Multi-Threading Standalone Application as Backgroup OS Process
Hi Fellas
I have written a Standalone Server Application which when run in background (using the following command) doesnt run any of the Threads at all.
./scheduler &
Whereas when this application when run in foreground i.e. without & (ampersand) at the end, it works fine.
The application spawns configurable number of thread and all the threads periodically wait for job to be put in the job queue. One thread arbitrarily picks one job and runs it.
Does someone know the mystery? I am supposed to run this on HP/UX where I am having this problem. Just tried on SunOS ... same behaviour here as well.
Guyz help me asap as we are a day away from the deployment in production. I never thought about this.
Thanks in Advance
Saleem
Hi Chuck
Well the process without Threads is nothing. The process (application) kicks off Threads and then those Threads execute jobs and all.
I am not sure whether this is caused by SIGHUP. I am not familiar much with these signals and all. Please help me understand this.
Yes I tried 'nohup' as follows:
nohup ./scheduler -vm cmd -env dev -d -t > screen_dump
when this command gets executed, I open another telnet window and tail 'screen_dump' file. After issuing the command above, prompt is not available so it doesnt seem to me like a bckground application. So when I kill/close that terminal window, the screen_dump file starts growing for some unknown (to me) reason.
I am definitely writing tons of stuff/traces to this 'screen_dump' file and the application waits for the user to key in commands like start, refresh, shutdown etc. Is this I/O blocking the whole application while in background?
Thanks for your reply. I look forward to hear from you.
Saleem
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Multi-threaded java application and deadlock down in Oracle library
Hello,
I was running our Java (JDK 1.6_14) application from Windows XP hitting an Oracle (10g) instance on Linux and came across a deadlock issue with two (of 10) threads. Below is the stacktraces (based on Java thread-dump at the command line). This code I've run 30-40 times with no problems of deadlocks.
The Oracle library that we're using for our Java application is ojdbc14.jar and sdoapi.jar (for spatial).
We create our Connection as follows (for each thread -- 10 of them):
public class Worker implements Runnable
private Connection _Conn;
public Worker(...)
DriverManager.registerDriver(new oracle.jdbc.driver.OracleDriver());
_Conn = DriverManager.getConnection(url, username, password);
_Conn.setAutoCommit(false);
The code that is already executing these same lines below was already executed by other threads (in their own instance of Worker). So this is very confusing.
Any ideas? Version of the .jar files? Place how we're calling "DriverManager.registerDriver(new oracle.jdbc.driver.OracleDriver());"?
Thanks, Jim
Found one Java-level deadlock:
=============================
"WORKER_1":
waiting to lock monitor 0x02b50d8c (object 0x22e8af80, a oracle.jdbc.driver.T4CConnection),
which is held by "WORKER_0"
"WORKER_0":
waiting to lock monitor 0x02b50d24 (object 0x22f6d258, a oracle.sql.StructDescriptor),
which is held by "WORKER_1"
Java stack information for the threads listed above:
===================================================
"WORKER_1":
at oracle.jdbc.driver.OraclePreparedStatement.executeQuery(OraclePreparedStatement.java:3410)
- waiting to lock <0x22e8af80> (a oracle.jdbc.driver.T4CConnection)
at oracle.sql.StructDescriptor.initMetaData1_9_0(StructDescriptor.java:1516)
- locked <0x22f6d258> (a oracle.sql.StructDescriptor)
- locked <0x22eabd80> (a oracle.jdbc.driver.T4CConnection)
at oracle.sql.StructDescriptor.initMetaData1(StructDescriptor.java:1408)
at oracle.sql.StructDescriptor.isInstantiable(StructDescriptor.java:892)
at oracle.sql.STRUCT.<init>(STRUCT.java:148)
at oracle.spatial.geometry.JGeometry.store(JGeometry.java:2954)
at oracle.spatial.geometry.JGeometry.store(JGeometry.java:3777)
.......... <our package/class>
"WORKER_0":
at oracle.sql.StructDescriptor.initMetaData1_9_0(StructDescriptor.java:1494)
- waiting to lock <0x22f6d258> (a oracle.sql.StructDescriptor)
- locked <0x22e8af80> (a oracle.jdbc.driver.T4CConnection)
at oracle.sql.StructDescriptor.initMetaData1(StructDescriptor.java:1408)
at oracle.sql.StructDescriptor.isInstantiable(StructDescriptor.java:892)
at oracle.sql.STRUCT.<init>(STRUCT.java:148)
at oracle.spatial.geometry.JGeometry.store(JGeometry.java:2954)
at oracle.spatial.geometry.JGeometry.store(JGeometry.java:3777)
..........<our package/class>
Edited by: Jim Atharris on Aug 24, 2009 6:23 PMThanks Toon for your reply.
