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• Thought Oracle Usability Advisory Board Was Stuffy? Wrong. Justification for Attending OUAB: ROI

  - by ultan o'broin

  Looking for reasons tell your boss why your organization needs to join the Oracle Usability Advisory Board or why you need approval to attend one of its meetings (see the requirements)? Try phrases such as "Continued Return on Investment (ROI)", "Increased Productivity" or "Happy Workers". With OUAB your participation is about realizing and sustaining ROI across the entire applications life-cycle from input to designs to implementation choices and integration, usage and performance and on measuring and improving the onboarding and support experience. If you think this is a boring meeting of middle-aged people sitting around moaning about customizing desktop forms and why the BlackBerry is here to stay, think again! How about this for a rich agenda, all designed to engage the audience in a thought-provoking and feedback-illiciting day of swirling interactions, contextual usage, global delivery, mobility, consumerizationm, gamification and tailoring your implementation to reflect real users doing real work in real environments.  Foldable, rollable ereader devices provide a newspaper-like UK for electronic news. Or a way to wrap silicon chips, perhaps. Explored at the OUAB Europe Meeting (photograph from Terrace Restaurant in TVP. Nom.) At the 7 December 2012 OUAB Europe meeting in Oracle Thames Valley Park, UK, Oracle partners and customers stepped up to the mic and PPT decks with a range of facts and examples to astound any UX conference C-level sceptic. Over the course of the day we covered much ground, but it was all related in a contextual, flexibile, simplication, engagement way aout delivering results for business: that means solving problems. This means being about the user and their tasks and how to make design and technology transforms work into a productive activity that users and bean counters will be excited by. The sessions really gelled for me: 1. Mobile design patterns and the powerful propositions for customers and partners offered by using the design guidance with Oracle ADF Mobile. Customers' and partners' developers existing ADF developers are now productive, efficient ADF Mobile developers applying proven UX guidance using ADF Mobile components and other Oracle Fusion Middleware in the development toolkit. You can find the Mobile UX Design Patterns and Guidance on Building Mobile Apps on OTN. 2. Oracle Voice and Apps. How this medium offers so much potentual in the enterprise and offers a window in Fusion Apps cloud webservices, Oracle RightNow NLP and Nuance technology. Exciting stuff, demoed live on a mobile phone. Stay tuned for more features and modalities and how you can tailor your own apps experience.  3. Oracle RightNow Natural Language Processing (NLP) Virtual Assistant technology (Ella): how contextual intervention and learning from users sessions delivers a great personalized UX for users interacting with Ella, a fifth generation VA to solve problems and seek knowledge. 4. BYOD Keynote: A balanced keynote address contrasting Fujitsu's explaining of the conceprt, challenges, and trends and setting the expectation that BYOD must be embraced in a flexible way,  with the resolute, crafted high security enterprise requirements that nuancing the BYOD concept and proposals with the realities of their world of water tight information and device sharing policies. Fascinating stuff, as well providing anecdotes to make us thing about out own DYOD Deployments. One size does not fit all. 5. Icon Cultural Surveys Results and Insights Arising: Ever wondered about the cultural appropriateness of icons used in software UIs and how these icons assessed for global use? Or considered that social media "Like" icons might be  unacceptable hand gestures in culture or enterprise? Or do the old world icons like Save floppy disk icons still find acceptable? Well the survey results told you. Challenges must be tested, over time, and context of use is critical now, including external factors such as the internet and social media adoption. Indeed the fears about global rejection of the face and hand icons was not borne out, and some of the more anachronistic icons (checkbooks, microphones, real-to-real tape decks, 3.5" floppies for "save") have become accepted metaphors for current actions. More importantly the findings brought into focus the reason for OUAB - engage with and illicit feedback though working groups before we build anything. 6. EReaders and Oracle iBook: What is the uptake and trends of ereaders? And how about a demo of an iBook with enterprise apps content?  Well received by the audience, the session included a live running poll of ereader usage. 7. Gamification Design Jam: Fun, hands on event for teams of Oracle staff, partners and customers, actually building gamified flows, a practice that can be applied right away by customers and partners.  8. UX Direct: A new offering of usability best practices, coming to an external website for you in 2013. FInd a real user, observe their tasks, design and approve, build and measure. Simple stuff to improve apps implications no end. 9. FUSE (an internal term only, basically Fusion Simplified Experience): demo of the new Face of Fusion Applications: inherently mobile, simple to use, social, personalizable and FAST, three great demos from the HCM, CRM and ICT world on how these UX designs can be used in different ways. So, a powerful breadth and depth of UX solutions and opporunities for customers and partners to engage with and explore how they can make their users happy and benefit their business reaping continued ROI from those apps investments. Find out more about the OUAB and how to get involved here ... 

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• Computer Networks UNISA - Chap 15 &ndash; Network Management

  - by MarkPearl

  After reading this section you should be able to Understand network management and the importance of documentation, baseline measurements, policies, and regulations to assess and maintain a network’s health. Manage a network’s performance using SNMP-based network management software, system and event logs, and traffic-shaping techniques Identify the reasons for and elements of an asset managements system Plan and follow regular hardware and software maintenance routines Fundamentals of Network Management Network management refers to the assessment, monitoring, and maintenance of all aspects of a network including checking for hardware faults, ensuring high QoS, maintaining records of network assets, etc. Scope of network management differs depending on the size and requirements of the network. All sub topics of network management share the goals of enhancing the efficiency and performance while preventing costly downtime or loss. Documentation The way documentation is stored may vary, but to adequately manage a network one should at least record the following… Physical topology (types of LAN and WAN topologies – ring, star, hybrid) Access method (does it use Ethernet 802.3, token ring, etc.) Protocols Devices (Switches, routers, etc) Operating Systems Applications Configurations (What version of operating system and config files for serve / client software) Baseline Measurements A baseline is a report of the network’s current state of operation. Baseline measurements might include the utilization rate for your network backbone, number of users logged on per day, etc. Baseline measurements allow you to compare future performance increases or decreases caused by network changes or events with past network performance. Obtaining baseline measurements is the only way to know for certain whether a pattern of usage has changed, or whether a network upgrade has made a difference. There are various tools available for measuring baseline performance on a network. Policies, Procedures, and Regulations Following rules helps limit chaos, confusion, and possibly downtime. The following policies and procedures and regulations make for sound network management. Media installations and management (includes designing physical layout of cable, etc.) Network addressing policies (includes choosing and applying a an addressing scheme) Resource sharing and naming conventions (includes rules for logon ID’s) Security related policies Troubleshooting procedures Backup and disaster recovery procedures In addition to internal policies, a network manager must consider external regulatory rules. Fault and Performance Management After documenting every aspect of your network and following policies and best practices, you are ready to asses you networks status on an on going basis. This process includes both performance management and fault management. Network Management Software To accomplish both fault and performance management, organizations often use enterprise-wide network management software. There various software packages that do this, each collect data from multiple networked devices at regular intervals, in a process called polling. Each managed device runs a network management agent. So as not to affect the performance of a device while collecting information, agents do not demand significant processing resources. The definition of a managed devices and their data are collected in a MIB (Management Information Base). Agents communicate information about managed devices via any of several application layer protocols. On modern networks most agents use SNMP which is part of the TCP/IP suite and typically runs over UDP on port 161. Because of the flexibility and sophisticated network management applications are a challenge to configure and fine-tune. One needs to be careful to only collect relevant information and not cause performance issues (i.e. pinging a device every 5 seconds can be a problem with thousands of devices). MRTG (Multi Router Traffic Grapher) is a simple command line utility that uses SNMP to poll devices and collects data in a log file. MRTG can be used with Windows, UNIX and Linux. System and Event Logs Virtually every condition recognized by an operating system can be recorded. This is typically done using event logs. In Windows there is a GUI event log viewer. Similar information is recorded in UNIX and Linux in a system log. Much of the information collected in event logs and syslog files does not point to a problem, even if it is marked with a warning so it is important to filter your logs appropriately to reduce the noise. Traffic Shaping When a network must handle high volumes of network traffic, users benefit from performance management technique called traffic shaping. Traffic shaping involves manipulating certain characteristics of packets, data streams, or connections to manage the type and amount of traffic traversing a network or interface at any moment. Its goals are to assure timely delivery of the most important traffic while offering the best possible performance for all users. Several types of traffic prioritization exist including prioritizing traffic according to any of the following characteristics… Protocol IP address User group DiffServr VLAN tag in a Data Link layer frame Service or application Caching In addition to traffic shaping, a network or host might use caching to improve performance. Caching is the local storage of frequently needed files that would otherwise be obtained from an external source. By keeping files close to the requester, caching allows the user to access those files quickly. The most common type of caching is Web caching, in which Web pages are stored locally. To an ISP, caching is much more than just convenience. It prevents a significant volume of WAN traffic, thus improving performance and saving money. Asset Management Another key component in managing networks is identifying and tracking its hardware. This is called asset management. The first step to asset management is to take an inventory of each node on the network. You will also want to keep records of every piece of software purchased by your organization. Asset management simplifies maintaining and upgrading the network chiefly because you know what the system includes. In addition, asset management provides network administrators with information about the costs and benefits of certain types of hardware or software. Change Management Networks are always in a stage of flux with various aspects including… Software changes and patches Client Upgrades Shared Application Upgrades NOS Upgrades Hardware and Physical Plant Changes Cabling Upgrades Backbone Upgrades For a detailed explanation on each of these read the textbook (Page 750 – 761)

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• Long-running ASP.NET tasks

  - by John Leidegren

  I know there's a bunch of APIs out there that do this, but I also know that the hosting environment (being ASP.NET) puts restrictions on what you can reliably do in a separate thread. I could be completely wrong, so please correct me if I am, this is however what I think I know. A request typically timeouts after 120 seconds (this is configurable) but eventually the ASP.NET runtime will kill a request that's taking too long to complete. The hosting environment, typically IIS, employs process recycling and can at any point decide to recycle your app. When this happens all threads are aborted and the app restarts. I'm however not sure how aggressive it is, it would be kind of stupid to assume that it would abort a normal ongoing HTTP request but I would expect it to abort a thread because it doesn't know anything about the unit of work of a thread. If you had to create a programming model that easily and reliably and theoretically put a long running task, that would have to run for days, how would you accomplish this from within an ASP.NET application? The following are my thoughts on the issue: I've been thinking a long the line of hosting a WCF service in a win32 service. And talk to the service through WCF. This is however not very practical, because the only reason I would choose to do so, is to send tasks (units of work) from several different web apps. I'd then eventually ask the service for status updates and act accordingly. My biggest concern with this is that it would NOT be a particular great experience if I had to deploy every task to the service for it to be able to execute some instructions. There's also this issue of input, how would I feed this service with data if I had a large data set and needed to chew through it? What I typically do right now is this SELECT TOP 10 * FROM WorkItem WITH (ROWLOCK, UPDLOCK, READPAST) WHERE WorkCompleted IS NULL It allows me to use a SQL Server database as a work queue and periodically poll the database with this query for work. If the work item completed with success, I mark it as done and proceed until there's nothing more to do. What I don't like is that I could theoretically be interrupted at any point and if I'm in-between success and marking it as done, I could end up processing the same work item twice. I might be a bit paranoid and this might be all fine but as I understand it there's no guarantee that that won't happen... I know there's been similar questions on SO before but non really answers with a definitive answer. This is a really common thing, yet the ASP.NET hosting environment is ill equipped to handle long-running work. Please share your thoughts.

