Search Results

Search found 16237 results on 650 pages for 'lock free'.

Page 282/650 | < Previous Page | 278 279 280 281 282 283 284 285 286 287 288 289  | Next Page >

  • Cocoa multhithreads, locks don't work

    - by Igor
    I have a threadMethod which shows in console robotMotorsStatus every 0.5 sec. But when I try to change robotMotorsStatus in changeRobotStatus method I receive an exception. Where I need to put locks in that program. #import "AppController.h" @implementation AppController extern char *robotMotorsStatus; - (IBAction)runThread:(id)sender { [self performSelectorInBackground:@selector(threadMethod) withObject:nil]; } - (void)threadMethod { char string_to_send[]="QFF001100\r"; //String prepared to the port sending (first inintialization) string_to_send[7] = robotMotorsStatus[0]; string_to_send[8] = robotMotorsStatus[1]; while(1){ [theLock lock]; usleep(500000); NSLog (@"Robot status %s", robotMotorsStatus); [theLock unlock]; } } - (IBAction)changeRobotStatus:(id)sender { robotMotorsStatus[0]='1'; }

    Read the article

  • Threading Problems in ActionScript 2.0?

    - by yar
    Is it possible to have concurrency problems (thread competition) in an onEnterFrame method in ActionScript 2.0? I have written this cheesy code as a guard: if (!busy) { // I suspect some threading problems: is that even possible in flash busy = true; movePanels(); busy = false; } but this is no assurance against thread competition. If so, how can I do a basic semaphore/lock? Note: I suspect threading problems in my app, but if they're impossible, I'll check my code differently.

    Read the article

  • Mysql Master Slave Replication on Large Database table (how to sync initial data)

    - by Brian Lovett
    We have a production server and a dev server. We have found that backups are nearly impossible on the production server because of the query volume we experience. So, we're looking at setting up replication with our dev server being the slave. This is ideal because we can afford to lock the tables on that server and additionally it will be nice to have up to date data for the developers. Now, the issues. The production server can't really be taken down or locked at this point, at least not easily. We have a high query volume and fairly large 30+ GB innodb tables. Both servers are running all innodb and are also both on mysql 5.1. What can we do to sync the data initially to get replication started? I've tried a few options, but so far, none have worked.

    Read the article

  • DispatcherOperations.Wait()

    - by Mark
    What happens if you call dispatcherOperation.Wait() on an operation that has already completed? Also, the docs say that it returns a DispatcherOperationStatus, but wouldn't that always be Completed since it (supposedly) doesn't return until it's done? I was trying to use it like this: private void Update() { while (ops.Count > 0) ops.Dequeue().Wait(); } public void Add(T item) { lock (sync) { if (dispatcher.CheckAccess()) { list.Add(item); OnCollectionChanged(new NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction.Add, item)); } else { ops.Enqueue(dispatcher.BeginInvoke(new Action<T>(Add), item)); } } } I'm using this in WPF, so all the Add operations have to occur on the UI thread, but I figured I could basically just queue them up without having to wait for it to switch threads, and then just call Update() before any read operations to ensure that the list is up to date, but my program started hanging.

    Read the article

  • display the item in tdbmemo from combobox

    - by zizil
    i have combobox that have value category1 and category2...the category1 have items like pencil,food,magazine,newspaper... when i choose category1, i want to retrieve the items in tdbmemo.then the same items in tdbmemo i want to display in checklistbox...i dont know how to do...i use clcat.items.add to display the item but the items is not display procedure TfrmSysConfig.FillInCheckListClCat; var sTable : string; sqlCat : TIBOQuery; iIndex :integer; lstCat : TStringList; begin if tblMain.FieldByName('POS_ReceiptCatBreakDown').AsString <> '' then begin sqlCat := TIBOQuery.Create(nil); sqlCat.IB_Connection := dmMain.db; lstCat := TStringList.Create; try sqlCat.SQL.Text := 'SELECT code FROM ' + cboCategory.Value; sqlCat.Open; while not sqlCat.Eof do begin clCat.Items.Add( sqlCat.FieldByName( 'Code' ).AsString ); sqlCat.Next; end; finally lstCat.Free; sqlCat.Free; end; end; end;