Yes each Worker (executing in their own thread) has their own instance of Connection as per the Constructor (shown in original post). That is why this is weird.
I'll check the v$session when I get into work.
Based on our code that I put in the original email, Connection is a non-static variable. We have a per Thread per instance of Worker of which that Worker instance has its own instance of Connection. So I'm wonder if the following needs to occur:
Both of these lines (from original email) need to happen in the main thread as follows:
DriverManager.registerDriver(new oracle.jdbc.driver.OracleDriver());
for (i=0;i<NUM_OF_WORKERS)
_Conn = DriverManager.getConnection(url, username, password);
new Worker(_Conn);
Thanks,Jim -
Memory Leak in a multi threaded Swing application (ImageIcon)
When I profile my swing application with netbeans 5.5 , I notice that after each periodically tidy up my image container (add,remove IconImage objects to a hashmap or arraylist), there gather by and by surviving objects. This leads to run out of memory after a while. Is there any other way to avoid this effect?
Any ideas about "The JVM is notorious for caching images."
please help..
what I have made briefly:
1.) Read the binary stream from the db :
rs=stmt.executeQuery(query);
if(rs.next()){
int len=rs.getInt(2);
byte [] b=new byte[len];
InputStream in = rs.getBinaryStream(3);
try {
in.read(b);
in.close();
img=Toolkit.getDefaultToolkit().createImage(b);
} catch (IOException e) {
e.printStackTrace();
stmt.close();
rs.close();2.) hold the icon as field :
this.icon = new ImageIcon(img);3.) After a while I remove the object from my collection and on the
overridden method finalize() I also call the flush() method.
if(this.icon != null){
this.icon.getImage().flush();
this.icon = null;
}The surviving objects still increase?! On the page of SUN they
submitted a bug. But this is set on closed/fixed.
(http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=4014323)
What am I doing wrong? I also use the byte[] constructor on creating the icon and
my java version is 1.5.0_10.If in your JFrame u have placed your image, before invoke the dispose()
method put explicitly the image pointer to null and deregister all listener
you have added to any componentI implemented your suggest and after starting a long time test, in one hour there gathered aprox. 500 surviving generations. I attach a snapshot and the java file ( http://www.box.net/public/eqznamrazd ). The used heap size swings between 3MB and 5MB. I guess this wont kill so quickly the application but anyway there is something wrong!
Even properly closed streams, database connections etc.. Really despairing. Could one take a look to the java source?
some snippets bellow:
private class MyImageIcon extends ImageIcon {
public MyImageIcon(Image img){
super(img);
public void removeImage(Image anImage){
tracker.removeImage(anImage);
private class DetailDialog extends javax.swing.JFrame {
private String personnr;
private MyImageIcon icon;
public DetailDialog(String personnr,MyImageIcon icon){
this.personnr = personnr;
this.icon = icon;
public void dispose() {
if(icon != null){
icon.removeImage(icon.getImage());
icon.getImage().flush();
icon = null;
super.dispose();
private class Person extends Object {
private MyImageIcon icon;
private String number;
private DetailDialog detailDialog;
protected void destroy() {
if(icon!=null){
icon.removeImage(icon.getImage());
icon.getImage().flush();
icon = null;
if(detailDialog!=null){
detailDialog.dispose();
private Image LoadImageFromDB(String personnr){
Image img = null;
String filename = personnr + ".jpg";
Connection con = getMysqlConnection();
Statement stmt;
ResultSet rs;
try {
stmt = con.createStatement();
String query = "select * from personImage where image='"+filename+"'";
rs=stmt.executeQuery(query);
if(rs.next()){
int len=rs.getInt(2);
byte [] b=new byte[len];
InputStream in = rs.getBinaryStream(3);
try {
in.read(b);
in.close();
img =
java.awt.Toolkit.getDefaultToolkit().createImage(b);
} catch (IOException e) {
e.printStackTrace();
rs.close();
rs = null;
stmt.close();
stmt = null;
con.close();
con = null;
} catch (SQLException e) {
e.printStackTrace();
return img;
public void random(){
java.sql.ResultSet rs = null;
java.sql.Statement stmt=null;
java.sql.Connection con = getSybaseConnection();
try {
try {
stmt = con.createStatement();
rs = stmt.executeQuery(randomquery);
while(rs.next()){
Person person = new Person();
person.number = rs.getString("PersonNr");
Image img = LoadImageFromDB(person.number);
if(img !=null){