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• Mirth Transformer Error

  - by Ryan H

  I'm getting the following error when trying to convert HL7v3 to HL7v2 The message passed in is: <?xml version="1.0" encoding="UTF-8" standalone="no"?> <S:Envelope xmlns:S="http://schemas.xmlsoap.org/soap/envelope/"> <S:Body> <PRPA_IN201306UV02 xmlns="urn:hl7-org:v3" xmlns:ns2="urn:gov:hhs:fha:nhinc:common:nhinccommon" xmlns:ns3="urn:gov:hhs:fha:nhinc:common:patientcorrelationfacade" xmlns:ns4="http://schemas.xmlsoap.org/ws/2004/08/addressing" ITSVersion="XML_1.0"> <id extension="4ae5403:12752e71a17:-7b52" root="1.1.1"/> ... </PRPA_IN201306UV02> </S:Body> </S:Envelope> The error I get is: ERROR-300: Transformer error ERROR MESSAGE: Error evaluating transformer com.webreach.mirth.server.MirthJavascriptTransformerException: CHANNEL: v3v2ConversionResponseMessage CONNECTOR: sourceConnector SCRIPT SOURCE: LINE NUMBER: 5 DETAILS: TypeError: The prefix "S" for element "S:Envelope" is not bound. at com.webreach.mirth.server.mule.transformers.JavaScriptTransformer.evaluateScript(JavaScriptTransformer.java:460) at com.webreach.mirth.server.mule.transformers.JavaScriptTransformer.transform(JavaScriptTransformer.java:356) at org.mule.transformers.AbstractEventAwareTransformer.doTransform(AbstractEventAwareTransformer.java:48) at org.mule.transformers.AbstractTransformer.transform(AbstractTransformer.java:197) at org.mule.transformers.AbstractTransformer.transform(AbstractTransformer.java:200) at org.mule.impl.MuleEvent.getTransformedMessage(MuleEvent.java:251) at org.mule.routing.inbound.SelectiveConsumer.isMatch(SelectiveConsumer.java:61) at org.mule.routing.inbound.InboundMessageRouter.route(InboundMessageRouter.java:83) at org.mule.providers.AbstractMessageReceiver$DefaultInternalMessageListener.onMessage(AbstractMessageReceiver.java:493) at org.mule.providers.AbstractMessageReceiver.routeMessage(AbstractMessageReceiver.java:272) at org.mule.providers.AbstractMessageReceiver.routeMessage(AbstractMessageReceiver.java:231) at com.webreach.mirth.connectors.vm.VMMessageReceiver.getMessages(VMMessageReceiver.java:207) at org.mule.providers.TransactedPollingMessageReceiver.poll(TransactedPollingMessageReceiver.java:108) at org.mule.providers.PollingMessageReceiver.run(PollingMessageReceiver.java:90) at org.mule.impl.work.WorkerContext.run(WorkerContext.java:290) at edu.emory.mathcs.backport.java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:650) at edu.emory.mathcs.backport.java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:675) at java.lang.Thread.run(Unknown Source) When I remove the S: tag in front of the Envelope and Body and redefine the namespace to default, it gives me a new error "TypeError: The prefix "xsi" for attribute "xsi:nil" associated with an element type "targetMessage" is not bound." referring to <targetMessage xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:nil="true"/> As if mirth can't handle the namespaces being defined on the same line as the first use of that element. Any suggestions would be useful

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• Data validation best practices: how can I better construct user feedback?

  - by Cory Larson

  Data validation, whether it be domain object, form, or any other type of input validation, could theoretically be part of any development effort, no matter its size or complexity. I sometimes find myself writing informational or error messages that might seem harsh or demanding to unsuspecting users, and frankly I feel like there must be a better way to describe the validation problem to the user. I know that this topic is subjective and argumentative. StackOverflow might not be the proper channel for diving into this subject, but like I've mentioned, we all run into this at some point or another. There are so many StackExchange sites now; if there is a better one, feel free to share! Basically, I'm looking for good resources on data validation and user feedback that results from it at a theoretical level. Topics and questions I'm interested in are: Content Should I be describing what the user did correctly or incorrectly, or simply what was expected? How much detail can the user read before they get annoyed? (e.g. Is "Username cannot exceed 20 characters." enough, or should it be described more fully, such as "The username cannot be empty, and must be at least 6 characters but cannot exceed 30 characters."?) Grammar How do I decide between phrases like "must not," "may not," or "cannot"? Delivery This can depend on the project, but how should the information be delivered to the user? Should it be obtrusive (e.g. JavaScript alerts) or friendly? Should they be displayed prominently? Immediately (i.e. without confirmation steps, etc.)? Logging Do you bother logging validation errors? Internationalization Some cultures prefer or better understand directness over subtlety and vice-versa (e.g. "Don't do that!" vs. "Please check what you've done."). How do I cater to the majority of users? I may edit this list as I think more about the topic, but I'm genuinely interest in proper user feedback techniques. I'm looking for things like research results, poll results, etc. I've developed and refined my own techniques over the years that users seem to be okay with, but I work in an environment where the users prefer to adapt to what you give them over speaking up about things they don't like. I'm interested in hearing your experiences in addition to any resources to which you may be able to point me.

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• TcpListener is queuing connections faster than I can clear them

  - by Matthew Brindley

  As I understand it, TcpListener will queue connections once you call Start(). Each time you call AcceptTcpClient (or BeginAcceptTcpClient), it will dequeue one item from the queue. If we load test our TcpListener app by sending 1,000 connections to it at once, the queue builds far faster than we can clear it, leading (eventually) to timeouts from the client because it didn't get a response because its connection was still in the queue. However, the server doesn't appear to be under much pressure, our app isn't consuming much CPU time and the other monitored resources on the machine aren't breaking a sweat. It feels like we're not running efficiently enough right now. We're calling BeginAcceptTcpListener and then immediately handing over to a ThreadPool thread to actually do the work, then calling BeginAcceptTcpClient again. The work involved doesn't seem to put any pressure on the machine, it's basically just a 3 second sleep followed by a dictionary lookup and then a 100 byte write to the TcpClient's stream. Here's the TcpListener code we're using: // Thread signal. private static ManualResetEvent tcpClientConnected = new ManualResetEvent(false); public void DoBeginAcceptTcpClient(TcpListener listener) { // Set the event to nonsignaled state. tcpClientConnected.Reset(); listener.BeginAcceptTcpClient( new AsyncCallback(DoAcceptTcpClientCallback), listener); // Wait for signal tcpClientConnected.WaitOne(); } public void DoAcceptTcpClientCallback(IAsyncResult ar) { // Get the listener that handles the client request, and the TcpClient TcpListener listener = (TcpListener)ar.AsyncState; TcpClient client = listener.EndAcceptTcpClient(ar); if (inProduction) ThreadPool.QueueUserWorkItem(state => HandleTcpRequest(client, serverCertificate)); // With SSL else ThreadPool.QueueUserWorkItem(state => HandleTcpRequest(client)); // Without SSL // Signal the calling thread to continue. tcpClientConnected.Set(); } public void Start() { currentHandledRequests = 0; tcpListener = new TcpListener(IPAddress.Any, 10000); try { tcpListener.Start(); while (true) DoBeginAcceptTcpClient(tcpListener); } catch (SocketException) { // The TcpListener is shutting down, exit gracefully CheckBuffer(); return; } } I'm assuming the answer will be related to using Sockets instead of TcpListener, or at least using TcpListener.AcceptSocket, but I wondered how we'd go about doing that? One idea we had was to call AcceptTcpClient and immediately Enqueue the TcpClient into one of multiple Queue<TcpClient> objects. That way, we could poll those queues on separate threads (one queue per thread), without running into monitors that might block the thread while waiting for other Dequeue operations. Each queue thread could then use ThreadPool.QueueUserWorkItem to have the work done in a ThreadPool thread and then move onto dequeuing the next TcpClient in its queue. Would you recommend this approach, or is our problem that we're using TcpListener and no amount of rapid dequeueing is going to fix that?

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• Oracle Coding Standards Feature Implementation

  - by Mike Hofer

  Okay, I have reached a sort of an impasse. In my open source project, a .NET-based Oracle database browser, I've implemented a bunch of refactoring tools. So far, so good. The one feature I was really hoping to implement was a big "Global Reformat" that would make the code (scripts, functions, procedures, packages, views, etc.) standards compliant. (I've always been saddened by the lack of decent SQL refactoring tools, and wanted to do something about it.) Unfortunatey, I am discovering, much to my chagrin, that there doesn't seem to be any one widely-used or even "generally accepted" standard for PL-SQL. That kind of puts a crimp on my implementation plans. My search has been fairly exhaustive. I've found lots of conflicting documents, threads and articles and the opinions are fairly diverse. (Comma placement, of all things, seems to generate quite a bit of debate.) So I'm faced with a couple of options: Add a feature that lets the user customize the standard and then reformat the code according to that standard. —OR— Add a feature that lets the user customize the standard and simply generate a violations list like StyleCop does, leaving the SQL untouched. In my mind, the first option saves the end-users a lot of work, but runs the risk of modifying SQL in potentially unwanted ways. The second option runs the risk of generating lots of warnings and doing no work whatsoever. (It'd just be generally annoying.) In either scenario, I still have no standard to go by. What I'd need to know from you guys is kind of poll-ish, but kind of not. If you were going to use a tool of this nature, what parts of your SQL code would you want it to warn you about or fix? Again, I'm just at a loss due to a lack of a cohesive standard. And given that there isn't anything out there that's officially published by Oracle, I think this is something the community could weigh in on. Also, given the way that voting works on SO, the votes would help to establish the popularity of a given "refactoring." P.S. The engine parses SQL into an expression tree so it can robustly analyze the SQL and reformat it. There should be quite a bit that we can do to correct the format of the SQL. But I am thinking that for the first release of the thing, layout is the primary concern. Though it is worth noting that the thing already has refactorings for converting keywords to upper case, and identifiers to lower case.

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• iPhone: Speeding up a search that's polling 17,000 Core Data objects

  - by randombits

  I have a class that conforms to UISearchDisplayDelegate and contains a UISearchBar. This view is responsible for allowing the user to poll a store of about 17,000 objects that are currently managed by Core Data. Everytime the user types in a character, I created an instance of a SearchOperation (subclasses NSOperation) that queries Core Data to find results that might match the search. The code in the search controller looks something like: - (void)filterContentForSearchText:(NSString*)searchText scope:(NSString*)scope { // Update the filtered array based on the search text and scope in a secondary thread if ([searchText length] < 3) { [filteredList removeAllObjects]; // First clear the filtered array. [self setFilteredList:NULL]; [self.tableView reloadData]; return; } NSDictionary *searchdict = [NSDictionary dictionaryWithObjectsAndKeys:scope, @"scope", searchText, @"searchText", nil]; [aSearchQueue cancelAllOperations]; SearchOperation *searchOp = [[SearchOperation alloc] initWithDelegate:self dataDict:searchdict]; [aSearchQueue addOperation:searchOp]; } And my search is rather straight forward. SearchOperation is a subclass of NSOperation. I overwrote the main method with the following code: - (void)main { if ([self isCancelled]) { return; } NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init]; NSEntityDescription *entity = [NSEntityDescription entityForName:@"MyEntity" inManagedObjectContext:managedObjectContext]; NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init]; [fetchRequest setEntity:entity]; NSPredicate *predicate = NULL; predicate = [NSPredicate predicateWithFormat:@"(someattr contains[cd] %@)", searchText]; [fetchRequest setPredicate:predicate]; NSError *error = NULL; NSArray *fetchResults = [managedObjectContext executeFetchRequest:fetchRequest error:&error]; [fetchRequest release]; if (self.delegate != nil) [self.delegate didFinishSearching:fetchResults]; [pool drain]; } This code works, but it has several issues. It's slow. Even though I have the search happening in a separate thread other than the UI thread, querying 17,000 objects is clearly not optimal. If I'm not careful, crashes can happen. I set the max concurrent searches in my NSOperationQueue to 1 to avoid this. What else can I do to make this search faster? I think preloading all 17,000 objects into memory might be risky. There has to be a smarter way to conduct this search to give results back to the user faster.