    Read the article

  • Preventing dictionary attacks on a web application

    - by Kevin Pang
    What's the best way to prevent a dictionary attack? I've thought up several implementations but they all seem to have some flaw in them: Lock out a user after X failed login attempts. Problem: easy to turn into a denial of service attack, locking out many users in a short amount of time. Incrementally increase response time per failed login attempt on a username. Problem: dictionary attacks might use the same password but different usernames. Incrementally increase response time per failed login attempt from an IP address. Problem: easy to get around by spoofing IP address. Incrementally increase response time per failed login attempt within a session. Problem: easy to get around by creating a dictionary attack that fires up a new session on each attempt.

    Read the article

  • Generating a set of files containing dumps of individual tables in a way that guarantees database co

    - by intuited
    I'd like to dump a MySQL database in such a way that a file is created for the definition of each table, and another file is created for the data in each table. I'd like this to be done in a way that guarantees database integrity by locking the entire database for the duration of the dump. What is the best way to do this? Similarly, what's the best way to lock the database while restoring a set of these dump files? edit I can't assume that mysql will have permission to write to files.

    Read the article

  • How to maipulate the shell output in php

    - by Mirage
    I am trying to write php script which does some shell functions like reporting. So i am starting with diskusage report I want in following format drive path ------------total-size --------free-space Nothing else My script is $output = shell_exec('df -h -T'); echo "<pre>$output</pre>"; and its ouput is like below Filesystem Type Size Used Avail Use% Mounted on /dev/sda6 ext3 92G 6.6G 81G 8% / none devtmpfs 3.9G 216K 3.9G 1% /dev none tmpfs 4.0G 176K 4.0G 1% /dev/shm none tmpfs 4.0G 1.1M 4.0G 1% /var/run none tmpfs 4.0G 0 4.0G 0% /var/lock none tmpfs 4.0G 0 4.0G 0% /lib/init/rw /dev/sdb1 ext3 459G 232G 204G 54% /media/Server /dev/sdb2 fuseblk 466G 254G 212G 55% /media/BACKUPS /dev/sda5 fuseblk 738G 243G 495G 33% /media/virtual_machines How can i convert that ouput into my forn\matted output

    Read the article

  • Fast way to pass a simple java object from one thread to another

    - by Adal
    I have a callback which receives an object. I make a copy of this object, and I must pass it on to another thread for further processing. It's very important for the callback to return as fast as possible. Ideally, the callback will write the copy to some sort of lock-free container. I only have the callback called from a single thread and one processing thread. I only need to pass a bunch of doubles to the other thread, and I know the maximum number of doubles (around 40). Any ideas? I'm not very familiar with Java, so I don't know the usual ways to pass stuff between threads.

    Read the article

  • Could not find generator mini_test:install

    - by David James
    I expected these generators to be available: $ rails g Usage: rails generate GENERATOR [args] [options] MiniTest: mini_test:controller mini_test:helper mini_test:install mini_test:mailer mini_test:model mini_test:scaffold So I ran: $ rails g mini_test:install But got this error: Could not find generator mini_test:install. As for my environment, here is the relevant portion of my Gemfile: group :test, :development do gem 'minitest-rails' end And the resulting portions of my Gemfile.lock: minitest (2.12.1) minitest-rails (0.0.7) minitest (~> 2.12) rails (~> 3.1) I am now in the process of debugging this. I would appreciate any tips. In any case, I will report back.

