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• Getting a key in the ActionScript Dictionary

  - by Rudy

  Hello, I am using a Dictionary in ActionScript as a queue, sort of, still reading most of the time as an associative container, but I need one time to make a loop to run through the whole dictionary, such as for (var key:String in queue) . Inside this for loop I perform some actions on an element and then call delete on that key. My issue is that I would like to wait for an Event before fetching the next element in this queue. Basically my for loop runs too fast. I would like to fetch the next key all the time, but I know there is no built in method. A solution I thought is to add a break to the loop, as the for.. in will automatically fetch the next key, but it would be a loop which always executes one time, simply to fetch the next key. This sounds a bit counter intuitive. I hope my problem makes sense and I really look for some better ideas than what I currently have. Thanks for your help! Rudy

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• Can I use POSIX signals in my Perl program to create event-driven programming?

  - by Shiftbit

  Is there any POSIX signals that I could utilize in my Perl program to create event-driven programming? Currently, I have multi-process program that is able to cross communicate but my parent thread is only able to listen to listen at one child at a time. foreach (@proc) { sysread(${$_}{'read'}, my $line, 100); #problem here chomp($line); print "Parent hears: $line\n"; } The problem is that the parent sits in a continual wait state until it receives it a signal from the first child before it can continue on. I am relying on 'pipe' for my intercommunication. My current solution is very similar to: http://stackoverflow.com/questions/2558098/how-can-i-use-pipe-to-facilitate-interprocess-communication-in-perl If possible I would like to rely on a $SIG{...} event or any non-CPAN solution. Update: As Jonathan Leffler mentioned, kill can be used to send a signal: kill USR1 = $$; # send myself a SIGUSR1 My solution will be to send a USR1 signal to my child process. This event tells the parent to listen to the particular child. child: kill USR1 => $parentPID if($customEvent); syswrite($parentPipe, $msg, $buffer); #select $parentPipe; print $parentPipe $msg; parent: $SIG{USR1} = { #get child pid? sysread($array[$pid]{'childPipe'}, $msg, $buffer); }; But how do I get my the source/child pid that signaled the parent? Have the child Identify itself in its message. What happens if two children signal USR1 at the same time?

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• Distributed Message Ordering

  - by sbanwart

  I have an architectural question on handling message ordering. For purposes of this question, the transport is irrelevant, so I'm not going to specify one. Say we have three systems, a website, a CRM and an ERP. For this example, the ERP will be the "master" system in terms of data ownership. The website and the CRM can both send a new customer message to the ERP system. The ERP system then adds a customer and publishes the customer with the newly assigned account number so that the website and CRM can add the account number to their local customer records. This is a pretty straight forward process. Next we move on to placing orders. The account number is required in order for the CRM or website to place an order with the ERP system. However the CRM will permit the user to place an order even if the customer lacks an account number. (For this example assume we can't modify the CRM behavior) This creates the possibility that a user could create a new customer, and place an order before the account number gets updated in the CRM. What is the best way to handle this scenario? Would it be best to send the order message sans account number and let it go to an error queue? Would it be better to have the CRM endpoint hold the message and wait until the account number is updated in the CRM? Maybe something completely different that I haven't thought of? Thanks in advance for any help.

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• does lucene search function work in large size document?

  - by shaon-fan

  Hi,there I have a problem when do search with lucene. First, in lucene indexing function, it works well to huge size document. such as .pst file, the outlook mail storage. It can build indexing file include all the information of .pst. The only problem is to large sometimes, include very much words. So when i search using lucene, it only can process the front part of this indexing file, if one word come out the back part of the indexing file, it couldn't find this word and no hits in result. But when i separate this indexing file to several parts in stupid way when debugging, and searching every parts, it can work well. So i want to know how to separate indexing file, how much size should be the limit of searching? cheers and wait 4 reply. ++++++++++++++++++++++++++++++++++++++++++++++++++ hi,there, follow Coady siad, i set the length to max 2^31-1. But the search result still can't include what i want. simply, i convert the doc word to string array[] to analyze, one doc word has 79680 words include the space and any symbol. when i search certain word, it just return 300 count, actually it has more than 300 results. The same reason, when i search a word in back part of the doc, it also couldn't find. //////////////set the length idexwriter.SetMaxFieldLength(2147483647); ////////////////////search IndexSearcher searcher = new ndexSearcher(Program.Parameters["INDEX_LOCATION"].ToString()); Hits hits = searcher.Search(query); This is my code, as others same. I found that problem when i need to count every word hits in a doc. So i also found it couldn't search word in back part of doc. pls help me to find, is there any set searcher length somewhere? how u meet this problem.