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• How to write this JavaScript code without eval?

  - by karlthorwald

  How to write this JavaScript code without eval? var typeOfString = eval("typeof " + that.modules[modName].varName); if (typeOfString !== "undefined") { doSomething(); } The point is that the name of the var that I want to check for is in a string. Maybe it is simple but I don't know how. Edit: Thank you for the very interesting answers so far. I will follow your suggestions and integrate this into my code and do some testing and report. Could take a while. Edit2: I had another look at the could and maybe itis better I show you a bigger picture. I am greatful for the experts to explain so beautiful, it is better with more code: MYNAMESPACE.Loader = ( function() { function C() { this.modules = {}; this.required = {}; this.waitCount = 0; this.appendUrl = ''; this.docHead = document.getElementsByTagName('head')[0]; } function insert() { var that = this; //insert all script tags to the head now! //loop over all modules: for (var modName in this.required) { if(this.required.hasOwnProperty(modName)){ if (this.required[modName] === 'required') { this.required[modName] = 'loading'; this.waitCount = this.waitCount + 1; this.insertModule(modName); } } } //now poll until everything is loaded or //until timout this.intervalId = 0; var checkFunction = function() { if (that.waitCount === 0) { clearInterval(that.intervalId); that.onSuccess(); return; } for (var modName in that.required) { if(that.required.hasOwnProperty(modName)){ if (that.required[modName] === 'loading') { var typeOfString = eval("typeof " + that.modules[modName].varName); if (typeOfString !== "undefined") { //module is loaded! that.required[modName] = 'ok'; that.waitCount = that.waitCount - 1; if (that.waitCount === 0) { clearInterval(that.intervalId); that.onSuccess(); return; } } } } } }; //execute the function twice a second to check if all is loaded: this.intervalId = setInterval(checkFunction, 500); //further execution will be in checkFunction, //so nothing left to do here } C.prototype.insert = insert; //there are more functions here... return C; }()); var myLoader = new MYNAMESPACE.Loader(); //some more lines here... myLoader.insert();

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• BindException/Too many file open while using HttpClient under load

  - by Langali

  I have got 1000 dedicated Java threads where each thread polls a corresponding url every one second. public class Poller { public static Node poll(Node node) { GetMethod method = null; try { HttpClient client = new HttpClient(new SimpleHttpConnectionManager(true)); ...... } catch (IOException ex) { ex.printStackTrace(); } finally { method.releaseConnection(); } } } The threads are run every one second: for (int i=0; i <1000; i++) { MyThread thread = threads.get(i) // threads is a static field if(thread.isAlive()) { // If the previous thread is still running, let it run. } else { thread.start(); } } The problem is if I run the job every one second I get random exceptions like these: java.net.BindException: Address already in use INFO httpclient.HttpMethodDirector: I/O exception (java.net.BindException) caught when processing request: Address already in use INFO httpclient.HttpMethodDirector: Retrying request But if I run the job every 2 seconds or more, everything runs fine. I even tried shutting down the instance of SimpleHttpConnectionManager() using shutDown() with no effect. If I do netstat, I see thousands of TCP connections in TIME_WAIT state, which means they are have been closed and are clearing up. So to limit the no of connections, I tried using a single instance of HttpClient and use it like this: public class MyHttpClientFactory { private static MyHttpClientFactory instance = new HttpClientFactory(); private MultiThreadedHttpConnectionManager connectionManager; private HttpClient client; private HttpClientFactory() { init(); } public static HttpClientFactory getInstance() { return instance; } public void init() { connectionManager = new MultiThreadedHttpConnectionManager(); HttpConnectionManagerParams managerParams = new HttpConnectionManagerParams(); managerParams.setMaxTotalConnections(1000); connectionManager.setParams(managerParams); client = new HttpClient(connectionManager); } public HttpClient getHttpClient() { if (client != null) { return client; } else { init(); return client; } } } However after running for exactly 2 hours, it starts throwing 'too many open files' and eventually cannot do anything at all. ERROR java.net.SocketException: Too many open files INFO httpclient.HttpMethodDirector: I/O exception (java.net.SocketException) caught when processing request: Too many open files INFO httpclient.HttpMethodDirector: Retrying request I should be able to increase the no of connections allowed and make it work, but I would just be prolonging the evil. Any idea what is the best practise to use HttpClient in a situation like above? Btw, I am still on HttpClient3.1.

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• modify this code .. please help me?

  - by Sam

  i wana modify this code from static choices to dynamic this for 3 choices var PollhttpObject=null; function DoVote() {if(document.getElementById('PollRadio1').checke d)DoVote_Submit(1);else if(document.getElementById('PollRadio2').checked)DoVote_Submit(2);else if(document.getElementById('PollRadio3').checked)DoVote_Submit(3);else alert('?????: ?????? ?????? ??? ?????????? ??????? ?? ????? ??? ?? ???????');return false;} function DisbalePoll(TheCase) {document.getElementById('VoteBttn').onclick=function(){alert('!?????? ??? ?? ??????? ??????');} document.getElementById('PollRadio1').disabled='true';document.getElementById('PollRadio2').disabled='true';document.getElementById('PollRadio3').disabled='true';if(TheCase=='EXPIRED') {document.getElementById('VoteBttn').src='images/design/VoteBttn_OFF.jpg';document.getElementById('ResultBttn').src='images/design/ResultsBttn_OFF.jpg';document.getElementById('VoteBttn').onclick='';document.getElementById('ResultBttn').onclick='';document.getElementById('ResultBttn').style.cursor='';document.getElementById('VoteBttn').style.cursor='';}} function DoVote_Submit(VoteID) {if(VoteID!=0)DisbalePoll();try{PollhttpObject=getHTTPObject();if(PollhttpObject!=null) {PollhttpObject.onreadystatechange=PollOutput;PollhttpObject.open("GET","Ajax.aspx?ACTION=POLL&VOTEID="+ VoteID+"&RND="+ Math.floor(Math.random()*10001),true);PollhttpObject.send(null);}} catch(e){} return false;} function PollOutput(){if(PollhttpObject.readyState==4) {var SearchResult=PollhttpObject.responseText;document.getElementById('PollProgress').style.display='none';document.getElementById('PollFormDiv').style.display='block';if(SearchResult.length=2&&SearchResult.substr(0,2)=='OK') {var ReturnedValue=SearchResult.split("#");document.getElementById('PollBar1').style.width=0+'px';document.getElementById('PollBar2').style.width=0+'px';document.getElementById('PollBar3').style.width=0+'px';document.getElementById('PollRate1').innerHTML="0 (0%)";document.getElementById('PollRate2').innerHTML="0 (0%)";document.getElementById('PollRate3').innerHTML="0 (0%)";window.setTimeout('DrawPollBars(0, '+ ReturnedValue[1]+', 0, '+ ReturnedValue[2]+', 0, '+ ReturnedValue[3]+')',150);} else if(SearchResult.length=2&&SearchResult.substr(0,2)=='NO') {alert("?????: ??? ??? ???????? ?????");}} else {document.getElementById('PollProgress').style.display='block';document.getElementById('PollFormDiv').style.display='none';}} function DrawPollBars(Bar1Var,Bar1Width,Bar2Var,Bar2Width,Bar3Var,Bar3Width) {var TotalVotes=parseInt(Bar1Width)+parseInt(Bar2Width)+parseInt(Bar3Width);var IncVal=parseFloat(TotalVotes/10);var NewBar1Width=0;var NewBar2Width=0;var NewBar3Width=0;var Bar1NextVar;var Bar2NextVar;var Bar3NextVar;if(parseInt(parseInt(Bar1Var)*200/TotalVotes)0)NewBar1Width=parseInt(Bar1Var)*200/TotalVotes;else if(Bar1Var0)NewBar1Width=1;else NewBar1Width=0;if(parseInt(parseInt(Bar2Var)*200/TotalVotes)0)NewBar2Width=parseInt(Bar2Var)*200/TotalVotes;else if(Bar2Var0)NewBar2Width=1;else NewBar2Width=0;if(parseInt(parseInt(Bar3Var)*200/TotalVotes)0)NewBar3Width=parseInt(Bar3Var)*200/TotalVotes;else if(Bar3Var0)NewBar3Width=1;else NewBar3Width=0;document.getElementById('PollBar1').style.width=NewBar1Width+'px';document.getElementById('PollBar2').style.width=NewBar2Width+'px';document.getElementById('PollBar3').style.width=NewBar3Width+'px';document.getElementById('PollRate1').innerHTML=parseFloat(Bar1Var).toFixed(0)+" ("+ parseFloat(parseFloat(Bar1Var)/TotalVotes*100).toFixed(1)+"%)";document.getElementById('PollRate2').innerHTML=parseFloat(Bar2Var).toFixed(0)+" ("+ parseFloat(parseFloat(Bar2Var)/TotalVotes*100).toFixed(1)+"%)";document.getElementById('PollRate3').innerHTML=parseFloat(Bar3Var).toFixed(0)+" ("+ parseFloat(parseFloat(Bar3Var)/TotalVotes*100).toFixed(1)+"%)";if(Bar1Var!=Bar1Width||Bar2Var!=Bar2Width||Bar3Var!=Bar3Width) {if(parseFloat(Bar1Var)+IncVal<=parseInt(Bar1Width))Bar1NextVar=parseFloat(Bar1Var)+IncVal;else Bar1NextVar=Bar1Width;if(parseFloat(Bar2Var)+IncVal<=parseInt(Bar2Width))Bar2NextVar=parseFloat(Bar2Var)+IncVal;else Bar2NextVar=Bar2Width;if(parseFloat(Bar3Var)+IncVal<=parseInt(Bar3Width))Bar3NextVar=parseFloat(Bar3Var)+IncVal;else Bar3NextVar=Bar3Width;window.setTimeout('DrawPollBars('+ Bar1NextVar+', '+ Bar1Width+', '+ Bar2NextVar+', '+ Bar2Width+', '+ Bar3NextVar+', '+ Bar3Width+')',80); }}

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• XmlHttpRequest bug?

  - by valdo

  Hello all. I'm writing a program that among other things needs to download a file given its URL. I'm too lazy to implement the Http/Https protocols manually, so that I needed some library/object/function that'll do the job. Critical requirement: The download must be asynchronous. That is, the thread that issued the download must be able to do something else "while" downloading the file, plus the download must be able to be aborted anytime without any barbaric side effects (such as internal call to TerminateThread). Nice-to-have requirements: Should be able to download the file "into memory". Means - read the contents of the file as they arrive, not necessarily save it into some "file system" file. It'd be nice to have some convenient Win32 progress notification mechanism (waitable event, semahpore, completion port, etc.), rather than just periodically polling the download status. I've chosen the XmlHttpRequest COM object to do the work. It seemed to work fine enough, plus it supported asynchronous mode. However I noticed that after some period it just stops working. That is, after several successful file downloads it stops downloading anything. I periodically poll it to get its status, it reports "in-progress", but nothing actually happens, and there's no network activity. Moreover, when the same process creates another instance of XmlHttpRequest object to perform new downloads - the effect is the same. The object reports "in progress", whereas it doesn't even try to connect to the server (according to network sniffers and system TCP state). The only way to make this object work back is to restart the process. This makes me suspect that there's a sort of a bug (sorry, I meant undocumented feature) in the object. Also it's not a bug at the level of an individual object, since the problem persists when the object is destroyed and another one is created. It's probably some global state of the DLL that implements this object. Does anyone know something about this? Is this a known bug? I'm pretty sure there's no chance that I have another bug in my code, because of which it seems to me to be the bug is in the XmlHttpRequest. I've done enoughtests and spent time with the debugger to conclude without reasonable doubt that it's just the object stops working. BTW, while the object should work, I do all the waiting via MsgWaitXXXX API calls. So that if this object needs the message loop to work properly (for instance, it may create a hidden notification window and bind it to a socket via WSAAsyncSelect) - I give it the opportunity.