    Read the article

  • how to configure hibernate not to update @Version on each access to entity

    - by radai
    i have a simple query that returns an entity, and when i look at hibernate SQL output i see that when i execute this query hibernate updates the @Version field (on each consecutive read the @version field is updated). i dont modify anything in the entity i fetch, and i dont pass is as an argument to either persist or merge. this effectively means every read i make turns into a read+write. i've tried setting the lock mode t oboth NONE (jpa 2) and READ (jpa 1) to no avail. is there any way to achieve this? if so, is there any way to set this as the default behavior in persistence.xml in some way ? im using jpa2 over hibernate 3.6

    Read the article

  • How can I kill MySQL queries every 60 seconds in Windows?

    - by Ethan Allen
    I want to check my MySQL server every minute and kill queries that have run longer than 150 seconds. The main reason I want to do this is because I don't want queries from certain people to lock up the DB for everyone else. I know this is not the ultimate solution to the problem, but at least it's a fallback in case something goes wrong with a query. I don't have a slave DB (this is just an at-home project). I'd like to schedule a script to run that does this for me. I'm unfamiliar with Perl or Ruby and I need it done on my Windows 2008 Server box. I've looked into creating a simple cmd line script, but that doesn't seem to be possible. I know currently I can do something like this but I have to do it manually: mysqladmin processlist mysqladmin kill Anyone have any ideas or examples on how I could do this?

    Read the article

  • Is this query safe in SQL Server?

    - by xaw
    I have this SQL update query: UPDATE table1 SET table1.field1 = 1 WHERE table1.id NOT IN (SELECT table2.table1id FROM table2); Other portions of the application can add records to table2 which use the field table1id to reference table1. The goal here is to remove records from table1 which aren't referenced by table2. Does SQL Server automatically lock table2 with this kind of query so that a new record can't be added to table2 while executing this query? I've also considered: UPDATE table1 SET field1 = 1 WHERE 0 = (SELECT COUNT(*) FROM table2 WHERE table1.id = table2.table1id); Which seems possibly safer, but much slower (because a SELECT would be called on each row of table1 instead of just one select for the NOT IN)

    Read the article

  • .NET "Timer" would block other method calls?

    - by Ricky
    Hi guys: In ASP.NET 3.5, we suspect a delegate triggering by a "Timer" will block other method calls. From logs, some function calls will wait for the finishing of the delegate and continue to work. Is it true? If yes, what workaround can I do? PS: The delegate contains codes to use WCF to retrieve data and the following code private void Replace<T>(ref IList<T> src, IList<T> des) { lock(src) { while (src.Count > 0) { GC.SuppressFinalize(src.ElementAt(0)); src.RemoveAt(0); } GC.SuppressFinalize(src); src = des; } } Thanks a lot.

    Read the article

  • [MySQL, InnoDb] Rating place

    - by Pavel
    I'm trying to generate rating place table using following receipt http://stackoverflow.com/questions/1776821/assign-places-in-the-rating-mysql-php but my database is high loaded. I tried not to create table, but use MEMORY TABLE and update it using following SQL query insert into tops (uid) select uid from users order by exp desc; but got the following MySQL error Deadlock found when trying to get lock; try restarting transaction because there are too many queries until SQL select is being executed. How to solve this problem? P.S. CREATE TABLE tops as SELECT work almost fine except high server load... up to load average: 50 if tops are non-memory table. My table users has near 4.5 millions of rows. Thanks for any advices.

    Read the article

  • How do I prevent Window resizing when the Workstation is Locked then Unlocked?

    - by Terry
    We have an application that is run in multi-monitor environments. Users normally have the application dialog spread out to span multiple mointors. If the user locks the workstation, and then unlocks it, our application is told to resize. Our users find this behavior frustrating, as they then spend some time restoring the previous layout. We're not yet sure whether it is the graphics driver requesting the resize or Windows. Hopefully through this question, it will become clearer which component is responsible, Popular applications like (File) Explorer and Firefox behave the same way in this setup. To replicate just: open Explorer (Win+E) drag the Explorer window to being horizontally larger than 1 screen lock workstation (Win+L), unlock the application should now resize to being solely on 1 screen How do I prevent Window resizing when the Workstation is Locked then Unlocked? Will we need to code in checks for (un)locking? Is there another mechanism we're not aware of?

