Multi threaded operation

can i call system thread in labview as we do in mfc programming.

I don't think you can, but depending on your application you probably don't need to. LabVIEW is inherently multi-threaded, so it will automatically run parallel processes in separate threads if it is possible to do so.
Here is a link to an app. note which should help shed some light on the subject:
Using LabVIEW to Create Multithreaded Applications for Maximum Performance and Reliability
Hope this helps you!

Similar Messages

How should implement multi-thread in single-threaded Operating system using

How should implement multi-thread in single-threaded Operating system using java?
Java supports "Multi-threading".Is there is any way run the multiple threads (Implementing multi threading) using java in a Single-threaded Operating system (That is the operating system does not support for multi-threading).

Previous questions from OP suggest they are using J2ME, so the question might be possible.
806437 wrote:
How should implement multi-thread in single-threaded Operating system using java?
What is the actual question/problem?
A java app doesn't do threads or not do threads. It uses classes. The VM does threads.
So if you have a platform that does not have threads and you want to support the thread class then the VM, not a java app, must provide some pseudo mechanism, such as green threads, to support that.
If your question is about java code and not the VM then you must build a task engine and insure that the tasks are of short enough duration that it is an effective use for your system.

Multi-thread failure - Error in assignment

Hello
I have a c++ program processor running under Windows XP with Oracle 9i. My program access to oracle by an ODBC driver version 9.2.0.4.0. It could be launched in multi-thread to increase performance. When I launch it with one thread everything is fine. When I use several threads I have problems. ODBC driver returns to me a "error in assignment ... General error" message and my updates queries failed. Under SQl server it works without problems. It seems to be a kind of deadlock. When I disable check box in my odbc driver of "enable query timeout" my program encounter a problem and freezes...
Could someone help me ?

user13335017 wrote:
I have thought of the above solutions as workable, however, it is not. Some exhibited errors are:
A. "Attempt to use database while environment is closed." This error applies to 2, 3 and 4 all the way;
B. "Attempt to read / write database while database is closed." This error applies to 3 in particular;
C. "Attempt to close environment while some database is still open." This error applies to 5.
Please help me with designing a better strategy to solve the concurrent issue. Many thanks in advance.All these are expected errors. You should design the application so that you do not close an environment handle while database handles are still open, keep database handles open for as long as operations need to be performed on the underlying databases, open the database handles after opening the database handles, and close database handles before closing the environment handle.
In short, in pseudo-code, you should have something like this:
- open environment handle,
- open database handles,
- perform whatever operations are needed on the databases,
- close database handles,
- close environment handle.
You can refer to the Getting Started with Data Storage and the Getting Started with Transaction Processing guides appropriate for the API you are using, from the Berkeley DB documentation page.
Regards,
Andrei

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
Benoit

That 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

Connection Pooling in OCCI Vs Multi-Threading.

Hi,
I am working on an application in which I am using OCCI( Oracle C++ Call Interface) and multi-threading concepts.
My application is having different clients( Ex: Client-A, Client-B) and I am offering a set of operations( functions that trigger the Stored Procedures of DataBase ) which are common to all the clients.Each Client can send asynchronous requests of any number.So, is there any chance of using single connection( not connection pooling) to the Data Base for all the clients to manage their requests ?
Note: Multi-threaded requests are also allowed from each client.
How can I co-relate multithreading and Connection Pooling in OCCI?
Can I you multi-threading without Connection Pooling? If so how?
Will the connection pooling is needed if there is no multi threading concept in my application?
Please help me on this. Very urgent.
Thanks in Advance..:)

Connections are resources that the application uses and a fewer connections can be used by multiple threads if the threads are not always busy with the database activity only, and are doing other work too. This sharing (pooling) can be implemented by the application or the application can leverage the connection pooling features offered by OCI/OCCI (recommended).
Be aware of connections vs sessions and sharing them (refer to :
OCI Programming Advanced Topics
OCCIConnectionPool is to pool connections and OCCIStatelessConnectionPool is to pool sessions. Please see the differences in the above link and apply as appropriate.