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• Are there any platforms where using structure copy on an fd_set (for select() or pselect()) causes p

  - by Jonathan Leffler

  The select() and pselect() system calls modify their arguments (the 'struct fd_set *' arguments), so the input value tells the system which file descriptors to check and the return values tell the programmer which file descriptors are currently usable. If you are going to call them repeatedly for the same set of file descriptors, you need to ensure that you have a fresh copy of the descriptors for each call. The obvious way to do that is to use a structure copy: struct fd_set ref_set_rd; struct fd_set ref_set_wr; struct fd_set ref_set_er; ... ...code to set the reference fd_set_xx values... ... while (!done) { struct fd_set act_set_rd = ref_set_rd; struct fd_set act_set_wr = ref_set_wr; struct fd_set act_set_er = ref_set_er; int bits_set = select(max_fd, &act_set_rd, &act_set_wr, &act_set_er, &timeout); if (bits_set > 0) { ...process the output values of act_set_xx... } } My question: Are there any platforms where it is not safe to do a structure copy of the struct fd_set values as shown? I'm concerned lest there be hidden memory allocation or anything unexpected like that. (There are macros/functions FD_SET(), FD_CLR(), FD_ZERO() and FD_ISSET() to mask the internals from the application.) I can see that MacOS X (Darwin) is safe; other BSD-based systems are likely to be safe, therefore. You can help by documenting other systems that you know are safe in your answers. (I do have minor concerns about how well the struct fd_set would work with more than 8192 open file descriptors - the default maximum number of open files is only 256, but the maximum number is 'unlimited'. Also, since the structures are 1 KB, the copying code is not dreadfully efficient, but then running through a list of file descriptors to recreate the input mask on each cycle is not necessarily efficient either. Maybe you can't do select() when you have that many file descriptors open, though that is when you are most likely to need the functionality.) There's a related SO question - asking about 'poll() vs select()' which addresses a different set of issues from this question.

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• Refactoring Singleton Overuse

  - by drharris

  Today I had an epiphany, and it was that I was doing everything wrong. Some history: I inherited a C# application, which was really just a collection of static methods, a completely procedural mess of C# code. I refactored this the best I knew at the time, bringing in lots of post-college OOP knowledge. To make a long story short, many of the entities in code have turned out to be Singletons. Today I realized I needed 3 new classes, which would each follow the same Singleton pattern to match the rest of the software. If I keep tumbling down this slippery slope, eventually every class in my application will be Singleton, which will really be no logically different from the original group of static methods. I need help on rethinking this. I know about Dependency Injection, and that would generally be the strategy to use in breaking the Singleton curse. However, I have a few specific questions related to this refactoring, and all about best practices for doing so. How acceptable is the use of static variables to encapsulate configuration information? I have a brain block on using static, and I think it is due to an early OO class in college where the professor said static was bad. But, should I have to reconfigure the class every time I access it? When accessing hardware, is it ok to leave a static pointer to the addresses and variables needed, or should I continually perform Open() and Close() operations? Right now I have a single method acting as the controller. Specifically, I continually poll several external instruments (via hardware drivers) for data. Should this type of controller be the way to go, or should I spawn separate threads for each instrument at the program's startup? If the latter, how do I make this object oriented? Should I create classes called InstrumentAListener and InstrumentBListener? Or is there some standard way to approach this? Is there a better way to do global configuration? Right now I simply have Configuration.Instance.Foo sprinkled liberally throughout the code. Almost every class uses it, so perhaps keeping it as a Singleton makes sense. Any thoughts? A lot of my classes are things like SerialPortWriter or DataFileWriter, which must sit around waiting for this data to stream in. Since they are active the entire time, how should I arrange these in order to listen for the events generated when data comes in? Any other resources, books, or comments about how to get away from Singletons and other pattern overuse would be helpful.

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• DataGridView live display of datatable using virtual mode

  - by Chris

  I have a DataGridView that will display records (log entries) from a database. The amount of records that can exist at a time is very large. I would like to use the virtual mode feature of the DataGridView to display a page of data, and to minimize the amount of data that has to be transferred across a network at a given time. Polling for data is out of the question. There will be several clients running at a time, all of which are on the same network and viewing the records. If they all poll for data, the network will run very slowly. The data is read-only to the user; they won't be able to edit any of it, just view it. I need to know when updates occur in the database, and I need to update the screen with those updates accordingly using virtual mode. If a page of data a user is viewing contains data that has change, he/she will see those updates on that page. If updates were made to data in the database, but not in the data the user is viewing, then not much really changes on the user screen (Maybe just the scroll bar if records were added or removed). My current approach is using SQL server change tracking with the sync framework. Each client has a local SQL Server CE instance and database file that is kept in sync with the main database server. I use the information from the synchronization event to see if any changes were made to the main database and were sync'ed to the client. I need to use the DataGridView virtual mode here because I can't have thousands of records loaded into the DataGridView at once, otherwise memory usage goes through the roof. The main challenge right now is knowing how to use virtual mode to provide a seamless experience to the user by allowing them to scroll up and down through the records, and also have records update on the fly without interfering with the user inappropriately. Has anybody dealt with this issue before, and if so, where I can see how they did it? I've gone through some of the MSDN documentation and examples on virtual mode. So far, I haven't found documentation and/or examples on their site that explains how to do what I am trying to accomplish.

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• BIND DNS Master with Zerigo Slaves - BIND won't update the slave servers

  - by Anthony

  I've tried to resolve this myself and have looked through Google and Stack but haven't found the answer I'm looking for. Currently on a VPS server I have BIND DNS installed as a MASTER DNS Server. I use Zerigo's DNS service as SLAVE servers for public use: The Master doesn't receive queries - It's job is to simply create and modify DNS entries locally of which the SLAVE use to serve. Here is an excerpt of the BIND log, I set it to INFO event logging: 14-Apr-2012 23:00:00.234 general: info: received control channel command 'reload' 14-Apr-2012 23:00:00.234 general: info: loading configuration from 'C:\DNS\BIND\etc\named.conf' 14-Apr-2012 23:00:00.234 general: info: using default UDP/IPv4 port range: [1024, 65535] 14-Apr-2012 23:00:00.234 general: info: using default UDP/IPv6 port range: [1024, 65535] 14-Apr-2012 23:00:00.250 general: info: reloading configuration succeeded 14-Apr-2012 23:00:00.250 general: info: reloading zones succeeded 14-Apr-2012 23:16:22.750 xfer-out: info: client 174.36.24.251#47135: transfer of 'ajmakeup.com/IN': AXFR started 14-Apr-2012 23:16:22.750 xfer-out: info: client 174.36.24.251#47135: transfer of 'ajmakeup.com/IN': AXFR ended 14-Apr-2012 23:16:23.015 xfer-out: info: client 68.71.141.22#36212: transfer of 'ajmakeup.com/IN': AXFR started 14-Apr-2012 23:16:23.031 xfer-out: info: client 68.71.141.22#36212: transfer of 'ajmakeup.com/IN': AXFR ended As you can see there is no problem with Zerigo's DNS servers requesting new DNS data, when I force a reload that is; I don't believe, as per the way they are set as SLAVE, that they poll for changes. However the problem is the other way; the MASTER is not updating the SLAVE servers when reload is run (on the MASTER); it is a batch on a 15 minute timer. Below is my NAMED.CONF: key "rndc-key" { algorithm hmac-md5; secret "REMOVED FOR SECURITY"; }; acl "trusted" { 174.36.24.251/32; 68.71.141.22/32; localhost; }; options { version "not currently available"; directory "C:\DNS\BIND\etc"; allow-query { trusted; }; }; controls { inet 127.0.0.1 port 953 allow { 127.0.0.1; } keys { "rndc-key"; }; }; logging{ channel simple_log { file "C:\DNS\BIND\logging\bind.log" versions 3 size 5m; severity info; print-time yes; print-severity yes; print-category yes; }; category default{ simple_log; }; }; zone "ajmakeup.com" in { type master; file "c:\dns\BIND\zones\db.ajmakeup.com.txt"; allow-transfer { 174.36.24.251; 68.71.141.22; }; allow-update { none; }; }; Does my problem have something to do with 'allow-query' under options? You will notice that 'allow-transfer' is set explicitly on each DNS zone. In case you need it here is my RNDC.CONF: key "rndc-key" { algorithm hmac-md5; secret "REMOVED FOR SECURITY"; }; options { default-key "rndc-key"; default-server 127.0.0.1; default-port 953; }; server localhost { key "rndc-key"; }; Note: I am using WebsitePanel as my hosting panel and is such why it creates the zone enteries the way it does. Although I know I can change this behaviour, I do not wish to do so nor do I believe is the root of the problem. Thanks for your help.

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• Monit won't run

  - by Yaniro

  I have two identical EC2 instances (the second is a replica of the first), running Gentoo. The first instance has monit running which monitors a single process and some system resources and functions great. In the second instance, monit runs but quits right away. The configuration is similar on both instances so are the versions of monit. monit.log shows: [GMT Oct 3 08:36:41] info : monit daemon with PID 5 awakened Final lines on strace monit show: write(2, "monit daemon with PID 5 awakened"..., 33monit daemon with PID 5 awakened ) = 33 time(NULL) = 1349252827 open("/etc/localtime", O_RDONLY) = 4 fstat64(4, {st_mode=S_IFREG|0644, st_size=118, ...}) = 0 fstat64(4, {st_mode=S_IFREG|0644, st_size=118, ...}) = 0 mmap2(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0xb773a000 read(4, "TZif2\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\1\0\0\0\1\0\0\0\0"..., 4096) = 118 _llseek(4, -6, [112], SEEK_CUR) = 0 read(4, "\nGMT0\n", 4096) = 6 close(4) = 0 munmap(0xb773a000, 4096) = 0 write(3, "[GMT Oct 3 08:27:07] info :"..., 33) = 33 write(3, "monit daemon with PID 5 awakened"..., 33) = 33 waitpid(-1, NULL, WNOHANG) = -1 ECHILD (No child processes) close(3) = 0 exit_group(0) = ? No core dumps (ulimit -c shows unlimited) monit -v shows: monit: Debug: Adding host allow 'localhost' monit: Debug: Skipping redundant host 'localhost' monit: Debug: Skipping redundant host 'localhost' monit: Debug: Adding credentials for user 'xxxx'. Runtime constants: Control file = /etc/monitrc Log file = /var/log/monit/monit.log Pid file = /var/run/monit.pid Id file = /var/run/monit.pid Debug = True Log = True Use syslog = False Is Daemon = True Use process engine = True Poll time = 30 seconds with start delay 0 seconds Expect buffer = 256 bytes Event queue = base directory /var/monit with 100 slots Mail server(s) = xx.xxx.xx.xxx with timeout 30 seconds Mail from = (not defined) Mail subject = (not defined) Mail message = (not defined) Start monit httpd = True httpd bind address = Any/All httpd portnumber = 2812 httpd signature = True Use ssl encryption = False httpd auth. style = Basic Authentication and Host/Net allow list Alert mail to = [email protected] Alert on = All events The service list contains the following entries: System Name = xxxx Monitoring mode = active CPU wait limit = if greater than 20.0% 1 times within 1 cycle(s) then alert else if succeeded 1 times within 1 cycle(s) then alert CPU system limit = if greater than 30.0% 1 times within 1 cycle(s) then alert else if succeeded 1 times within 1 cycle(s) then alert CPU user limit = if greater than 70.0% 1 times within 1 cycle(s) then alert else if succeeded 1 times within 1 cycle(s) then alert Swap usage limit = if greater than 25.0% 1 times within 1 cycle(s) then alert else if succeeded 1 times within 1 cycle(s) then alert Memory usage limit = if greater than 75.0% 1 times within 1 cycle(s) then alert else if succeeded 1 times within 1 cycle(s) then alert Load avg. (5min) = if greater than 2.0 1 times within 1 cycle(s) then alert else if succeeded 1 times within 1 cycle(s) then alert Load avg. (1min) = if greater than 4.0 1 times within 1 cycle(s) then alert else if succeeded 1 times within 1 cycle(s) then alert Process Name = xxxx Group = server Pid file = /var/run/xxxx.pid Monitoring mode = active Start program = '/etc/init.d/xxxx restart' timeout 20 second(s) Stop program = '/etc/init.d/xxxx stop' timeout 30 second(s) Existence = if does not exist 1 times within 1 cycle(s) then restart else if succeeded 1 times within 1 cycle(s) then alert Pid = if changed 1 times within 1 cycle(s) then alert Ppid = if changed 1 times within 1 cycle(s) then alert Timeout = If restarted 3 times within 5 cycle(s) then unmonitor Alert mail to = [email protected] Alert on = All events Alert mail to = [email protected] Alert on = All events ------------------------------------------------------------------------------- monit daemon with PID 5 awakened Ran emerge --sync before emerge -va monit which installed monit v5.3.2. When that didn't work i've downloaded v5.5 from their website and compiled from source which did not work either.