    Read the article

  • How to detect an active x component that does not respond any more?

    - by koschi
    My application is written in C++ and uses the Qt framework. I use the QAxWidget class to access an active x component. Now I need some kind of mechanism that notifies my application each time the active x component has crashed or does not respond any more (due to dead lock or infinite loop). (1) can easily been done by watching the external process of the active x component. But maybe there is a more elegant approach? But how can (2) be implemented?

    Read the article

  • How should I store Dynamically Changing Data into Server Cache?

    - by Scott
    Hey all, EDIT: Purpose of this Website: Its called Utopiapimp.com. It is a third party utility for a game called utopia-game.com. The site currently has over 12k users to it an I run the site. The game is fully text based and will always remain that. Users copy and paste full pages of text from the game and paste the copied information into my site. I run a series of regular expressions against the pasted data and break it down. I then insert anywhere from 5 values to over 30 values into the DB based on that one paste. I then take those values and run queries against them to display the information back in a VERY simple and easy to understand way. The game is team based and each team has 25 users to it. So each team is a group and each row is ONE users information. The users can update all 25 rows or just one row at a time. I require storing things into cache because the site is very slow doing over 1,000 queries almost every minute. So here is the deal. Imagine I have an excel spreadsheet with 100 columns and 5000 rows. Each row has two unique identifiers. One for the row it self and one to group together 25 rows a piece. There are about 10 columns in the row that will almost never change and the other 90 columns will always be changing. We can say some will even change in a matter of seconds depending on how fast the row is updated. Rows can also be added and deleted from the group, but not from the database. The rows are taken from about 4 queries from the database to show the most recent and updated data from the database. So every time something in the database is updated, I would also like the row to be updated. If a row or a group has not been updated in 12 or so hours, it will be taken out of Cache. Once the user calls the group again via the DB queries. They will be placed into Cache. The above is what I would like. That is the wish. In Reality, I still have all the rows, but the way I store them in Cache is currently broken. I store each row in a class and the class is stored in the Server Cache via a HUGE list. When I go to update/Delete/Insert items in the list or rows, most the time it works, but sometimes it throws errors because the cache has changed. I want to be able to lock down the cache like the database throws a lock on a row more or less. I have DateTime stamps to remove things after 12 hours, but this almost always breaks because other users are updating the same 25 rows in the group or just the cache has changed. This is an example of how I add items to Cache, this one shows I only pull the 10 or so columns that very rarely change. This example all removes rows not updated after 12 hours: DateTime dt = DateTime.UtcNow; if (HttpContext.Current.Cache["GetRows"] != null) { List<RowIdentifiers> pis = (List<RowIdentifiers>)HttpContext.Current.Cache["GetRows"]; var ch = (from xx in pis where xx.groupID == groupID where xx.rowID== rowID select xx).ToList(); if (ch.Count() == 0) { var ck = GetInGroupNotCached(rowID, groupID, dt); //Pulling the group from the DB for (int i = 0; i < ck.Count(); i++) pis.Add(ck[i]); pis.RemoveAll((x) => x.updateDateTime < dt.AddHours(-12)); HttpContext.Current.Cache["GetRows"] = pis; return ck; } else return ch; } else { var pis = GetInGroupNotCached(rowID, groupID, dt);//Pulling the group from the DB HttpContext.Current.Cache["GetRows"] = pis; return pis; } On the last point, I remove items from the cache, so the cache doesn't actually get huge. To re-post the question, Whats a better way of doing this? Maybe and how to put locks on the cache? Can I get better than this? I just want it to stop breaking when removing or adding rows.