InfoPath: the multi-threading challenge

Or to be more specific: calling a DataSource from a different thread.
A project I'm working on includes an InfoPath form in which some heavy duty tasks are executed. These tasks can take over 10+ seconds to execute. To avoid the GUI to get stuck during execution, multi-threading is implemented. The problem lies in providing
feedback to the user. Several methods have been used, but all end in the exceptions shown below.
Unlike WinForms and such, InfoPath does not seem to provide a way to invoke the GUI. What we are trying to do is change field values to reflect the status of the process. This is done through the MainDataSource. I've tried several methods to call
this datasource through another thread, like invoking a provided delegate, or execution context. However all these methods have similar results.
When calling a method or property on the datasource the following exception is thrown:
System.InvalidOperationException was unhandled
Message="Operation is not valid due to the current state of the object."
Source="Microsoft.Office.InfoPath.Client.Internal.Host"
StackTrace:
       at Microsoft.Office.Interop.InfoPath.SemiTrust.ICLRExtensionsWrapper.IncrementSqmPoint(Int32 idDataPt)
       at Microsoft.Office.InfoPath.Internal.DataSourceHost.CreateNavigator()
       at Form1.FormCode.ContextCallbackMethod(Object obj) in E:\Projects\InfoPath Multithreading\Source\Form1\FormCode.cs:line 74
       at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
       at Form1.FormCode.ThreadMethod(Object myParamsObj) in E:\Projects\InfoPath Multithreading\Source\Form1\FormCode.cs:line 68
       at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
       at System.Threading.ThreadHelper.ThreadStart(Object obj)
This seems to indicate the DataSource is locked for some reason. Even the ReadOnly property can not be read.
When calling the SetValue method on an XPathNavigator provided by a datasource and passed through another thread, the following exception is thrown:
System.AccessViolationException was unhandled
Message="Attempted to read or write protected memory. This is often an indication that other memory is corrupt."
Source="Microsoft.Office.InfoPath.Client.Internal.Host.Interop"
StackTrace:
       at Microsoft.MsoOffice.InfoPath.MsxmlInterop.NativeHelpers.SetText(IXMLDOMNode* , Char* )
       at Microsoft.MsoOffice.InfoPath.MsxmlInterop.MsxmlNodeImpl.set_Text(String strText)
       at Microsoft.Office.InfoPath.MsxmlNavigator.SetValue(String value)
       at Form1.FormCode.DelegateMethod(XPathNavigator nav) in E:\Projects\InfoPath Multithreading\Source\Form1\FormCode.cs:line 81
       at Form1.FormCode.ThreadMethod(Object myParamsObj) in E:\Projects\InfoPath Multithreading\Source\Form1\FormCode.cs:line 70
       at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
       at System.Threading.ThreadHelper.ThreadStart(Object obj)
I have searched through the internet but am unable to find any useful information about this subject. There are only a few weeks remaining before the deadline. A work-around has been implemented, but since it requires additional active user interaction
it is far from ideal. I hope you can help me in finding a solution.

For anyone who is still interested all this time later....
I wouldn't use a Dispatcher in InfoPath simply because InfoPath requires .Net 2.0 only and Dispatcher was not added until .Net 3.0 which means you would have to enforce installation of .Net 3.0 yourself.
There is an easy alternative which is SynchronizationContext (more specifically a WindowsFormsSynchronizationContext).
Also I suggest you do not use ThreadStart but rather use one of the more modern and well known threading paradigms. A good alternative is a BackgroundWorker.
e.g.
private BackgroundWorker _Worker;
public void InternalStartup()
InitializeWorker();
((ButtonEvent)EventManager.ControlEvents["Button"]).Clicked += new ClickedEventHandler(ButtonClick);
public void InitializeWorker()
_Worker = new BackgroundWorker();
_Worker.WorkerReportsProgress = true;
_Rorker.WorkerSupportsCancellation = true;
_Worker.DoWork += new DoWorkEventHandler(_Worker_DoWork);
_Worker.ProgressChanged += new ProgressChangedEventHandler(_Worker_ProgressChanged);
_Worker.RunWorkerCompleted += new RunWorkerCompletedEventHandler(_Worker_RunWorkerCompleted);
public void ButtonClick(object sender, ClickedEventArgs e)
if (_Worker.IsBusy)
_Worker.CancelAsync();
else
// Very important to include this line!
AsyncOperationManager.SynchronizationContext = new WindowsFormsSynchronizationContext();
_Worker.RunWorkerAsync();
void _Worker_DoWork(object sender, DoWorkEventArgs e)
// Do stuff in another thread and report back to the UI thread.
object state;
int percentage = 0;
_Worker.ReportProgress(percentage, state).
public void _Worker_ProgressChanged(object sender, ProgressChangedEventArgs e)
// This is called on the thread that started the worker.
// In this case the UI thread which means it is safe to use the MainDataSource.
CreateNavigator().SelectSingleNode("my:Main/my:Progress", NamespaceManager).SetValue(e.ProgressPercentage);
void _Worker_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
// Do anything you want to do on completion here.
One thing of note is that the SynchronizationContext in InfoPath for some reason or other always seems to be Null. The result is that when you call RunWorkerAsync() it captures the current synchronization context (null) which means the default is used and
a ProgressChanged is called on a new thread each time. To prevent this we need to manually set the context before calling RunWorkerAsync() which is done using the AsyncOperationManager.