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• Can't launch glassfish on ec2 - can't open port

  - by orange80

  I'm trying to start glassfish on an EBS-based AMI of Ubuntu 10.04 64-bit. I have used glassfish on non-ec2 servers with no problems, but on ec2 I get this message: $ sudo -u glassfish bin/asadmin start-domain domain1 There is a process already using the admin port 4848 -- it probably is another instance of a GlassFish server. Command start-domain failed. I know that ec2 has requires that firewall rules be modified using ec2-authorize to let outside traffic thru the firewall, as I had to do to make ssh work. This still doesn't explain the port error when all I'm trying to do is start glassfish so I can try $ wget localhost:8080and make sure it's working. This is very frustrating and I'd really appreciate any help. Thanks. FINAL UPDATE: Sorry if you came here looking for answers. I never figured out what was causing the problem. I created another fresh instance, installed the same stuff, and Glassfish worked perfectly. Something obviously got boned during installation, but I have no idea what. I guess it will remain a mystery. UPDATE: Here's what I get from netstat: # netstat -nuptl Active Internet connections (only servers) Proto Recv-Q Send-Q Local Address Foreign Address State PID/Program name tcp 0 0 0.0.0.0:22 0.0.0.0:* LISTEN 462/sshd tcp6 0 0 :::22 :::* LISTEN 462/sshd udp 0 0 0.0.0.0:5353 0.0.0.0:* 483/avahi-daemon: r udp 0 0 0.0.0.0:1194 0.0.0.0:* 589/openvpn udp 0 0 0.0.0.0:37940 0.0.0.0:* 483/avahi-daemon: r udp 0 0 0.0.0.0:68 0.0.0.0:* 377/dhclient3 UPDATE: One more thing... I know that the "net.ipv6.bindv6only" kernel option can cause problems with java networking, so I did set this: # sysctl -w net.ipv6.bindv6only=0 UPDATE: I also verified that it has nothing at all to do with the port number (4848). As you can see here, when I changed the admin-listener port in domain.xml to 4949, I get a similar message: # sudo -u glassfish bin/asadmin start-domain domain1 There is a process already using the admin port 4949 -- it probably is another instance of a GlassFish server. Command start-domain failed. UPDATE: Here are the contents of /etc/hosts: 127.0.0.1 localhost # The following lines are desirable for IPv6 capable hosts ::1 ip6-localhost ip6-loopback fe00::0 ip6-localnet ff00::0 ip6-mcastprefix ff02::1 ip6-allnodes ff02::2 ip6-allrouters ff02::3 ip6-allhosts I should mention that I have another Ubuntu Lucid 10.04 64-bit slice that is NOT hosted on ec2, and set it up the exact same way with no problems whatsoever. Also server.log doesn't offer much insight either: # cat ./server.log Nov 20, 2010 8:46:49 AM com.sun.enterprise.admin.launcher.GFLauncherLogger info INFO: JVM invocation command line: /usr/lib/jvm/java-6-sun-1.6.0.22/bin/java -cp /opt/glassfishv3/glassfish/modules/glassfish.jar -XX:+UnlockDiagnosticVMOptions -XX:MaxPermSize=192m -XX:NewRatio=2 -XX:+LogVMOutput -XX:LogFile=/opt/glassfishv3/glassfish/domains/domain1/logs/jvm.log -Xmx512m -client -javaagent:/opt/glassfishv3/glassfish/lib/monitor/btrace-agent.jar=unsafe=true,noServer=true -Dosgi.shell.telnet.maxconn=1 -Djdbc.drivers=org.apache.derby.jdbc.ClientDriver -Dfelix.fileinstall.dir=/opt/glassfishv3/glassfish/modules/autostart/ -Djavax.net.ssl.keyStore=/opt/glassfishv3/glassfish/domains/domain1/config/keystore.jks -Dosgi.shell.telnet.port=6666 -Djava.security.policy=/opt/glassfishv3/glassfish/domains/domain1/config/server.policy -Dfelix.fileinstall.poll=5000 -Dcom.sun.aas.instanceRoot=/opt/glassfishv3/glassfish/domains/domain1 -Dcom.sun.enterprise.config.config_environment_factory_class=com.sun.enterprise.config.serverbeans.AppserverConfigEnvironmentFactory -Dosgi.shell.telnet.ip=127.0.0.1 -Djava.endorsed.dirs=/opt/glassfishv3/glassfish/modules/endorsed:/opt/glassfishv3/glassfish/lib/endorsed -Dcom.sun.aas.installRoot=/opt/glassfishv3/glassfish -Djava.ext.dirs=/usr/lib/jvm/java-6-sun-1.6.0.22/lib/ext:/usr/lib/jvm/java-6-sun-1.6.0.22/jre/lib/ext:/opt/glassfishv3/glassfish/domains/domain1/lib/ext -Dfelix.fileinstall.bundles.new.start=true -Djavax.net.ssl.trustStore=/opt/glassfishv3/glassfish/domains/domain1/config/cacerts.jks -Dcom.sun.enterprise.security.httpsOutboundKeyAlias=s1as -Djava.security.auth.login.config=/opt/glassfishv3/glassfish/domains/domain1/config/login.conf -DANTLR_USE_DIRECT_CLASS_LOADING=true -Dfelix.fileinstall.debug=1 -Dorg.glassfish.web.rfc2109_cookie_names_enforced=false -Djava.library.path=/opt/glassfishv3/glassfish/lib:/usr/lib/jvm/java-6-sun-1.6.0.22/jre/lib/amd64/server:/usr/lib/jvm/java-6-sun-1.6.0.22/jre/lib/amd64:/usr/lib/jvm/java-6-sun-1.6.0.22/lib/amd64:/usr/java/packages/lib/amd64:/usr/lib64:/lib64:/lib:/usr/lib com.sun.enterprise.glassfish.bootstrap.ASMain -domainname domain1 -asadmin-args start-domain,,,domain1 -instancename server -verbose false -debug false -asadmin-classpath /opt/glassfishv3/glassfish/modules/admin-cli.jar -asadmin-classname com.sun.enterprise.admin.cli.AsadminMain -upgrade false -domaindir /opt/glassfishv3/glassfish/domains/domain1 -read-stdin true

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• Riak "error":"insufficient_vnodes_available"

  - by Wolfiem

  We have 4 nodes Riak installation. They are running on Ubuntu 12.04 LTS Precise installed servers. We have installed 1.1.4 at August 1st 2012 and upgraded 1.2.0 when its available. Server names are: f1 - 10.10.0.12 - This is the first installed server. We have joined other ones to this server. This also serves Riak control. s2 - 10.10.0.22 - s3 - 10.10.0.23 - s4 - 10.10.0.24 - This server also serves Riak control. This morning we've seen "insufficient nodes available" error at our applications log and restarted all nodes. 3 of them became available except "f1" UPDATE : while I prepare this message live 3 nodes became unavailable and need restart Riak. wolfiem@f01:~$ sudo /etc/init.d/riak start Riak failed to start within 15 seconds, see the output of 'riak console' for more information. If you want to wait longer, set the environment variable WAIT_FOR_ERLANG to the number of seconds to wait. I've tried to set WAIT_FOR_ERLANG value to 60 seconds but I can't. adding this line in vm.args didn't work: -env WAIT_FOR_ERLANG 60 I also tried to set this from terminal but it didn't work either. wolfiem@f01:~$ export WAIT_FOR_ERLANG=60 It still says "Riak failed to start within 15 seconds" This is the console.log output: 2012-09-11 10:58:02.532 [info] <0.7.0> Application lager started on node '[email protected]' 2012-09-11 10:58:02.560 [warning] <0.148.0>@riak_core_ring_manager:reload_ring:231 No ring file available. 2012-09-11 10:58:02.585 [error] <0.164.0> CRASH REPORT Process <0.164.0> with 0 neighbours exited with reason: eaddrnotavail in gen_server:init_it/6 line 320 This is the error.log output 2012-09-11 10:58:02.585 [error] <0.164.0> CRASH REPORT Process <0.164.0> with 0 neighbours exited with reason: eaddrnotavail in gen_server:init_it/6 line 320 This is the crash.log output: 2012-09-11 10:58:02 =CRASH REPORT==== crasher: initial call: mochiweb_socket_server:init/1 pid: <0.164.0> registered_name: [] exception exit: {eaddrnotavail,[{gen_server,init_it,6,[{file,"gen_server.erl"},{line,320}]},{proc_lib,init_p_do_apply,3,[{file,"proc_lib.erl"},{line,227}]}]} ancestors: [riak_core_sup,<0.135.0>] messages: [] links: [<0.136.0>] dictionary: [] trap_exit: true status: running heap_size: 377 stack_size: 24 reductions: 403 neighbours: You can find the riak console output below: wolfiem@f01:~$ riak console Attempting to restart script through sudo -H -u riak Exec: /usr/lib/riak/erts-5.9.1/bin/erlexec -boot /usr/lib/riak/releases/1.2.0/riak -embedded -config /etc/riak/app.config -pa /usr/lib/riak/basho-patches -args_file /etc/riak/vm.args -- console Root: /usr/lib/riak Erlang R15B01 (erts-5.9.1) [source] [64-bit] [smp:8:8] [async-threads:64] [kernel-poll:true] =INFO REPORT==== 11-Sep-2012::10:44:18 === alarm_handler: {set,{system_memory_high_watermark,[]}} ** /usr/lib/riak/lib/observer-1.1/ebin/etop_txt.beam hides /usr/lib/riak/lib/basho-patches/etop_txt.beam ** Found 1 name clashes in code paths 10:44:19.099 [info] Application lager started on node '[email protected]' 10:44:19.130 [warning] No ring file available. 10:44:19.158 [error] CRASH REPORT Process <0.164.0> with 0 neighbours exited with reason: eaddrnotavail in gen_server:init_it/6 line 320 /usr/lib/riak/lib/os_mon-2.2.9/priv/bin/memsup: Erlang has closed. =INFO REPORT==== 11-Sep-2012::10:44:19 === alarm_handler: {clear,system_memory_high_watermark} Erlang has closed {"Kernel pid terminated",application_controller,"{application_start_failure,riak_core,{shutdown,{riak_core_app,start,[normal,[]]}}}"} Crash dump was written to: /var/log/riak/erl_crash.dump Kernel pid terminated (application_controller) ({application_start_failure,riak_core,{shutdown,{riak_core_app,start,[normal,[]]}}})