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• What are the options for overriding Django's cascading delete behaviour?

  - by Tom

  Django models generally handle the ON DELETE CASCADE behaviour quite adequately (in a way that works on databases that don't support it natively.) However, I'm struggling to discover what is the best way to override this behaviour where it is not appropriate, in the following scenarios for example: ON DELETE RESTRICT (i.e. prevent deleting an object if it has child records) ON DELETE SET NULL (i.e. don't delete a child record, but set it's parent key to NULL instead to break the relationship) Update other related data when a record is deleted (e.g. deleting an uploaded image file) The following are the potential ways to achieve these that I am aware of: Override the model's delete() method. While this sort of works, it is sidestepped when the records are deleted via a QuerySet. Also, every model's delete() must be overridden to make sure Django's code is never called and super() can't be called as it may use a QuerySet to delete child objects. Use signals. This seems to be ideal as they are called when directly deleting the model or deleting via a QuerySet. However, there is no possibility to prevent a child object from being deleted so it is not usable to implement ON CASCADE RESTRICT or SET NULL. Use a database engine that handles this properly (what does Django do in this case?) Wait until Django supports it (and live with bugs until then...) It seems like the first option is the only viable one, but it's ugly, throws the baby out with the bath water, and risks missing something when a new model/relation is added. Am I missing something? Any recommendations?

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• How can I use `pipe` to facilitate interprocess communication in Perl?

  - by Shiftbit

  Can anyone explain how I can successfully get my processes communicating? I find the perldoc on IPC confusing. What I have so far is: $| = 1; $SIG{CHLD} = {wait}; my $parentPid = $$; if ($pid = fork();) ) { if ($pid == 0) { pipe($parentPid, $$); open PARENT, "<$parentPid"; while (<PARENT>) { print $_; } close PARENT; exit(); } else { pipe($parentPid, $pid); open CHILD, ">$pid"; or error("\nError opening: childPid\nRef: $!\n"); open (FH, "<list") or error("\nError opening: list\nRef: $!\n"); while(<FH>) { print CHILD, $_; } close FH or error("\nError closing: list\nRef: $!\n"); close CHILD or error("\nError closing: childPid\nRef: $!\n); } else { error("\nError forking\nRef: $!\n"); } First: What does perldoc pipe mean by READHANDLE, WRITEHANDLE? Second: Can I implement a solution without relying on CPAN or other modules?

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• How to correctly waitFor() a saveScreenShot() end of execution.

  - by Alain

  Here is my full first working test: var expect = require('chai').expect; var assert = require('assert'); var webdriverjs = require('webdriverjs'); var client = {}; var webdriverOptions = { desiredCapabilities: { browserName: 'phantomjs' }, logLevel: 'verbose' }; describe('Test mysite', function(){ before(function() { client = webdriverjs.remote( webdriverOptions ); client.init(); }); var selector = "#mybodybody"; it('should see the correct title', function(done) { client.url('http://localhost/mysite/') .getTitle( function(err, title){ expect(err).to.be.null; assert.strictEqual(title, 'My title page' ); }) .waitFor( selector, 2000, function(){ client.saveScreenshot( "./ExtractScreen.png" ); }) .waitFor( selector, 7000, function(){ }) .call(done); }); after(function(done) { client.end(done); }); }); Ok, it does not do much, but after working many hours to get the environement correctly setup, it passed. Now, the only way I got it working is by playing with the waitFor() method and adjust the delays. It works, but I still do not understand how to surely wait for a png file to be saved on disk. As I will deal with tests orders, I will eventually get hung up from the test script before securely save the file. Now, How can I improve this screen save sequence and avoid loosing my screenshot ? Thanks.