MyImageIcon ico = new MyImageIcon(img);
person.icon = ico;
person.detailDialog = new
DetailDialog(person.number,person.icon);
personList.add(person);
System.out.println("Container size: " +
personList.size());
counter++;
if(counter%20 == 0){
for(Person p : personList){
p.destroy();
personList.clear();
System.gc();//no need, but I force for this example
System.out.println("Container cleared, size: " +
personList.size());
} catch (SQLException ex) {
ex.printStackTrace();
}finally{
if(rs != null){
rs.close();
}if(stmt != null){
stmt.close();
}if(con != null){
con.close();
} catch (SQLException ex) {
ex.printStackTrace();
} -
Oraclient9i.dll error in multi threaded delphi server application
I created a multi threaded server application in delphi using oracle9i and indy server components. When I run my application, I am getting an error "oraclient9i.dll" error when executing my SQL statements. I have check communication between my server application and the client application without using oracle and its working fine, its only when I started executing SQL statements when I got this error.
Can anybody help me with this problem or point me to the right direction on how to resolve this issue.
thanks> I have tried what you suggested. I have created a
seperate TOracleSession on each thread that I create
on the OnConnect event however I am having Problems
using the oraclesession created on the OnExecute
event. Somehow it is still executing the SQL that I
have created on the main form where I first opened an
oraclesession component created on the main form.
It sounds then like the TOracleSession object in the thread is a copy of the one in the main thread/form.
> Do you think that It would work if I create an
instance of the TOracleDatasets and TOracleQuery on
the OnExecute event and also at the same time create
my TOracleSession on this event and continue
processing the data receive from the client server.
I've never used the Indy components for threading. The default TThread class worked just fine for me.
What I used to do is define the session and database objects as privates in my new thread class (let's call it TThreadSQL) - which was subclassed from TThread.
The constructor of this new TThreadSQL class did the following (writing here purely from memory - have not done Delphi for some time now): constructor TThreadSQL.Create( TNSalias, username, password : string );
// constructor is called with the Oracle session connection details
begin
inherited Create; // call the parent class constructor
CreateOracleSession; // call own private method to create an Oracle connection
end;
The CreateOracleSession method would then:
- create a BDE Session (TSession) object
- create a BDE Database (TDatabase) object, using the BDE Oracle native driver and an Oracle TNS alias plus username and password for connection
The destructor would close the connection. The Execute method which is used to fire up the thread, would use a TQuery object (or whatever) to execute a SQL using it owns connection. -
Multi-thread application recompile object with make but runs with old value
Hi. I am working on a simulation in Java, and there is some behavior going on that I cannot understand. Granted, I'm a mechanical engineer, not a CS student (a fact that is probably made obvious by the code I'm posting below). The simulation comprises three parts: a controller, a robot, and a 3-d sensor. Here's the code for the "Simulation" application.
class Simulation {
void go() {
ThreeDSensor sensorRunner = new ThreeDSensor();
VSController controllerRunner = new VSController();
KukaKR15SL robotRunner = new KukaKR15SL();
Thread sensorThread = new Thread(sensorRunner);
Thread controllerThread = new Thread(controllerRunner);
Thread robotThread = new Thread(robotRunner);
sensorThread.start();
try {
Thread.sleep(1000); // Give sensorThread time to start in order to catch first triggers
} catch(InterruptedException ex) {
ex.printStackTrace();
controllerThread.start();
try {
Thread.sleep(1000); // Give controllerThread time to open the socket for communication with robotThread
} catch(InterruptedException ex) {
ex.printStackTrace();
robotThread.start();
public static void main(String[] args) {
Simulation sim = new Simulation();
sim.go();
}I guess the big reason I'm using multi-threading is that once this simulation is working I want to be able to just run VSController alone and have it interface with a robot controller and a PC performing image processing. So with multiple threads I'm sending TCP and UDP messages around just like the final system will.