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• How to resolve high CPU + excessive stat("/etc/localtime") and clock_gettime(CLOCK_REALTIME) calls

  - by Yemster

  I've been experiencing really high CPU on a ruby on rails app (see stack below) and have been trying to diagnose the possible causes to no avail. Stack: ruby 1.9.3 rails 3.2.6 Apache/2.2.21 (Debian) Phusion Passenger 3.0.11 Whenever I run strace against the spiking Rack process PID (see Top excerpt below), I am seeing a tonne of stat("/etc/localtime") and clock_gettime(CLOCK_REALTIME) calls and have no idea how to stop these. Excerpt from Top showin running PID: PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND 11674 www-user 20 0 313m 182m 5076 R 99 2.3 63:04.60 Rack: /var/www/my_rails_app/current 11634 www-user 20 0 411m 216m 5144 S 10 2.7 197:55.63 Rack: /var/www/my_rails_app/current Strace snippet below: [pid 11674] stat("/etc/localtime", {st_mode=S_IFREG|0644, st_size=118, ...}) = 0 [pid 11674] stat("/etc/localtime", {st_mode=S_IFREG|0644, st_size=118, ...}) = 0 [pid 11674] stat("/etc/localtime", {st_mode=S_IFREG|0644, st_size=118, ...}) = 0 [pid 11674] stat("/etc/localtime", {st_mode=S_IFREG|0644, st_size=118, ...}) = 0 [pid 11674] stat("/etc/localtime", {st_mode=S_IFREG|0644, st_size=118, ...}) = 0 [pid 11674] clock_gettime(CLOCK_REALTIME, {1354058955, 141474018}) = 0 [pid 11674] clock_gettime(CLOCK_REALTIME, {1354058955, 141577456}) = 0 [pid 11674] clock_gettime(CLOCK_REALTIME, {1354058955, 143073982}) = 0 [pid 11674] poll([{fd=15, events=POLLIN|POLLPRI}], 1, 0) = 0 (Timeout) [pid 11674] write(15, "b\0\0\0\3SELECT `images`.* FROM `ima"..., 102) = 102 [pid 11674] read(15, "\1\0\0\1\0229\0\0\2\3def\23myappy_productio"..., 16384) = 2063 [pid 11674] clock_gettime(CLOCK_REALTIME, {1354058955, 144138035}) = 0 [pid 11674] stat("/etc/localtime", {st_mode=S_IFREG|0644, st_size=118, ...}) = 0 [pid 11674] stat("/etc/localtime", {st_mode=S_IFREG|0644, st_size=118, ...}) = 0 [pid 11674] stat("/etc/localtime", {st_mode=S_IFREG|0644, st_size=118, ...}) = 0 [pid 11674] stat("/etc/localtime", {st_mode=S_IFREG|0644, st_size=118, ...}) = 0 ... [pid 11674] stat("/etc/localtime", {st_mode=S_IFREG|0644, st_size=118, ...}) = 0 [pid 11674] stat("/etc/localtime", {st_mode=S_IFREG|0644, st_size=118, ...}) = 0 [pid 11674] stat("/etc/localtime", {st_mode=S_IFREG|0644, st_size=118, ...}) = 0 [pid 11674] stat("/etc/localtime", {st_mode=S_IFREG|0644, st_size=118, ...}) = 0 [pid 11674] clock_gettime(CLOCK_REALTIME, {1354058955, 154076443}) = 0 [pid 11674] clock_gettime(CLOCK_REALTIME, {1354058955, 154189429}) = 0 [pid 11674] clock_gettime(CLOCK_REALTIME, {1354058955, 157185700}) = 0 [pid 11674] clock_gettime(CLOCK_REALTIME, {1354058955, 157298770}) = 0 [pid 11674] clock_gettime(CLOCK_REALTIME, {1354058955, 165076003}) = 0 [pid 11674] clock_gettime(CLOCK_REALTIME, {1354058955, 165212572}) = 0 [pid 11674] clock_gettime(CLOCK_REALTIME, {1354058955, 167542679}) = 0 [pid 11674] clock_gettime(CLOCK_REALTIME, {1354058955, 167683436}) = 0 .... [pid 11674] clock_gettime(CLOCK_REALTIME, {1354060036, 62052248}) = 0 [pid 11674] clock_gettime(CLOCK_REALTIME, {1354060036, 62182486}) = 0 [pid 11674] clock_gettime(CLOCK_REALTIME, {1354060036, 62919948}) = 0 [pid 11674] clock_gettime(CLOCK_REALTIME, {1354060036, 63057266}) = 0 [pid 11674] clock_gettime(CLOCK_REALTIME, {1354060036, 63751707}) = 0 [pid 11674] clock_gettime(CLOCK_REALTIME, {1354060036, 73730686}) = 0 [pid 11674] clock_gettime(CLOCK_REALTIME, {1354060036, 75874687}) = 0 [pid 11674] clock_gettime(CLOCK_REALTIME, {1354060036, 76077133}) = 0 [pid 11674] clock_gettime(CLOCK_REALTIME, {1354060036, 78205019}) = 0 ... [pid 11674] clock_gettime(CLOCK_REALTIME, {1354060036, 89370879}) = 0 [pid 11674] clock_gettime(CLOCK_REALTIME, {1354060036, 89583247}) = 0 [pid 11674] clock_gettime(CLOCK_REALTIME, {1354060036, 91637614}) = 0 [pid 11674] clock_gettime(CLOCK_REALTIME, {1354060036, 91782149}) = 0 Have Google'd around and came across a number of suggestions which I've tried with no success. Things tried so far: Have tried setting time zone as recommended here Made no difference and issue still persists. Content of my /etc/localtime: TZif2UTCTZif2UTC UTC0 Have tried the recommended fix for the leapsecond bug: date -s 'date' No joy so far. I'm fresh out of ideas so any help/advice on how to diagnose or resolve would be greatly appreciated.

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• Monitoring Html Element CSS Changes in JavaScript

  - by Rick Strahl

  [ updated Feb 15, 2011: Added event unbinding to avoid unintended recursion ] Here's a scenario I've run into on a few occasions: I need to be able to monitor certain CSS properties on an HTML element and know when that CSS element changes. For example, I have a some HTML element behavior plugins like a drop shadow that attaches to any HTML element, but I then need to be able to automatically keep the shadow in sync with the window if the  element dragged around the window or moved via code. Unfortunately there's no move event for HTML elements so you can't tell when it's location changes. So I've been looking around for some way to keep track of the element and a specific CSS property, but no luck. I suspect there's nothing native to do this so the only way I could think of is to use a timer and poll rather frequently for the property. I ended up with a generic jQuery plugin that looks like this: (function($){ $.fn.watch = function (props, func, interval, id) { /// <summary> /// Allows you to monitor changes in a specific /// CSS property of an element by polling the value. /// when the value changes a function is called. /// The function called is called in the context /// of the selected element (ie. this) /// </summary> /// <param name="prop" type="String">CSS Properties to watch sep. by commas</param> /// <param name="func" type="Function"> /// Function called when the value has changed. /// </param> /// <param name="interval" type="Number"> /// Optional interval for browsers that don't support DOMAttrModified or propertychange events. /// Determines the interval used for setInterval calls. /// </param> /// <param name="id" type="String">A unique ID that identifies this watch instance on this element</param> /// <returns type="jQuery" /> if (!interval) interval = 200; if (!id) id = "_watcher"; return this.each(function () { var _t = this; var el$ = $(this); var fnc = function () { __watcher.call(_t, id) }; var itId = null; var data = { id: id, props: props.split(","), func: func, vals: [props.split(",").length], fnc: fnc, origProps: props, interval: interval }; $.each(data.props, function (i) { data.vals[i] = el$.css(data.props[i]); }); el$.data(id, data); hookChange(el$, id, data.fnc); }); function hookChange(el$, id, fnc) { el$.each(function () { var el = $(this); if (typeof (el.get(0).onpropertychange) == "object") el.bind("propertychange." + id, fnc); else if ($.browser.mozilla) el.bind("DOMAttrModified." + id, fnc); else itId = setInterval(fnc, interval); }); } function __watcher(id) { var el$ = $(this); var w = el$.data(id); if (!w) return; var _t = this; if (!w.func) return; // must unbind or else unwanted recursion may occur el$.unwatch(id); var changed = false; var i = 0; for (i; i < w.props.length; i++) { var newVal = el$.css(w.props[i]); if (w.vals[i] != newVal) { w.vals[i] = newVal; changed = true; break; } } if (changed) w.func.call(_t, w, i); // rebind event hookChange(el$, id, w.fnc); } } $.fn.unwatch = function (id) { this.each(function () { var el = $(this); var fnc = el.data(id).fnc; try { if (typeof (this.onpropertychange) == "object") el.unbind("propertychange." + id, fnc); else if ($.browser.mozilla) el.unbind("DOMAttrModified." + id, fnc); else clearInterval(id); } // ignore if element was already unbound catch (e) { } }); return this; } })(jQuery); With this I can now monitor movement by monitoring say the top CSS property of the element. The following code creates a box and uses the draggable (jquery.ui) plugin and a couple of custom plugins that center and create a shadow. Here's how I can set this up with the watcher: $("#box") .draggable() .centerInClient() .shadow() .watch("top", function() { $(this).shadow(); },70,"_shadow"); ... $("#box") .unwatch("_shadow") .shadow("remove"); This code basically sets up the window to be draggable and initially centered and then a shadow is added. The .watch() call then assigns a CSS property to monitor (top in this case) and a function to call in response. The component now sets up a setInterval call and keeps on pinging this property every time. When the top value changes the supplied function is called. While this works and I can now drag my window around with the shadow following suit it's not perfect by a long shot. The shadow move is delayed and so drags behind the window, but using a higher timer value is not appropriate either as the UI starts getting jumpy if the timer's set with too small of an increment. This sort of monitor can be useful for other things as well where operations are maybe not quite as time critical as a UI operation taking place. Can anybody see a better a better way of capturing movement of an element on the page?© Rick Strahl, West Wind Technologies, 2005-2011Posted in ASP.NET  JavaScript  jQuery  

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• SQL Server Table Polling by Multiple Subscribers

