by: rahulb1 on Feb 26, 2008 5:07 PMrdoekes wrote:
The ServiceLocator Pattern is a singleton which hold a map of used DataSources. The idea is that you perform a lookup once and use the cache afterwards. The session facade is just one DataSource lookup.huh? Those J2EE patterns are not really reduced to datasources and the SessionFacade has actually nothing to do with datasources.
Session Facade
It has Facade in it and a Facade is usually used to give a simple entrypoint by providing a standartized interface. The same is now with the Session Facade. You have a Session bean that represents a high-level business component that interacts and calls lower-level business components.
Imagine having client a accessing 5 business objects with the remote calls, which is not an efficient way (network latency) or accessing the SessionFace and the session face is doing all the work through local access.
Service Locator
As J2EE components are using JDNI to lookup for ejb interfaces,DataSources, JMS components, connections etc. isntead of writing all the lookup in many code piecess across the project, you write a service locator that gives you a centralized place to handle the lookup's. It's easier to maintain and to control such a setup.
As you can see there's quite a big difference ;-)
cya,
Nail
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