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• emacs: Inferior-mode python-shell appears "lagged"

  - by Begbie00

  Hi all - I'm a Python(3.1.2)/emacs(23.2) newbie teaching myself tkinter using the pythonware tutorial found here. Relevant code is pasted below the question. Question: when I click the Hello button (which should call the say_hi function) why does the inferior python shell (i.e. the one I kicked off with C-c C-c) wait to execute the say_hi print function until I either a) click the Quit button or b) close the root widget down? When I try the same in IDLE, each click of the Hello button produces an immediate print in the IDLE python shell, even before I click Quit or close the root widget. Is there some quirk in the way emacs runs the Python shell (vs. IDLE) that causes this "lagged" behavior? I've noticed similar emacs lags vs. IDLE as I've worked through Project Euler problems, but this is the clearest example I've seen yet. FYI: I use python.el and have a relatively clean init.el... (setq python-python-command "d:/bin/python31/python") is the only line in my init.el. Thanks, Mike === Begin Code=== from tkinter import * class App: def __init__(self,master): frame = Frame(master) frame.pack() self.button = Button(frame, text="QUIT", fg="red", command=frame.quit) self.button.pack(side=LEFT) self.hi_there = Button(frame, text="Hello", command=self.say_hi) self.hi_there.pack(side=LEFT) def say_hi(self): print("hi there, everyone!") root = Tk() app = App(root) root.mainloop()

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• facebook javascript api

  - by ngreenwood6

  I am trying to get my status from facebook using the javascript api. I have the following code: <div id="fb-root"></div> <div id="data"></div> <script src="http://connect.facebook.net/en_US/all.js"></script> <script type="text/javascript"> (function(){ FB.init({ appId : 'SOME ID', status : true, // check login status cookie : true, // enable cookies to allow the server to access the session xfbml : true // parse XFBML }); }); getData(); function getData(){ var query = FB.Data.query('SELECT message FROM status WHERE uid=12345 LIMIT 10'); query.wait(function(rows) { for(i=0;i<rows.length;i++){ document.getElementById('data').innerHTML += 'Your status is ' + rows[i].message + '<br />'; } }); } </script> When i try to get my name it works fine but the status is not working. Can someone please tell me what I am doing wrong because the documentation for this is horrible. And yes I replaced the uid with a fake one and yes i put in my app id because like i said when i try to get my name it works fine. Any help is appreciated.

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• ConcurrentLinkedQueue$Node remains in heap after remove()

  - by action8

  I have a multithreaded app writing and reading a ConcurrentLinkedQueue, which is conceptually used to back entries in a list/table. I originally used a ConcurrentHashMap for this, which worked well. A new requirement required tracking the order entries came in, so they could be removed in oldest first order, depending on some conditions. ConcurrentLinkedQueue appeared to be a good choice, and functionally it works well. A configurable amount of entries are held in memory, and when a new entry is offered when the limit is reached, the queue is searched in oldest-first order for one that can be removed. Certain entries are not to be removed by the system and wait for client interaction. What appears to be happening is I have an entry at the front of the queue that occurred, say 100K entries ago. The queue appears to have the limited number of configured entries (size() == 100), but when profiling, I found that there were ~100K ConcurrentLinkedQueue$Node objects in memory. This appears to be by design, just glancing at the source for ConcurrentLinkedQueue, a remove merely removes the reference to the object being stored but leaves the linked list in place for iteration. Finally my question: Is there a "better" lazy way to handle a collection of this nature? I love the speed of the ConcurrentLinkedQueue, I just cant afford the unbounded leak that appears to be possible in this case. If not, it seems like I'd have to create a second structure to track order and may have the same issues, plus a synchronization concern.

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• pthread condition variables on Linux, odd behaviour.