Analysis for Office support multi thread?

Does Analysis for Office support multi thread/core? If so, what verison? I tried searching around this site as well as note 1466118 - Hardware & Software requirements for Analysis, edition for MS Office but was unable to find an answer.
I am on an Intel dual cpu with hyper threading turned on so it essentially looks like 4 cores. When I execute an Analysis View, I rarely see the EXCEL.EXE process go above 25% CPU utilization. I have plenty of RAM and hard drive space.
64bit Windows 7
32bit Office 2010
AAO 1.3.5.2288
Thanks

I found the following info at:
Excel 2010 Performance: Performance and Limit Improvements
Large Data Sets and 64-bit Excel
The 64-bit version of Excel 2010 is not constrained to 2 GB of RAM like 32-bit applications. Therefore, 64-bit Excel 2010 enables users to create much larger workbooks. 64-bit Windows enables a larger addressable memory capacity, and 64-bit Excel is designed to take advantage of that capacity. For example, users are able to fill more of the grid with data than was possible in previous versions of Excel. As more RAM is added to the computer, Excel uses that additional memory, allows larger and larger workbooks, and scales with the amount of RAM available.
In addition, because 64-bit Excel enables larger data sets, both 32-bit and 64-bit Excel 2010 introduce improvements to common large data set tasks such as entering and filling down data, sorting, filtering, and copying and pasting data. Memory usage is also optimized to be more efficient, in both the 32-bit and 64-bit versions of Excel.
Multi-Core Processing
Additional investments were made to take advantage of multi-core processors and increase performance for routine tasks. Starting in Excel 2010, the following features use multi-core processors: saving a file, opening a file, refreshing a PivotTable (for external data sources, except OLAP and SharePoint), sorting a cell table, sorting a PivotTable, and auto-sizing a column.
For operations that involve reading and loading or writing data, such as opening a file, saving a file or refreshing data, splitting the operation into two processes increases performance speed. The first process gets the data, and the second process loads the data into the appropriate structure in memory or writes the data to a file. In this way, as soon as the first process beings reading a portion of data, the second process can immediately start loading or writing that data, while the first process continues to read the next portion of data. Previously, the first process had to finish reading all the data in a certain section before the second process could load that section of the data into memory or write the data to a file.

Custom Popup on a Tabular Form for Multi Row Operation

I am trying to implement a custom popup on a tabular form that I can pass a value typed in to a text item like âNameâ to the popup so it can filter a list of names on what was already typed in.
Once a selection is made I need to have the selected name passed back to the text item.
This is easily done when not using a Tabular Form. Any ideas would be great?