    Read the article

  • Devise role based routing

    - by teknull
    I have an app with multiple users. Each user as a theoretical role (user, client, etc). I've designed a view/controller for each user type. I want to be able to login each type of user do a different root url and lock them to it. Originally I was going to add a column to Users in Devise called role and so I can differentiate the users. The problem I'm having is how to say in routes.rb if current_user.role == "client" root :to = 'controller#index' Once they are logged in to the page I also want to keep them from being able to visit any of my other paths ie: domain.com/calls domain.com/units I've been looking into cancan to run alongside Devise but I'm not sure if this is the answer.

    Read the article

  • Python Threading, loading one thread after another

    - by Michael
    Hi, I'm working on a media player and am able to load in a single .wav and play it. As seen in the code below. foo = wx.FileDialog(self, message="Open a .wav file...", defaultDir=os.getcwd(), defaultFile="", style=wx.FD_MULTIPLE) foo.ShowModal() queue = foo.GetPaths() self.playing_thread = threading.Thread(target=self.playFile, args=(queue[0], 'msg')) self.playing_thread.start() But the problem is, when I try to make the above code into a loop for multiple .wav files. Such that while playing_thread.isActive == True, create and .start() the thread. Then if .isActive == False, pop queue[0] and load the next .wav file. Problem is, my UI will lock up and I'll have to terminate the program. Any ideas would be appreciated.

    Read the article

  • unbuffered I/O in Linux

    - by stuck
    I'm writing lots and lots of data that will not be read again for weeks - as my program runs the amount of free memory on the machine (displayed with 'free' or 'top') drops very quickly, the amount of memory my app uses does not increase - neither does the amount of memory used by other processes. This leads me to believe the memory is being consumed by the filesystems cache - since I do not intend to read this data for a long time I'm hoping to bypass the systems buffers, such that my data is written directly to disk. I dont have dreams of improving perf or being a super ninja, my hope is to give a hint to the filesystem that I'm not going to be coming back for this memory any time soon, so dont spend time optimizing for those cases. On Windows I've faced similar problems and fixed the problem using FILE_FLAG_NO_BUFFERING|FILE_FLAG_WRITE_THROUGH - the machines memory was not consumed by my app and the machine was more usable in general. I'm hoping to duplicate the improvements I've seen but on Linux. On Windows there is the restriction of writing in sector sized pieces, I'm happy with this restriction for the amount of gain I've measured. is there a similar way to do this in Linux?

    Read the article

  • Building a J2EE dev/test setup on a single PC

    - by John
    It's been a while since I did Java work, and even then I was never responsible for starting a large project from the very start... there were test/staging/production systems already running, etc, etc. Now I am looking to start a J2EE project from scratch on my trusty workstation, which has never been used for Java development and runs Windows 7 64bit. First of all, I'll be getting Eclipse. As far as writing the code goes I'm pretty happy. And running it through Eclipse is OK, but what I'd really want is to have a VM running MySQL and TomCat on which I can properly deploy my project and run/debug it 'remotely' from my dev PC. And I guess this should be done using Ant instead of letting Eclipse build the WAR for me, so that I don't end up with a dependence on Eclipse. I'm certain Eclipse can do this, so you hit a button and it runs Ant scripts, deploys and debugs for instance, but very hazy on it. Are there any good guides on this? I don't want to be taught Java, or even Ant, but rather the 'glue' parts like getting my test VM up and running under Windows, getting a build/test/deploy/run pipeline running through Eclipse, etc. One point, I only plan to use Windows... hosting a Windows VM on my Windwos desktop. And while I can use command-line tools like ant/svn, I'm much more a GUI person who loves IDE integration... I'd rather this didn't end up an argument about Linux or Vi, etc! I am looking for free, but am a MAPS subscriber, and run Win7 Ultimate in case that makes a difference as far as free VM solutions.