  - by janesconference

  Hi. I'm synchronizing reader and writer processes on Linux. I have 0 or more process (the readers) that need to sleep until they are woken up, read a resource, go back to sleep and so on. Please note I don't know how many reader processes are up at any moment. I have one process (the writer) that writes on a resource, wakes up the readers and does its business until another resource is ready (in detail, I developed a no starve reader-writers solution, but that's not important). To implement the sleep / wake up mechanism I use a Posix condition value, pthread_cond_t. The clients call a pthread_cond_wait() on the variable to sleep, while the server does a pthread_cond_broadcast() to wake them all up. As the manual says, I surround these two calls with a lock/unlock of the associated pthread mutex. The condition variable and the mutex are initialized in the server and shared between processes through a shared memory area (because I'm not working with threads, but with separate processes) an I'm sure my kernel / syscall support it (because I checked _POSIX_THREAD_PROCESS_SHARED). What happens is that the first client process sleeps and wakes up perfectly. When I start the second process, it blocks on its pthread_cond_wait() and never wakes up, even if I'm sure (by the logs) that pthread_cond_broadcast() is called. If I kill the first process, and launch another one, it works perfectly. In other words, the condition variable pthread_cond_broadcast() seems to wake up only one process a time. If more than one process wait on the very same shared condition variable, only the first one manages to wake up correctly, while the others just seem to ignore the broadcast. Why this behaviour? If I send a pthread_cond_broadcast(), every waiting process should wake up, not just one (and, however, not always the same one).

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• Is ADO.NET Entity framework database schema update possible ?

  - by fyasar

  Hi All I'm working on proof of concept application like crm and i need your some advice. My application's data layer completely dynamic and run onto EF 3.5. When the user update the entity, change relation or add new column to the database, first i'm planning make for these with custom classes. After I rebuild my database model layer with new changes during the application runtime. And my model layer tie with tightly coupled to my project for easy reflecting model layer changes (It connected to my project via interfaces and loading onto to application domain in the runtime). I need to create dynamic entities, create entity relations and modify them during the runtime after that i need to create change database script for updating database schema. I know ADO.NET team says "we will be able to provide this property in EF 4.0", but i don't need to wait for them. How can i update database changes during the runtime via EF 3.5 ? For example, i need to create new entity or need to change some entity schema, add new properties or change property types after than how can apply these changes on the physical database schema ? Any ideas ?

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• Best strategy for synching data in iPhone app

  - by iamj4de

  I am working on a regular iPhone app which pulls data from a server (XML, JSON, etc...), and I'm wondering what is the best way to implement synching data. Criteria are speed (less network data exchange), robustness (data recovery in case update fails), offline access and flexibility (adaptable when the structure of the database changes slightly, like a new column). I know it varies from app to app, but can you guys share some of your strategy/experience? For me, I'm thinking of something like this: 1) Store Last Modified Date in iPhone 2) Upon launching, send a message like getNewData.php?lastModifiedDate=... 3) Server will process and send back only modified data from last time. 4) This data is formatted as so: <+><data id="..."></data></+> // add this to SQLite/CoreData <-><data id="..."></data></-> // remove this <%><data id="..."><attribute>newValue</attribute></data></%> // new modified value I don't want to make <+, <-, <%... for each attribute as well, because it would be too complicated, so probably when receive a <% field, I would just remove the data with the specified id and then add it again (assuming id here is not some automatically auto-incremented field). 5) Once everything is downloaded and updated, I will update the Last Modified Date field. The main problem with this strategy is: If the network goes down when I am updating something = the Last Modified Date is not yet updated = next time I relaunch the app, I will have to go through the same thing again. Not to mention potential inconsistent data. If I use a temporary table for update and make the whole thing atomic, it would work, but then again, if the update is too long (lots of data change), the user has to wait a long time until new data is available. Should I use Last-Modified-Date for each of the data field and update data gradually?

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• help('modules') crashing?