I have made an object for my VSController that just stores values used by the simulation. That way I could have them all in one place instead of hunting through methods to change them. One example is "double noiseThreshold". Quickly, here is the code for "ControllerSettings.java".
class ControllerSettings {
final double cameraXOffset = 0; // If > 0 then the origin of the camera CS is not on the center line of the lens
final double cameraYOffset = 0; // If > 0 then the origin of the camera CS is not on the center line of the lens
final double cameraZOffset = 700; // The distance that must be kept between the camera and the target
// Error magnitude less than this is disregarded (in centimeters if roundingData else in millimeters)
final double noiseThreshold = 60;
final boolean estimatingEndPoints = false; // If the controller is using two images per cycle then true
final boolean roundingData = false;
final boolean using3DData = true; // How double[] sent from Matlab image processing is used
* If the robot controller uses the output of this controller to command
* motions in cartesian space then true. This is used in two places: 1) initial guess of Jacobian,
* and 2) "commandType" element sent to robot controller.
final boolean useRobotControllerModel = false;
final double thetaBumpValueForEstimationOfJacobian = .1; // Distance each joint is jogged in estimation process
final double bumpDistance = 50; // Distance robot moves each time (magnitude of translation in mm)
final double limitAngular = .5; // Max amout robot joint will be commanded to rotate (in degrees)
}And here is some pertinent code from "VSController.java".
class VSController implements Runnable{
ControllerSettings cSettings; // Stores all the preferences used by the controller
NGN controller; // This is the controller algorithm.
int dof; // The degrees of freedom of the robot being controlled
KukaSendData ksd; // This provides communication to the robot.
protected DatagramSocket socketForVisionSystem = null;
ImageFeaturesData ifd; // This parses and stores data from the image system.
double[] errorVector; // This is what's acted on by the algorithm
PrintWriter errorTrackerOut = null; // For analysis of error vector
public void run() {
VSController vsc = new VSController();
vsc.go();
public void go() {
initWriters();
cSettings = new ControllerSettings();
public boolean isNoise() {
boolean ret = false;
double magnitude = 0;
for (int i = 0; i < errorVector.length; i++) {
magnitude += errorVector[i] * errorVector;
magnitude = Math.sqrt(magnitude);
if (magnitude <= cSettings.noiseThreshold) {
System.out.println("VSController: magnitude (of errorVector) = " + magnitude +
", threshold = " + cSettings.noiseThreshold); // Debug
Now here's my issue: I change the value for "noiseThreshold" in "ControllerSettings.java" then run make from terminal (makefile code posted below) and rerun "Simulation". However, despite my changes to "ControllerSettings.java" the value for "noiseThreshold" is not changed, as evidenced by the output on the terminal screen:VSController: magnitude (of errorVector) = 6.085046125925263, threshold = 10.0 See, that value of 10.0 is what I used to have for noiseThreshold. I do not know why this value does not update even though I save the java file and execute make in between executions of Simulation. I would love it if someone could explain this problem to me.
Here's the contents of makefile.
JFLAGS = -cp ../Jama\-1\.0\.2.jar:../utils/:/usr/share/java/vecmath\-1\.5\.2.jar:.
JC = javac
.SUFFIXES: .java .class
.java.class:
$(JC) $(JFLAGS) $*.java
CLASSES = \
ControllerSettings.java \
ImageFeaturesData.java \
KukaKR15SL.java \
../utils/KukaSendData.java \
NGN.java \
Puma560.java \
Robot.java \
RobotSettings.java \
Simulation.java \
SimulationSettings.java \
SixRRobot.java \
Targets.java \
TargetsSettings.java \
ThreeDData.java \
ThreeDSensor.java \
VSController.java
default: classes
classes: $(CLASSES:.java=.class)
clean:
$(RM) *.classEdited by: raequin on Apr 5, 2010 1:43 PMI saw this explanation about what's causing my problem.
"When the Java compiler sees a reference to a final static primitive or String, it inserts the actual value of that constant into the class that uses it. If you then change the constant value in the defining class but don't recompile the using class, it will continue to use the old value."
I verified that the value updates if I also change something in VSController.java, forcing it to recompile. I think I will solve this problem by just making the variables in ControllerSettings no longer final (and then recompile VSController to make sure it takes effect!). Is there another solution? I saw intern(), but that seems to only apply to Strings.
Thanks. -
Multi-Thread application and common data
I try to make a multi-Thread application. All the Threads will update some common data.