  - by Daniel Hester

  Background Designing Stored Procedures that are safe for multiple subscribers (to call simultaneously) can be challenging.  For example let’s say that you want multiple worker processes to poll a shared work queue that’s encapsulated as a SQL Table. This is a common scenario and through experience you’ll find that you want to use Table Hints to prevent unwanted locking when performing simultaneous queries on the same table. There are three table hints to consider: NOLOCK, READPAST and UPDLOCK. Both NOLOCK and READPAST table hints allow you to SELECT from a table without placing a LOCK on that table. However, SELECTs with the READPAST hint will ignore any records that are locked due to being updated/inserted (or otherwise “dirty”), whereas a SELECT with NOLOCK ignores all locks including dirty reads. For the initial update of the flag (that marks the record as available for subscription) I don’t use the NOLOCK Table Hint because I want to be sensitive to the “active” records in the table and I want to exclude them.  I use an Update Lock (UPDLOCK) in conjunction with a WHERE clause that uses a sub-select with a READPAST Table Hint in order to explicitly lock the records I’m updating (UPDLOCK) but not place a lock on the table when selecting the records that I’m going to update (READPAST). UPDATES should be allowed to lock the rows affected because we’re probably changing a flag on a record so that it is not included in a SELECT from another subscriber. On the UPDATE statement we should explicitly use the UPDLOCK to guard against lock escalation. A SELECT to check for the next record(s) to process can result in a shared read lock being held by more than one subscriber polling the shared work queue (SQL table). It is expected that more than one worker process (or server) might try to process the same new record(s) at the same time. When each process then tries to obtain the update lock, none of them can because another process has a shared read lock in place. Thus without the UPDLOCK hint the result would be a lock escalation deadlock; however with the UPDLOCK hint this condition is mitigated against. Note that using the READPAST table hint requires that you also set the ISOLATION LEVEL of the transaction to be READ COMMITTED (rather than the default of SERIALIZABLE). Guidance In the Stored Procedure that returns records to the multiple subscribers: Perform the UPDATE first. Change the flag that makes the record available to subscribers.  Additionally, you may want to update a LastUpdated datetime field in order to be able to check for records that “got stuck” in an intermediate state or for other auditing purposes. In the UPDATE statement use the (UPDLOCK) Table Hint on the UPDATE statement to prevent lock escalation. In the UPDATE statement also use a WHERE Clause that uses a sub-select with a (READPAST) Table Hint to select the records that you’re going to update. In the UPDATE statement use the OUTPUT clause in conjunction with a Temporary Table to isolate the record(s) that you’ve just updated and intend to return to the subscriber. This is the fastest way to update the record(s) and to get the records’ identifiers within the same operation. Finally do a set-based SELECT on the main Table (using the Temporary Table to identify the records in the set) with either a READPAST or NOLOCK table hint.  Use NOLOCK if there are other processes (besides the multiple subscribers) that might be changing the data that you want to return to the multiple subscribers; or use READPAST if you're sure there are no other processes (besides the multiple subscribers) that might be updating column data in the table for other purposes (e.g. changes to a person’s last name).  NOLOCK is generally the better fit in this part of the scenario. See the following as an example: CREATE PROCEDURE [dbo].[usp_NewCustomersSelect] AS BEGIN -- OVERRIDE THE DEFAULT ISOLATION LEVEL SET TRANSACTION ISOLATION LEVEL READ COMMITTED -- SET NOCOUNT ON SET NOCOUNT ON -- DECLARE TEMP TABLE -- Note that this example uses CustomerId as an identifier; -- you could just use the Identity column Id if that’s all you need. DECLARE @CustomersTempTable TABLE ( CustomerId NVARCHAR(255) ) -- PERFORM UPDATE FIRST -- [Customers] is the name of the table -- [Id] is the Identity Column on the table -- [CustomerId] is the business document key used to identify the -- record globally, i.e. in other systems or across SQL tables -- [Status] is INT or BIT field (if the status is a binary state) -- [LastUpdated] is a datetime field used to record the time of the -- last update UPDATE [Customers] WITH (UPDLOCK) SET [Status] = 1, [LastUpdated] = GETDATE() OUTPUT [INSERTED].[CustomerId] INTO @CustomersTempTable WHERE ([Id] = (SELECT TOP 100 [Id] FROM [Customers] WITH (READPAST) WHERE ([Status] = 0) ORDER BY [Id] ASC)) -- PERFORM SELECT FROM ENTITY TABLE SELECT [C].[CustomerId], [C].[FirstName], [C].[LastName], [C].[Address1], [C].[Address2], [C].[City], [C].[State], [C].[Zip], [C].[ShippingMethod], [C].[Id] FROM [Customers] AS [C] WITH (NOLOCK), @CustomersTempTable AS [TEMP] WHERE ([C].[CustomerId] = [TEMP].[CustomerId]) END In a system that has been designed to have multiple status values for records that need to be processed in the Work Queue it is necessary to have a “Watch Dog” process by which “stale” records in intermediate states (such as “In Progress”) are detected, i.e. a [Status] of 0 = New or Unprocessed; a [Status] of 1 = In Progress; a [Status] of 2 = Processed; etc.. Thus, if you have a business rule that states that the application should only process new records if all of the old records have been processed successfully (or marked as an error), then it will be necessary to build a monitoring process to detect stalled or stale records in the Work Queue, hence the use of the LastUpdated column in the example above. The Status field along with the LastUpdated field can be used as the criteria to detect stalled / stale records. It is possible to put this watchdog logic into the stored procedure above, but I would recommend making it a separate monitoring function. In writing the stored procedure that checks for stale records I would recommend using the same kind of lock semantics as suggested above. The example below looks for records that have been in the “In Progress” state ([Status] = 1) for greater than 60 seconds: CREATE PROCEDURE [dbo].[usp_NewCustomersWatchDog] AS BEGIN -- TO OVERRIDE THE DEFAULT ISOLATION LEVEL SET TRANSACTION ISOLATION LEVEL READ COMMITTED -- SET NOCOUNT ON SET NOCOUNT ON DECLARE @MaxWait int; SET @MaxWait = 60 IF EXISTS (SELECT 1 FROM [dbo].[Customers] WITH (READPAST) WHERE ([Status] = 1) AND (DATEDIFF(s, [LastUpdated], GETDATE()) > @MaxWait)) BEGIN SELECT 1 AS [IsWatchDogError] END ELSE BEGIN SELECT 0 AS [IsWatchDogError] END END Downloads The zip file below contains two SQL scripts: one to create a sample database with the above stored procedures and one to populate the sample database with 10,000 sample records.  I am very grateful to Red-Gate software for their excellent SQL Data Generator tool which enabled me to create these sample records in no time at all. References http://msdn.microsoft.com/en-us/library/ms187373.aspx http://www.techrepublic.com/article/using-nolock-and-readpast-table-hints-in-sql-server/6185492 http://geekswithblogs.net/gwiele/archive/2004/11/25/15974.aspx http://grounding.co.za/blogs/romiko/archive/2009/03/09/biztalk-sql-receive-location-deadlocks-dirty-reads-and-isolation-levels.aspx

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• Nvidia drivers don't work with mainline kernel

  - by dutchie

  I want to try some of the new features in the btrfs filesystem, and to do that I need to use a newer kernel than is included in Ubuntu 12.04. To do that, I have installed linux-headers-3.4.0-030400_3.4.0-030400.201205210521_all.deb, linux-headers-3.4.0-030400-generic_3.4.0-030400.201205210521_amd64.deb, and linux-image-3.4.0-030400-generic_3.4.0-030400.201205210521_amd64.deb from the mainline kernel download here. However, on rebooting into the 3.4 kernel, my desktop is stuck at a very low resolution and I cannot increase it to the full. This did happen when I first installed, but a simple install of the nvidia-current package got everything working nicely with my GTX570 card. There were appear to be some DKMS errors when I installed the kernel, and they indicated I should look at /var/lib/dkms/nvidia-current/295.40/build/make.log: josh@sirius:~/Downloads$ sudo dpkg -i linux-*.deb Selecting previously unselected package linux-headers-3.4.0-030400. (Reading database ... 309400 files and directories currently installed.) Unpacking linux-headers-3.4.0-030400 (from linux-headers-3.4.0-030400_3.4.0-030400.201205210521_all.deb) ... Selecting previously unselected package linux-headers-3.4.0-030400-generic. Unpacking linux-headers-3.4.0-030400-generic (from linux-headers-3.4.0-030400-generic_3.4.0-030400.201205210521_amd64.deb) ... Selecting previously unselected package linux-image-3.4.0-030400-generic. Unpacking linux-image-3.4.0-030400-generic (from linux-image-3.4.0-030400-generic_3.4.0-030400.201205210521_amd64.deb) ... Done. Setting up linux-headers-3.4.0-030400 (3.4.0-030400.201205210521) ... Setting up linux-headers-3.4.0-030400-generic (3.4.0-030400.201205210521) ... Examining /etc/kernel/header_postinst.d. run-parts: executing /etc/kernel/header_postinst.d/dkms 3.4.0-030400-generic /boot/vmlinuz-3.4.0-030400-generic ERROR (dkms apport): kernel package linux-headers-3.4.0-030400-generic is not supported Error! Bad return status for module build on kernel: 3.4.0-030400-generic (x86_64) Consult /var/lib/dkms/nvidia-current/295.40/build/make.log for more information. Setting up linux-image-3.4.0-030400-generic (3.4.0-030400.201205210521) ... Running depmod. update-initramfs: deferring update (hook will be called later) Examining /etc/kernel/postinst.d. run-parts: executing /etc/kernel/postinst.d/dkms 3.4.0-030400-generic /boot/vmlinuz-3.4.0-030400-generic ERROR (dkms apport): kernel package linux-headers-3.4.0-030400-generic is not supported Error! Bad return status for module build on kernel: 3.4.0-030400-generic (x86_64) Consult /var/lib/dkms/nvidia-current/295.40/build/make.log for more information. run-parts: executing /etc/kernel/postinst.d/initramfs-tools 3.4.0-030400-generic /boot/vmlinuz-3.4.0-030400-generic update-initramfs: Generating /boot/initrd.img-3.4.0-030400-generic run-parts: executing /etc/kernel/postinst.d/pm-utils 3.4.0-030400-generic /boot/vmlinuz-3.4.0-030400-generic run-parts: executing /etc/kernel/postinst.d/update-notifier 3.4.0-030400-generic /boot/vmlinuz-3.4.0-030400-generic run-parts: executing /etc/kernel/postinst.d/zz-update-grub 3.4.0-030400-generic /boot/vmlinuz-3.4.0-030400-generic Generating grub.cfg ... Found linux image: /boot/vmlinuz-3.4.0-030400-generic Found initrd image: /boot/initrd.img-3.4.0-030400-generic Found linux image: /boot/vmlinuz-3.2.0-24-generic Found initrd image: /boot/initrd.img-3.2.0-24-generic Found memtest86+ image: /memtest86+.bin Found Ubuntu 12.04 LTS (12.04) on /dev/sda1 Found Windows 7 (loader) on /dev/sda2 Found Windows 7 (loader) on /dev/sda3 done /var/lib/dkms/nvidia-current/295.40/build/make.log: DKMS make.log for nvidia-current-295.40 for kernel 3.4.0-030400-generic (x86_64) Thu Jun 7 00:58:39 BST 2012 NVIDIA: calling KBUILD... test -e include/generated/autoconf.h -a -e include/config/auto.conf || ( \ echo; \ echo " ERROR: Kernel configuration is invalid."; \ echo " include/generated/autoconf.h or include/config/auto.conf are missing.";\ echo " Run 'make oldconfig && make prepare' on kernel src to fix it."; \ echo; \ /bin/false) mkdir -p /var/lib/dkms/nvidia-current/295.40/build/.tmp_versions ; rm -f /var/lib/dkms/nvidia-current/295.40/build/.tmp_versions/* make -f scripts/Makefile.build obj=/var/lib/dkms/nvidia-current/295.40/build cc -Wp,-MD,/var/lib/dkms/nvidia-current/295.40/build/.nv.o.d -nostdinc -isystem /usr/lib/gcc/x86_64-linux-gnu/4.6/include -I/usr/src/linux-headers-3.4.0-030400-generic/arch/x86/include -Iarch/x86/include/generated -Iinclude -include /usr/src/linux-headers-3.4.0-030400-generic/include/linux/kconfig.h -D__KERNEL__ -Wall -Wundef -Wstrict-prototypes -Wno-trigraphs -fno-strict-aliasing -fno-common -Werror-implicit-function-declaration -Wno-format-security -fno-delete-null-pointer-checks -O2 -m64 -mtune=generic -mno-red-zone -mcmodel=kernel -funit-at-a-time -maccumulate-outgoing-args -fstack-protector -DCONFIG_AS_CFI=1 -DCONFIG_AS_CFI_SIGNAL_FRAME=1 -DCONFIG_AS_CFI_SECTIONS=1 -DCONFIG_AS_FXSAVEQ=1 -pipe -Wno-sign-compare -fno-asynchronous-unwind-tables -mno-sse -mno-mmx -mno-sse2 -mno-3dnow -mno-avx -Wframe-larger-than=1024 -Wno-unused-but-set-variable -fno-omit-frame-pointer -fno-optimize-sibling-calls -pg -Wdeclaration-after-statement -Wno-pointer-sign -fno-strict-overflow -fconserve-stack -DCC_HAVE_ASM_GOTO -I/var/lib/dkms/nvidia-current/295.40/build -Wall -MD -Wsign-compare -Wno-cast-qual -Wno-error -D__KERNEL__ -DMODULE -DNVRM -DNV_VERSION_STRING=\"295.40\" -Wno-unused-function -Wuninitialized -mno-red-zone -mcmodel=kernel -UDEBUG -U_DEBUG -DNDEBUG -DMODULE -D"KBUILD_STR(s)=#s" -D"KBUILD_BASENAME=KBUILD_STR(nv)" -D"KBUILD_MODNAME=KBUILD_STR(nvidia)" -c -o /var/lib/dkms/nvidia-current/295.40/build/.tmp_nv.o /var/lib/dkms/nvidia-current/295.40/build/nv.c In file included from include/linux/kernel.h:19:0, from include/linux/sched.h:55, from include/linux/utsname.h:35, from /var/lib/dkms/nvidia-current/295.40/build/nv-linux.h:38, from /var/lib/dkms/nvidia-current/295.40/build/nv.c:13: include/linux/bitops.h: In function ‘hweight_long’: include/linux/bitops.h:66:41: warning: signed and unsigned type in conditional expression [-Wsign-compare] In file included from /usr/src/linux-headers-3.4.0-030400-generic/arch/x86/include/asm/uaccess.h:577:0, from include/linux/poll.h:14, from /var/lib/dkms/nvidia-current/295.40/build/nv-linux.h:97, from /var/lib/dkms/nvidia-current/295.40/build/nv.c:13: /usr/src/linux-headers-3.4.0-030400-generic/arch/x86/include/asm/uaccess_64.h: In function ‘copy_from_user’: /usr/src/linux-headers-3.4.0-030400-generic/arch/x86/include/asm/uaccess_64.h:53:6: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] In file included from /var/lib/dkms/nvidia-current/295.40/build/nv.c:13:0: /var/lib/dkms/nvidia-current/295.40/build/nv-linux.h: At top level: /var/lib/dkms/nvidia-current/295.40/build/nv-linux.h:114:75: fatal error: asm/system.h: No such file or directory compilation terminated. make[3]: *** [/var/lib/dkms/nvidia-current/295.40/build/nv.o] Error 1 make[2]: *** [_module_/var/lib/dkms/nvidia-current/295.40/build] Error 2 NVIDIA: left KBUILD. nvidia.ko failed to build! make[1]: *** [module] Error 1 make: *** [module] Error 2