  - by Chris

  I was trying to install a module for opencv and added an opencv.pth file to the folder beyond my sites.py file. I have since deleted it and no change. When I try to run help('modules'), I get the following error: Please wait a moment while I gather a list of all available modules... /System/Library/Frameworks/Python.framework/Versions/2.5/Extras/lib/python/twisted/words/im/init.py:8: UserWarning: twisted.im will be undergoing a rewrite at some point in the future. warnings.warn("twisted.im will be undergoing a rewrite at some point in the future.") /System/Library/Frameworks/Python.framework/Versions/2.5/lib/python2.5/pkgutil.py:110: DeprecationWarning: The wxPython compatibility package is no longer automatically generated or actively maintained. Please switch to the wx package as soon as possible. import(name) Traceback (most recent call last): File "", line 1, in File "/System/Library/Frameworks/Python.framework/Versions/2.5/lib/python2.5/site.py", line 348, in call return pydoc.help(*args, **kwds) File "/System/Library/Frameworks/Python.framework/Versions/2.5/lib/python2.5/pydoc.py", line 1644, in call self.help(request) File "/System/Library/Frameworks/Python.framework/Versions/2.5/lib/python2.5/pydoc.py", line 1681, in help elif request == 'modules': self.listmodules() File "/System/Library/Frameworks/Python.framework/Versions/2.5/lib/python2.5/pydoc.py", line 1802, in listmodules ModuleScanner().run(callback) File "/System/Library/Frameworks/Python.framework/Versions/2.5/lib/python2.5/pydoc.py", line 1853, in run for importer, modname, ispkg in pkgutil.walk_packages(): File "/System/Library/Frameworks/Python.framework/Versions/2.5/lib/python2.5/pkgutil.py", line 110, in walk_packages import(name) File "/BinaryCache/wxWidgets/wxWidgets-11~262/Root/System/Library/Frameworks/Python.framework/Versions/2.5/Extras/lib/python/wxaddons/init.py", line 180, in import_hook File "/Library/Python/2.5/site-packages/ctypes_opencv/init.py", line 19, in from ctypes_opencv.cv import * File "/BinaryCache/wxWidgets/wxWidgets-11~262/Root/System/Library/Frameworks/Python.framework/Versions/2.5/Extras/lib/python/wxaddons/init.py", line 180, in import_hook File "/Library/Python/2.5/site-packages/ctypes_opencv/cv.py", line 2567, in ('desc', CvMat_r, 1), # CvMat* desc File "/Library/Python/2.5/site-packages/ctypes_opencv/cxcore.py", line 114, in cfunc return CFUNCTYPE(result, *atypes)((name, dll), tuple(aflags)) AttributeError: dlsym(0x2674d10, cvCreateFeatureTree): symbol not found What gives?!

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• Shell script task status monitoring

  - by Bikram Agarwal

  I'm running an ANT task in background and checking in 60 second intervals whether that task is complete or not. If it is not, every 60 seconds, a message should be displayed on screen - "Deploy process is still running. $slept seconds since deploy started", where $slept is 60, 120, 180 n so on. There's a limit of 1200 seconds, after which the script will show the log via 'ant log' command and ask the user whether to continue. If the user chooses to continue, 300 seconds are added to the time limit and the process repeats. The code that I am using for this task is - ant deploy & limit=1200 deploy_check() { while [ ${slept:-0} -le $limit ]; do sleep 60 && slept=`expr ${slept:-0} + 60` if [ $$ = "`ps -o ppid= -p $!`" ]; then echo "Deploy process is still running. $slept seconds since deploy started." else wait $! && echo "Application ${New_App_Name} deployed successfully" || echo "Deployment of ${New_App_Name} failed" break fi done } deploy_check if [ $$ = "`ps -o ppid= -p $!`" ]; then echo "Deploy process did not finish in $slept seconds. Here's the log." ant log echo "Do you want to kill the process? Press Ctrl+C to kill. Press Enter to continue." read log limit=`expr ${limit} + 300` deploy_check fi Now, the problem is - this code is not working. This looks like a perfectly good code and yet, this is not working. Can anyone point out what is wrong with this code, please.