Can someone please help me with this?
I've read the Thread:
"Custom Popup on a Tabular Form for Multi Row Operation",
and have tried following the instructions provided by Willi Firulais.
I've also tried to integrate the instructions provided by RWeide in response within the same Thread.
I cannot get the passBack function to Pass the value to the Calling Page.
(I've tried to organize the pertinent information as it pertains to my application,
and have included it here below:)
A. Calling Page (Page# 141)
1. HTML Header: (Page# 141)
<script> function callMyPopup(item) { var url;
url = 'f?p=&APP_ID.:143:&APP_SESSION.::::P143_ITEM:'+ item;
w = open(url,"winLov","Scrollbars=1,resizable=1,width=800,height=600");
if (w.opener == null) w.opener = self; w.focus(); }
</script>
2. Region Definition: (Orders) - SQL Query (Updateable Report)
a. Query:
select
'f01_'||to_char(rownum ,'FM0999') ITEM,
"ID",
"ID" ID_DISPLAY,
"ID_PROJECT",
"ID_SUPPLIER",
"DESCRIPTION",
"JOB_NO",
"QUANTITY",
"UNIT_PRICE",
"EXTENDED_PRICE",
"MANUFACTURER",
"SUPPLIER",
"PART_NO",
"GROUP_LIST",
"BILLED_PRICE",
"DATE_NEEDED",
"DATE_DELIVERED",
"SUPPLIER_TYPE",
rownum
from "#OWNER#"."OAX_MAT_ORDER_ITEMS07"
where job_no = :P141_JOB_NO
3. Report Attributes: (ITEM) - URL
javascript:callMyPopup('#ITEM#');
B. PopUp Page (Page# 143)
1. HTML Header: (Page# 143)
<script language="JavaScript"> function passBack(passItem1, passVal1)
{ opener.document.forms["wwv_flow"].SUPPLIER[&P143_ITEM.].value = passVal1;
close(); }
</script>
2. ITEMS:
P143_ITEM
3. Region Definition: (Suppliers) - SQL Query(Structured Query)
OAX_SUPPLIERS.ID
OAX_SUPPLIERS.NAME
4. Report Attributes: (NAME) - URL
javascript:passBack('&P143_ITEM.','#NAME#');
Thank you in advance for you help!

Is a Trigger Multi Thread?

I’m trying to execute a SELECT statement WHERE status = X to make some operations when I insert a row in my Table.
If there is another insert until is execute the firs insert, the Trigger is executed in other Thread or waits until the first ended?
Is a Trigger Multi Thread?
If is multi thread, is possible to make it in single thread or wait until the first one end?

Each session will execute its own copy of the trigger.
To single thread access to rows within a table look at the select for update statement.
When designing transactions give thought to Oracle's read consistency model: readers will not wait on updaters to see the row contents.
But by selecting for update you will cause other sessions that want to update the same selected row as taken by the first session to wait for the first session to commit or rollback before the second session performs its update.
If you need to single thread access to the entire table you could be designing an applciation that will not scale to support multiple session access.
HTH -- Mark D Powell --

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

Is FCE (or FCP) multi-threaded?

I'm still trying to decide on what new (probably used) computer I need and just did some reading on multi-processors. The articles I read said that, unless you need to use more than one application simultaneously, multi-processors are only of benefit if the application you are using was specifically designed to do more than one thing at a time. Yes, I use photoshop and other programs sometimes at the same time as FCE, but I don't have to. So...is FCE and/or Final Cut Pro multi-threaded to do more than one thing at the same time?
And I thank all of you who responded to my question as to whether a dual 1.8 was enough. I'm now thinking about a 2.3-2.6 dual g5.

Hello Fay,
OSX fully supports multiprocessors & multithreading. The operating system takes care of assigning tasks to the processors & managing them. Final Cut Pro is multithreaded and although I haven't definitive confirmation one way or the other I suspect Final Cut Express is also.
But the real question is are you doing video that is sufficiently demanding that you need a bigger / faster machine? There are so many factors that affect the real and apparent performance of computers, and for the vast majority of users multithreading is not the limiting factor. Processor speed, number of processors, amount of RAM, bus speed, hard drive interface & hard drive speed play a much more significant role in how fast or capable your computer is.
Will you see a difference in FCE on a single processor 1.8GHz G5 vs a dual processor 1.8GHz G5? Probably in rendering times and the number of RT effects that can be played simultaneously in the Canvas.
Will you see a difference between a 1.8GHz DP machine and a 2.3GHz DP machine? Yes, assuming they have the same amount of memory & type of hard drives. The 2.3GHz DP G5 not only has faster processors but Apple made other improvements to the G5 line over time that made them bigger / faster / better, as it does with all its product lines.
If you have the budget, believe the machine is worth the money and has a better cost/benefit ratio for you, go with the higher processor speed, but make sure you have enough RAM memory too. And don't worry about multithreading ...