How could I access the variable �VALUE� with the Thread in the following code:
public class Demo {
private static long VALUE;
public Demo(long SvId) {
VALUE = 0;
public static class makeThread extends Thread {
public void run() {
VALUE++;
public static long getVALUE() {
return VALUE;
The goal is to get the �VALUE� updated by the Thread with �getVALUE()�
Thanks for your reply
BenoitThat code is so wrong in so many ways......
I know you're just experimenting here, learning what can and can't be done with Threads, but bad habits start early, and get harder to kick as time goes on. I am going to give a little explanation here about what's wrong, and what's right.. If you're going to do anything serious though, please, read some books, and don't pick up bad habits.
Alright, The "answer" code. You don't use Thread.sleep() to wait for Threads to finish. That's just silly, use the join() method. It blocks until the threads execution is done. So if you have a whole bunch of threads in an array, and you want to start them up, and then do something once they finish. Do this.
for(int k=0; k<threads.length; k++) {
threads[k].start();
for(int k=0; k<threads.length; k++) {
threads[k].join();
System.out.println("All Threads Done");Now that's the simple problem. No tears there.
On to the java memory model. Here where the eye water starts flowing. The program you have written is not guarenteed to do what you expect it to do, that is, increment VALUE some amount of time and then print it out. The program is not "Thread Safe".
Problem 1) - Atomic Operations and Synchronization
Incrementing a 'long' is not an atomic operation via the JVM spec, icrementing an int is, so if you change the type of VALUE to an int you don't have to worry about corruption here. If a long is required, or any method with more then one operation that must complete without another thread entering. Then you must learn how to use the synchronized keyword.
Problem 2) - Visiblity
To get at this problem you have to understand low level computing terms. The variable VALUE will NOT be written out to main memory every time you increment it. It will be stored in the CPUs cache. If you have more then one CPU, and different CPUs get those threads you are starting up, one CPU won't know what the other is doing. You get memory overwrites, and nothing you expect. If you solve problem 1 by using a synchronized block, you also solve problem 2, because updating a variable under a lock will cause full visiblity of the change. However, there is another keyword in java.. "volatile".. A field modified with this keyword will always have it's changes visible.
This is a very short explaination, barely scratching the surface. I won't even go into performance issues here. If you want to know more. Here's the resources.
Doug Lea's book
http://java.sun.com/docs/books/cp/
Doug Lea's Site
http://g.cs.oswego.edu
-Spinoza -
The problem about multi-thread in java application
i have problem with the multi-thread in java application, i don't know how to stop and restart a thread safely, because the function thread.stop(),thread.suspend() are both deprecated.
now what i can only do is making the thread check a flag(true or false) to determine whether to start or to stop, but i think this thread will always be in the memory and maybe it will lower the performance of the system, as the program i am developping is working under realtime enviorement.
please help me about it. thanks !hi,
you can stop a thread by exiting it's run()-method which in terms can be done by checking the interrupted-flag:
public void run(){
while(interrupted()){ //if the thread consists of a loop
or
public void run(){
if(interrupted())return;
if(interrupted())return;
or by the use of the return-statement anywhere withing the run-method. Afterwards, that is when the thread is no longer needed, you clear all the references to the specific thread object by setting them to null:
Thread t;
... //working
t.interrupt(); //interrupting
while(t.isAlive()){
Thread.yield(); //wait till thread t has stopped
t=null;
best regards, Michael -
Immutable Objects in multi threaded application - how does it works?
Hi
I have this code will work in multithreaded application.
I know that immutable object is thread safe because its state cannot be changed. And if we have volatile reference, if is changed with e.g.
MyImmutableObject state = MyImmutableObject.newInstance(oldState, newArgs); i.e. if a thread wants to update the state it must create new immutable object initializing it with the old state and some new state arguments) and this will be visible to all other threads.
But the question is, if a thread2 starts long operation with the state, in the middle of which thread1 updates the state with new instance, what will happen? Thread2 will use reference to the old object state i.e. it will use inconsistent state? Or thread2 will see the change made by thread1 because the reference to state is volatile, and in this case thread1 can use in the first part of its long operation the old state and in the second part the new state, which is incorrect?