    Read the article

  • why i'm permanently logged off my be

    - by Fixus
    Hello i have a problem with BE in my system. I'm permanently and automaticly logged out it after some time. 10-15 seconds, sometimes faster, sometimes slower. It's not connected with beeing idle cause I can be logged off even when I'm checking page tree or saving records I've set lock ip on 1 but it didn't help. The problem is most common under Firefox or Chome, what is strange under internet explorer i don't see it as often Other strange thing is that I see it on my live version but when I'm working on my local copy it doen not occure TYPO3 version 4.6.4

    Read the article

  • My iPhone app ran fine in simulator but crashed in device (iPod touch 3.1.2) test, I got the followi

    - by Mickey Shine
    I was running myapp on an iPod touch and I noticed it missed some libraries. Is that the reason? [Session started at 2010-03-19 15:57:04 +0800.] GNU gdb 6.3.50-20050815 (Apple version gdb-1128) (Fri Dec 18 10:08:53 UTC 2009) Copyright 2004 Free Software Foundation, Inc. GDB is free software, covered by the GNU General Public License, and you are welcome to change it and/or distribute copies of it under certain conditions. Type "show copying" to see the conditions. There is absolutely no warranty for GDB. Type "show warranty" for details. This GDB was configured as "--host=i386-apple-darwin --target=arm-apple-darwin".tty /dev/ttys007 Loading program into debugger… Program loaded. target remote-mobile /tmp/.XcodeGDBRemote-237-78 Switching to remote-macosx protocol mem 0x1000 0x3fffffff cache mem 0x40000000 0xffffffff none mem 0x00000000 0x0fff none run Running… [Switching to thread 11779] [Switching to thread 11779] sharedlibrary apply-load-rules all (gdb) continue warning: Unable to read symbols for "/Library/MobileSubstrate/MobileSubstrate.dylib" (file not found). 2010-03-19 15:57:18.892 myapp[2338:207] MS:Notice: Installing: com.yourcompany.myapp [myapp] (478.52) 2010-03-19 15:57:19.145 myapp[2338:207] MS:Notice: Loading: /Library/MobileSubstrate/DynamicLibraries/Backgrounder.dylib warning: Unable to read symbols for "/Library/MobileSubstrate/DynamicLibraries/Backgrounder.dylib" (file not found). warning: Unable to read symbols for "/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS3.1.2.sdk/usr/lib/libsubstrate.dylib" (file not found). MS:Warning: message not found [myappAppDelegate applicationWillResignActive:] MS:Warning: message not found [myappAppDelegate applicationDidBecomeActive:] 2010-03-19 15:57:19.550 myapp[2338:207] in FirstViewController 2010-03-19 15:57:20.344 myapp[2338:207] in load table view 2010-03-19 15:57:20.478 myapp[2338:207] in loading splash view 2010-03-19 15:57:22.793 myapp[2338:207] in set interface Program received signal: “0”. warning: check_safe_call: could not restore current frame

    Read the article

  • Do I need to syncronize thread access to an int

    - by Martin Harris
    I've just written a method that is called by multiple threads simultaneously and I need to keep track of when all the threads have completed, the code uses this pattern: private void RunReport() { _reportsRunning++; try { //code to run the report } finally { _reportsRunning--; } } This is the only place within the code that _reportsRunning's value is changed, and the method takes about a second to run. Occasionally when I have more than six or so threads running reports together the final result for _reportsRunning can get down to -1, if I wrap the calls to _runningReports++ and _runningReports-- in a lock then the behaviour appears to be correct and consistant. So, to the question: When I was learning multithreading in C++ I was taught that you didn't need to synchronize calls to increment and decrement operations because they were always one assembly instruction and therefore it was impossible for the thread to be switched out mid-call. Was I taught correctly, and if so how come that doesn't hold true for C#?

    Read the article

< Previous Page | 278 279 280 281 282 283 284 285 286 287 288 289  | Next Page >