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 3GB

It 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.

Multi-thread file reading

Hi,
I've got a tricky question: I have to read large files (over 150 MB) - I found here several topics about reading such a large files, but all examples were about single-threaded reading from file... Do you think, multi-threaded reading would be faster? I am in quite a dilemma: multiple threads in general means faster processing, but in this case, all threads are reading from the same source/file
(I use javax.mail.util.SharedFileInputStream for multi-threaded file reading - each stream in separated thread)
so what do you think, which is faster: single-thread or multiple-thread? and if so, how many threads would be fine - 2, 3 or 4?
thanks a lot

kvasoo wrote:
Herko_ter_Horst wrote:
The I/O thread processing thread(s) approach will work when the processing takes more time than the I/O (i.e. when the medium can transfer information faster than a single thread can process it).it is very likely that processing will take more time then file reading - there will be 5-7 regex to match per line, sometimes object creation and filling object fith some data
so it seems to be just like I wrote some posts before: while one thread is reading data from file, another could process already read data - I am just considering malcolmmc's idea of blocking queue - one thread to perform I/O operations and one thread to process data - these threads would be connected through blocking queue....hmm that sounds good to me.. thanks malcolmmc
thank you guys for your help & suggestions and if you still have something to advise me, I will be thankfulSeparation of concerns, dude. Read the raw data in, in one thread, and split out the processing to multiple threads. I really advise you take the time to actually measure the performance of the multi-threaded processing vs the single-threaded one though. I mean, really do actually do that. Don't just assume - as so many people do - that throwing more threads at every problem will always speed it up, because it's so often not the case.

Multi thread and deadlocks

I am running dataload from a text file to MS SQL SRVR database. The jobs are running in multi thread mode. I am getting deadlock errors with threads.
each thread is supposed to delete records.
with single thread mode log file order is as below
1. get product to be deleted A
2. delete A
3. get product to be deleted B
4. delete B
5. get product to be deleted C
6 delete C
with multi thread mode
1. get product to be deleted A
2. get product to be deleted B
3. get product to be deleted C
4. get product to be deleted D
5. delete A
6. get product to be deleted E
7. get product to be deleted F
8. deadlock while deleteing the product B
Any clues what is going wrong here?
Here is the code for the delete method:
================================
PreparedStatement prepStatement = null;
System.out.println("get product to be deleted " + product);
prepStatement = conn.prepareStatement("delete from MYTABLE where product = ? ");
prepStatement.setString(1, product);
prepStatement.executeUpdate();
================================
Please note that only unique data is sent to each thread.
Any help is greatly appreciated.
Thanks

Thanks for the responses. I need to do update/insert new records after delete operation is completed. Later at the end of the db changes, i close the connection.
From my understanding deadlocks happen when both threads try to touch the same record same time. But, i am sending unique records for each thread. Unless these is somethign wrong with the query, it should always return unique values.
This is the query that sends unique records for each thread in sql srvr.
select distinct top ? columnA, columnB from MyTable where processed = 'FALSE' and columnB = ? "
This should be equivalent of oracle query
select distinct columnA, columnB from MyTable where columnB=? rownum > ? and rownum <= ?
if the top in sql srvr is equivalent to rownum in oracle then i always get distinct records and there should be no deadlocks.
Any help?
Thanks

Multi-threaded program hangs in Linux with green thread when doing I/O

Hi,
I am using green thread(jdk1.3.1) on Linux. My program is in multi-threaded model and has some I/O operations. I am runing one java program using Runtime.exec("java <program>"). Actually the <program> prompts user with some question like "enter location" and waits for the input. Now in my code I am constantly reading the input stream of the process. Once I get the string like "enter location", immediately I send the location through Process o/p stream. But the process is not able to read this and hangs there for ever.
Please help, what could be the problem? If you need the source code, pls let me know.
Thanks in advance,
Sisir

I had a similar issue few weeks back... If I could see the source I would have a better understanding of the problem and think I could help out. If you want to send it, send it to [email protected]
thanks,
JP

Multi threaded operation

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