Therad1: Thead2:
State state = cache.get(); //t1
Result result1 = DoSomethingWithState(state); //t1
State state = cache.get(); //t2
->longOperation1(state); //t1
Result result2 = DoSomethingWithState(state); //t2
->longOperation1(state); //t2
->longOperation2(state);//t1
cache.update(result1); //t1
->longOperation2(state);//t2
cache.update(result2);//t2
Result DoSomethingWithState(State state) {
longOperation1(state);
//Imaging Thread1 finish here and update state, when Thread2 is going to execute next method
longOperation2(state);
return result;
class cache {
private volatile State state = State.newInstance(null, null);
cache.update(result) {
this.state = State.newInstance(result.getState, result.getNewFactors);
get(){
return state;
}Please don't cross post
http://stackoverflow.com/questions/6803487/immutable-objects-in-multi-threaded-application-how-does-it-work -
Multi-threaded application crashing the VM
Hi,
I have a multi-threaded (about 120 threads) application which crashes without after running for a while.
I get this in the windows event viewer
Faulting application java.exe, version 0.0.0.0, faulting module kernel32.dll, version 5.2.3790.0, fault address 0x000017b1.
Anyone knows why this would happen?
- vineetHi Alexis,
Thanks for the response to my post!!
Which version of the JVM?C:\>java -version
java version "1.4.2_05"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.4.2_05-b04)
Java HotSpot(TM) Client VM (build 1.4.2_05-b04, mixed mode)
Are you using the -server option?I was not using this option earlier but even on using this the jvm crashes after running for sometime.
I am using these jvm options now -
java -server -Xss128K -Xms256M -Xmx512M
- vineet -
Clarification of the handle/body idiom in multi threaded applications
Hello
As some DBXML classes use the handle-body idiom (handle/body idiom in some docs), could someone please clarify the consequences of that in a multi threaded application like a web container?
For 100% Java people, like me, this is known in the Java world as 'programming towards interfaces', or as the Bridge pattern; which is seen as good practice.
Let's take an example. The class XmlQueryContext is not thread safe, but it has a copy constructor. Imagine that your web application has one XmlQueryContext, that we never use in a query, but that we prepare only to be copied in new threads. Is it thus safe to instantiate various new XmlQueryContexts using that copy constructor in various new threads and use them simultaneously?
Thank you
Koen
PS What I am really asking here is if somebody could please translate the following to Java parlé:
A copy constructor is provided for this class. The class is implemented using a handle-body idiom. When a handle is copied both handles maintain a reference to the same body.As a Java user you do not have to worry about how the C++ copy constructors behave. In the Java API if a copy constructor exists for the object, then the copy constructor will copy all of the original object's data into a new object (XmlContainer is the one exception to this rule, generally one should not use that copy constructor at all). So in short, what you plan to do will work.
Lauren Foutz -
Highlight text not working in multi-thread client-server application plug-in
I'm developing a plugin application for my dissertation research on multi-application environment. I have an application server that communicate with the PDF document via plugin.
The plugin acts as both client and server, depending on the situation.
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I have a multi-threaded winsock2 IOCP running to catch client connections and when a client connected, get the data from the client (set of words), and highlight these words in the pdf document.
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I use 2 procedures, one to collect all the text from PDF and send to the server using tcp win-socket connection and another to collect data from highlight tool and send these text. both these are not threaded.
Here's my question, because I want to listen to multiple client connections, when the plugin is the server, I'm running this procedure in a thread and then wait for clients to connect and use IOCP to serve the client connections. When the client is connected I use the data coming from client to highlight some text in the PDF document. All of these functionalities are already implemented, but when I receive data from client and try to highlight text in the PDF document my application freezes up and stop working. I think this is something to do with the thread. I'm using _beginthreadex to start the server and then another _beginthreadex inside the IOCP worker thread.
I can post the code, but before that let me know if you can see any problem in this situation. What I see from other posts is that acrobat is not multi-threaded.Thanks a lot for the reply.
I guess I probably need some sort of a notification when the data is received and do a callback to the main thread to run the acrobat API. Is there anyway I can create custom notifications? Something like this,
AVAppRegisterNotification(AVDocDidOpenNSEL, gExtensionID, ASCallbackCreateNotification( AVDocDidOpen, (void *)DocIsOpenedCallback), NULL);
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The CPU utilization is 0% for the other remaining processes when multi threading is used
I am new to AE ,so I am trying to render a project enabling multi threading process the additional processes are present but their utilization is 0% .
I want to juice out every single CPU utiliaztion .
ANy help is greatly appriciated,.