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• Communication between parent and child

  - by Pierre

  Hi every one ! I have a little problem. I have to code a simple C application that creat a process and his child (fork()) and I have to do an operation. Parent initialize the values and child calculate. I write this : #include #include #include #include #include typedef struct { int op1; char op; int op2; }Operation; Operation *varOP; void finalResult() { float result = 0; if(varOP-op == '+') result = (varOP-op1 + varOP-op2); if(varOP-op == '-') result = (varOP-op1 - varOP-op2); if(varOP-op == '*') result = (varOP-op1 * varOP-op2); if(varOP-op == '+') result = (varOP-op1 / varOP-op2); printf("%f",result); } int main () { int p; varOP = (Operation *)malloc(sizeof(Operation)); p = fork(); if(p == 0) // If child { signal(SIGUSR1, finalResult ); pause(); } if(p 0) // If parent { varOP-op = '+'; varOP-op1 = 2; varOP-op2 = 3; kill(p, SIGUSR1); wait(NULL); } return 0; } But my child is never called. Is there something wrong with my code? Thanks for your help !

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• ASP.NET retrieve Average CPU Usage

  - by Sam

  Last night I did a load test on a site. I found that one of my shared caches is a bottleneck. I'm using a ReaderWriterLockSlim to control the updates of the data. Unfortunately at one point there are ~200 requests trying to update the data at approximately the same time. This also coincided with CPU usage spikes. The data being updated is in the ASP.NET Cache. What I'd like to do is if the CPU usage is around 75%, I'd like to just skip the cache and hit the database on another machine. My problem is that I don't know how expensive it is to create a new performance counter to check the cpu usage. Also, if I would probably like the average cpu usage over the last 2 or 3 seconds. However, I can't sit there and calculate the cpu time as that would take longer than it's taking to update the cache currently. Is there an easy way to get the average CPU usage? Are there any drawbacks to this? I'm also considering totaling the wait count for the lock and then at a certain threshold switch over to the database. The concern I had with this approach would be that changing hardware might allow more locks with less of a strain on the system. And also finding the right balance for the threshold would be cumbersome and it doesn't take into account any other load on the machine. But it's a simple approach, and simple is 99% of the time better.

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• How to make Web Storage persistent in Cordova using JS?

  - by ett

  I have a small quiz app, which is a cross-platform mobile app, that I plan for it to run on Android, iOS, and WP8. I want to store a local highscore, where it will keep track how many points the user had, and if he/she does better than the already stored highscore, update the current highscore. Though, I want the highscore to be persistent, what I mean is, every time the user opens the app I want the last highscore to be present and it to be compared with the new quiz score. Meaning, I don't want the highscore to be deleted after each time the app is closed. I also want for the first time when the app is ran, the highscore to be set to 0, so obviously the first time the user finishes the quiz gets a new highscore. I have those codes so far: scoredb.js // Wait for device API libraries to load document.addEventListener("deviceready", initScoreDB, false); // Device APIs are available function initScoreDB() { window.localStorage.setItem("score", 0); highscore = window.localStorage.getItem("score"); } main.js var correct = 0; var highscore; // In between I have some code that keeps incrementing // correct variable for each correct answer. if (correct > highscore) { window.localStorage.setItem("score", correct); highscore = correct; } It does seem to work okay once the app is started. I did the quiz three times, in the simulator, and it keeps the score as it should. Though, each time I open the app, highscore is reseted to 0. I guess it is due to the fact that I call initScoreDB when the device is ready, and I initialize the score to 0 there and give that value to highscore. Can someone help me to initialize the score to 0 only when the app is ran for the first time, and all the other times to keep the latest highscore as the current highscore and compare it each time with the score that is achieved when the quiz is finished. If someone can help me, I would be glad.

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• Long running transactions with Spring and Hibernate?