My system specs:
AMD 9690 4.7 Ghz 8 core
32 GB DDR3
C:\256 GB Solid Satte Raid 0
GeForce 780 Ti DDR5 3GBIt is very tempting to try and use all of your system resources and multiprocessing for all your projects, but this is not the way After Effects works. Many third-party plug-ins, many codecs, and many operations do not respond well to multiprocessing. All it takes is one process in your entire thread that is not MP aware to foul the whole thing and give you longer render times.
You are also leaving zero processors for the rest of your computer. Not a wise idea.
After effects renders one frame at a time. One HD frame even with multiple layers of pixel processing just isn't that much data. It does take a while to do the calculations, but expecting to have every one of your CPUs jacked up at 100% to render a single frame of video is expecting an awful lot.
I would suggest that you read up on optimizing After Effects for your computer. Do not expect to be able to utilize 100% of your system resources at all times. That's just not the way processing video on a pixel by pixel basis works.
Just a little FYI, for 99% of my projects in After Effects I have render multiple frames simultaneously turned off. It just doesn't work with most of the things I do. Sorry for the disappointment. -
Java Security Manager in Multi-threaded application
I am writing a multi-threaded application listening (TCP and UDP) to several ports. To help implement certain security features (eg. refusing connections from certain ip address), I'm using the java.lang.SecurityManager (by subclassing it). I am having a few problems and queries and am hoping someone here can help me.
1. As all the threads are calling the checkAccept(host, port) method. Is there a way to know which thread is currently accessing the security manager? For example if host A were to make 2 connections to the application, one to thread 1 (say listening to port 5001) and the other to to thread 2 (say listening to port 5002). I intend to refuse the connection to thread 2 but there is not way of differentiating the 2 connections since they are from the same host and there isnt any way of knowing their port number.
2. Are calls to the Security Manager thread safe?
I have been having this problem for a long time, would appreciate if someone can help point me to the right direction. cheers.1. As all the threads are calling the
checkAccept(host, port) method. Is there a way to
know which thread is currently accessing the security
manager?Just use Thread.currentThread(). As specified in the Javadoc for e.g. SecurityManager.checkAccept().
2. Are calls to the Security Manager thread safe? No. -
Question using Java API in a multi threaded application for MDX queries
Currently I’m building a web application that makes a lot of MDX calls using the Essbase Java API. Each time we run an MDX call we basically run the following code:
IEssbase ess = IEssbase.Home.create(IEssbase.JAPI_VERSION);
IEssDomain dom = ess.signOn(userName, password, false, null, "embedded");
IEssCubeView cv = cv=dom.openCubeView("view", hostName, appName, cubeName);
IEssOpMdxQuery op = cv.createIEssOpMdxQuery();
op.setQuery(false,mdx,false,IEssOpMdxQuery.EEssMemberIdentifierType.NAME);
cv.performOperation(op);
IEssMdDataSet mddata = cv.getMdDataSet();
cv.close();
My questions is, is this the correct way to use the API in multi threaded environment where many users may be hitting the application at the same time? For every request do I need to create a separate IEssbase object and sign on to an IEssDomain? Or can I use a single IEssbase and IEssDomain object for the entire application? If not should I call the IEssDomain.signOff() method after each user’s request has completed? Which of the above objects are thread safe? I’m using Essabae 9.3.1. Any insight would be really appreciated.
Thanks
DavidThanks for the input friend,
I should have mentioned that in my application all
connections to Essbase use the same user name and
password so the filtering isn’t a concern. This is my
first Java application using Essbase has a data
source, I’m used to connecting to various SQL
databases and I always use a connection pool, how is
connection pooling handled in the Essbase java API?I'm not sure what happened to it since I never used it, but there used to be something called the High Availability Services or something that was essentially a connection pool for Essbase JAPI connections, but it required an extra license.
Since you don't care about identity (everyone has full access to everything), you can create your own connection pool, but you'll have to manage your multithreading yourself. Its been this way since the beginning. The C API isn't/wasn't thread-safe either (we tried). -
StageVideo Multi-thread for standalone player ?
Hi,
With the last version of flash player i've got a micro freeze when a HD video is decoded with StageVideo and when i make an addChild on the scene over the video.
The new version with multi-thread is supposed to resolve these problems?
From the content debugger freeze are stil there. So is the multi-thread for video playback is active for the content debugger or only for the web player version or simply not implemented yet?Remember this about threading, and I dislike the architecture here:
The run method is the code that is actually executed in-thread, but in order to run a thread - it must be started - and thus the start() method must be called.
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