  - by jimbokun

  The underlying problem I want to solve is running a task that generates several temporary tables in MySQL, which need to stay around long enough to fetch results from Java after they are created. Because of the size of the data involved, the task must be completed in batches. Each batch is a call to a stored procedure called through JDBC. The entire process can take half an hour or more for a large data set. To ensure access to the temporary tables, I run the entire task, start to finish, in a single Spring transaction with a TransactionCallbackWithoutResult. Otherwise, I could get a different connection that does not have access to the temporary tables (this would happen occasionally before I wrapped everything in a transaction). This worked fine in my development environment. However, in production I got the following exception: java.sql.SQLException: Lock wait timeout exceeded; try restarting transaction This happened when a different task tried to access some of the same tables during the execution of my long running transaction. What confuses me is that the long running transaction only inserts or updates into temporary tables. All access to non-temporary tables are selects only. From what documentation I can find, the default Spring transaction isolation level should not cause MySQL to block in this case. So my first question, is this the right approach? Can I ensure that I repeatedly get the same connection through a Hibernate template without a long running transaction? If the long running transaction approach is the correct one, what should I check in terms of isolation levels? Is my understanding correct that the default isolation level in Spring/MySQL transactions should not lock tables that are only accessed through selects? What can I do to debug which tables are causing the conflict, and prevent those tables from being locked by the transaction?

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• Parallel version of loop not faster than serial version

  - by Il-Bhima

  I'm writing a program in C++ to perform a simulation of particular system. For each timestep, the biggest part of the execution is taking up by a single loop. Fortunately this is embarassingly parallel, so I decided to use Boost Threads to parallelize it (I'm running on a 2 core machine). I would expect at speedup close to 2 times the serial version, since there is no locking. However I am finding that there is no speedup at all. I implemented the parallel version of the loop as follows: Wake up the two threads (they are blocked on a barrier). Each thread then performs the following: Atomically fetch and increment a global counter. Retrieve the particle with that index. Perform the computation on that particle, storing the result in a separate array Wait on a job finished barrier The main thread waits on the job finished barrier. I used this approach since it should provide good load balancing (since each computation may take differing amounts of time). I am really curious as to what could possibly cause this slowdown. I always read that atomic variables are fast, but now I'm starting to wonder whether they have their performance costs. If anybody has some ideas what to look for or any hints I would really appreciate it. I've been bashing my head on it for a week, and profiling has not revealed much.

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• Replace low level web-service reference call transport with custom one

  - by hoodoos

  I'm not sure if title sounds right actually, so I will give more explanation here. I will begin from very beginning :) I'm using c# and .net for my development. I have an application that makes requests to some soap web-service and for each user request it produces 3 to 10 requests for web-service, they should all run async to finish in one time, so I use Async method of the web-service generated reference and then wait for result on callback. But it seems like it starts a thread (or takes it from pool) for every async call I make, so if I have 10 clients I got to spawn 30 to 100 threads and it sounds terrible even for my 16 cores server :) So i wanted to replace low level transport implementation with my own which uses non-blocking sockets and can handle at least 50 sockets run parallel in one thread with not much overhead. But I actually dunno where to put my override best. I analyzed System.Web.Services.Protocols.SoapHttpClientProtocol class and see that it has some GetWebRequest method which I actually could use. If only I could somehow interupt the object it creates and get a http request with all headers and body from there and then send it with my own sockets.. Any ideas what approach to use? Or maybe there's something built in the framework I can use?

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• [php] Cookies only changing value every two page refreshes?

  - by Gazillion

  Hello, I'm trying to implement some pixel tracking where I will save certain values in a cookie to then forward users to another page. If users purchase a product after being forwarded to the online store by us the store adds an image tag in the page with our php script included. With the values set in the cookie we would like to track conversions. I understand this tracking technique has some limitations (like if a user has cookies turned off or if they do not load images but that's the direction my client wanted to go in). The problem I'm having is that the cookie's behaviour is extremely... random. I've been trying to track their values (with a var_dump so I don't have to wait for a page reload to view the cookie's value) but it seems the value for one field only gets refreshed every two page reloads. setcookie("tracking[cn]", $cn, time()+3600*24*7,'/','mydomain.com'); setcookie("tracking[t]", $t, time()+3600*24*7,'/','mydomain.com'); setcookie("tracking[kid]", $kid, time()+3600*24*7,'/','mydomain.com'); redirectTo($redirect_url); the values of cn, t are fine but for some reason kid is always wrong (having taken the value of the previous kid) Any help would be extremely appreciated I've been at this all evening! :)

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• hibernate c3p0 broken pipe

  - by raven_arkadon

  Hi, I'm using hibernate 3 with c3p0 for a program which constantly extracts data from some source and writes it to a database. Now the problem is, that the database might become unavailable for some reasons (in the simplest case: i simply shut it down). If anything is about to be written to the database there should not be any exception - the query should wait for all eternity until the database becomes available again. If I'm not mistaken this is one of the things the connection pool could do for me: if there is a problem with the db, just retry to connect - in the worst case for infinity. But instead i get a broken pipe exception, sometimes followed by connection refused and then the exception is passed to my own code, which shouldn't happen. Even if I catch the exception, how could i cleanly reinitialize hibernate again? (So far without c3p0 i simply built the session factory again, but i wouldn't be surprised if that could leak connections (or is it ok to do so?)). The database is Virtuoso open source edition. My hibernate.xml.cfg c3p0 config: <property name="hibernate.connection.provider_class">org.hibernate.connection.C3P0ConnectionProvider</property> <property name="hibernate.c3p0.breakAfterAcquireFailure">false</property> <property name="hibernate.c3p0.acquireRetryAttempts">-1</property> <property name="hibernate.c3p0.acquireRetryDelay">30000</property> <property name="hibernate.c3p0.automaticTestTable">my_test_table</property> <property name="hibernate.c3p0.initialPoolSize">3</property> <property name="hibernate.c3p0.minPoolSize">3</property> <property name="hibernate.c3p0.maxPoolSize">10</property> btw: The test table is created and i get tons of debug output- so it seems it actually reads the config.

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• Advanced All In One .NET Framework

  - by alfredo dobrekk

  Hi, i m starting a new project that would basically take input from user and save them to database among about 30 screens, and i would like to find a framework that will allow the maximum number of these features out of the box : .net c#. windows form. unit testing continuous integration screens with lists, combo boxes, text boxes, add, delete, save, cancel that are easy to update when you add a property to your classes or a field to your database. auto completion on controls to help user find its way use of an orm like nhibernate easy multithreading and display of wait screens for user easy undo redo tabbed child windows search forms ability to grant access to some functionnalities according to user profiles mvp/mvvm or whatever design patterns either some code generation from database to c# classe or generation of database schema from c# classes some kind of database versioning / upgrade to easily update database when i release patches to application once in production automatic control resizing code metrics analysis some code generator i can use against my entities that would generate some rough form i can rearrange after code documentation generator ... Any ideas ? I know its lot but i really would like to use existing code to build upon so i can focus on business rules. Could splitting the requirements on 3 or 4 existing open source framework be possible ? Do u have any suggestion to add to the list before starting ? What open source tools would u use to achieve these ?

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• 1k of Program Space, 64 bytes of RAM. Is 1 wire communication possible?

  - by Earlz

  (If your lazy see bottom for TL;DR) Hello, I am planning to build a new (prototype) project dealing with physical computing. Basically, I have wires. These wires all need to have their voltage read at the same time. More than a few hundred microseconds difference between the readings of each wire will completely screw it up. The Arduino takes about 114 microseconds. So the most I could read is 2 or 3 wires before the latency would skew the accuracy of the readings. So my plan is to have an Arduino as the "master" of an array of ATTinys. The arduino is pretty cramped for space, but it's a massive playground compared to the tinys. An ATTiny13A has 1k of flash ROM(program space), 64 bytes of RAM, and 64 bytes of (not-durable and slow) EEPROM. (I'm choosing this for price as well as size) The ATTinys in my system will not do much. Basically, all they will do is wait for a signal from the Master, and then read the voltage of 1 or 2 wires and store it in RAM(or possibly EEPROM if it's that cramped). And then send it to the Master using only 1 wire for data.(no room for more than that!). So far then, all I should have to do is implement trivial voltage reading code (using built in ADC). But this communication bit I'm worried about. Do you think a communication protocol(using just 1 wire!) could even be implemented in such constraints? TL;DR: In less than 1k of program space and 64 bytes of RAM(and 64 bytes of EEPROM) do you think it is possible to implement a 1 wire communication protocol? Would I need to drop to assembly to make it fit? I know that currently my Arduino programs linking to the Wiring library are over 8k, so I'm a bit concerned.

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