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• SOA Suite Integration: Part 3: Loading files

  - by Anthony Shorten

  One of the most common scenarios in SOA Integration is the loading of a file into the product from an external source. In Oracle SOA Suite there is a File Adapter that can process many file types into your BPEL process. For this example I will use the File Adapter to load a file of user and emails to update the user object within the Oracle Utilities Application Framework. Remember you can repeat this process with other objects and other file types. Again I am illustrating the ease of integration. The first thing is to create an empty BPEL process that will hold our flow. In Oracle JDeveloper this can be achieved by specifying the Define Service Later template (as other templates have predefined inputs and outputs and in this case we want to specify those). So I will create simpleFileLoad process to house our process. You will start with an empty canvas so you need to first specify the load part of the process using the File Adapter. Select the File Adapter from the Component Palette under BPEL Services and drag and drop it to the left side Partner Links (left is input). You name the Service. In this case I chose LoadFile. Press Next. We will define the interface as part of the wizard so select Define from operation and schema (specified later). Press Next. We are going to choose Read File to denote that we will read the file and specify the default Operation Name as Read. Press Next. The next step is to tell the Adapter the location of the files, how to process them and what to do with them after they have been processed. I am using hardcoded locations in this example but you can have logical locations as well. Press Next. I am now going to tell the adapter how to recognize the files I want to load. In my case I am using CSV files and more importantly I am tell the adapter to run the process for each record in the file it encounters. Press Next. Now, I tell the adapter how often I want to poll for the files. I have taken the defaults. Press Next. At this stage I have no explanation of the format of the input. So I am going to invoke the Native Format Wizard which will guide me through the process of creating the file input format. Clicking the purple cog icon will start the wizard. After an introduction screen (not shown), you specify the format of the input file. The File Adapter supports multiple format types. For this example, I will use Delimited as I am going to load a CSV file. Press Next. The best way for the wizard to work is with a sample. I have a sample file and the wizard will ask how much of the file to use as a template. I will use the defaults. Note: If you are using a language that has other languages other than US-ASCII, it is at this point you specify the character set to use.  Press Next. The sample contains multiple instances of a single record type. The wizard supports complex types as well. We will use the appropriate setting for our file. Press Next. You have to specify the file element and the record element. This will be used by the input wizard to translate the CSV data into an XML structure (this will make sense later). I am using LoadUsers as my file delimiter (root element) and User Record as my record root element. Press Next. As the file is CSV the delimiter is "," so I will also specify that the End Of Line (EOL) indicator indicates the end of a record. Press Next. Up until this point your have not given the columns their names. In my case my sample includes the column names in the first record. This is not always the case but you can specify the names and formats of columns in this dialog (not shown). Press Next. The wizard now generates the schema for the input file. You can specify a name for the schema. I have used userupdate.xsd. We want to verify the schema so press Test. You can test the schema by specifying an input sample. and pressing the green play button. You will see the delimiters you specified earlier for the file and the records. Press Ok to continue. A confirmation screen will be displayed showing you the location of the schema in your project. Press Finish to return to the File Adapter configuration. You will now see the schema and elements prepopulated from the wizard. Press Next. The File Adapter configuration is now complete. Press Finish. Now you need to receive the input from the LoadFile component so we need to place a Receive node in the BPEL process by drag and dropping the Receive component from the Component Palette under BPEL Constructs onto the BPEL process. We link the receive process with the LoadFile component by dragging the left most connect node of the Receive node to the LoadFile component. Once the link is established you need to name the Receive node appropriately and as in the post of the last part of this series you need to generate input variables for the BPEL process to hold the input records in. You need to now add the product Web Service. The process is the same as described in the post of the last part of this series. You drop the Web Service BPEL Service onto the right side of the process and fill in the details of the WSDL URL . You also have to add an Invoke node to call the service and generate the input and outputs variables for the call in the Invoke node. Now, to get the inputs from File to the service. You have to use a Transform (you can use an Assign action but a Transform action is more flexible). You drag and drop the Transform component from the Component Palette under Oracle Extensions and place it between the Receive and Invoke nodes. We name the Transform Node, Mapper File and associate the source of the mapping the schema from the Receive node and the output will be the input variable from the Invoke node. We now build the transform. We first map the user and email attributes by drag and drop the elements from the left to the right. The reason we needed to use the transform is that we will be telling the AS-User service that we want to issue an update action. Remember when we registered the service we actually used Read as the default. If we do not otherwise inform the service to use the Update action it will use the Read action instead (which is not desired). To specify the update action you need to click on the transactionType node on the right and select Set Text to set the action. You need to specify the transactionType of UPD (for update). The mapping is now complete. The final BPEL process is ready for deployment. You then deploy the BPEL process to the server and to test the service by simply dropping a file, in the same pattern/name as you specified, in the directory you specified in the File Adapter. You will see each record as a separate instance entry in the Fusion Middleware Control console. You can now load files into the product. You can repeat this process for each type of file to process. While this was a simple example it illustrates the method of loading data can be achieved using SOA Suite in conjunction with our products.

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• Parallelism in .NET – Part 3, Imperative Data Parallelism: Early Termination

  - by Reed

  Although simple data parallelism allows us to easily parallelize many of our iteration statements, there are cases that it does not handle well.  In my previous discussion, I focused on data parallelism with no shared state, and where every element is being processed exactly the same. Unfortunately, there are many common cases where this does not happen.  If we are dealing with a loop that requires early termination, extra care is required when parallelizing. Often, while processing in a loop, once a certain condition is met, it is no longer necessary to continue processing.  This may be a matter of finding a specific element within the collection, or reaching some error case.  The important distinction here is that, it is often impossible to know until runtime, what set of elements needs to be processed. In my initial discussion of data parallelism, I mentioned that this technique is a candidate when you can decompose the problem based on the data involved, and you wish to apply a single operation concurrently on all of the elements of a collection.  This covers many of the potential cases, but sometimes, after processing some of the elements, we need to stop processing. As an example, lets go back to our previous Parallel.ForEach example with contacting a customer.  However, this time, we’ll change the requirements slightly.  In this case, we’ll add an extra condition – if the store is unable to email the customer, we will exit gracefully.  The thinking here, of course, is that if the store is currently unable to email, the next time this operation runs, it will handle the same situation, so we can just skip our processing entirely.  The original, serial case, with this extra condition, might look something like the following: foreach(var customer in customers) { // Run some process that takes some time... DateTime lastContact = theStore.GetLastContact(customer); TimeSpan timeSinceContact = DateTime.Now - lastContact; // If it's been more than two weeks, send an email, and update... if (timeSinceContact.Days > 14) { // Exit gracefully if we fail to email, since this // entire process can be repeated later without issue. if (theStore.EmailCustomer(customer) == false) break; customer.LastEmailContact = DateTime.Now; } } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } Here, we’re processing our loop, but at any point, if we fail to send our email successfully, we just abandon this process, and assume that it will get handled correctly the next time our routine is run.  If we try to parallelize this using Parallel.ForEach, as we did previously, we’ll run into an error almost immediately: the break statement we’re using is only valid when enclosed within an iteration statement, such as foreach.  When we switch to Parallel.ForEach, we’re no longer within an iteration statement – we’re a delegate running in a method. This needs to be handled slightly differently when parallelized.  Instead of using the break statement, we need to utilize a new class in the Task Parallel Library: ParallelLoopState.  The ParallelLoopState class is intended to allow concurrently running loop bodies a way to interact with each other, and provides us with a way to break out of a loop.  In order to use this, we will use a different overload of Parallel.ForEach which takes an IEnumerable<T> and an Action<T, ParallelLoopState> instead of an Action<T>.  Using this, we can parallelize the above operation by doing: Parallel.ForEach(customers, (customer, parallelLoopState) => { // Run some process that takes some time... DateTime lastContact = theStore.GetLastContact(customer); TimeSpan timeSinceContact = DateTime.Now - lastContact; // If it's been more than two weeks, send an email, and update... if (timeSinceContact.Days > 14) { // Exit gracefully if we fail to email, since this // entire process can be repeated later without issue. if (theStore.EmailCustomer(customer) == false) parallelLoopState.Break(); else customer.LastEmailContact = DateTime.Now; } }); There are a couple of important points here.  First, we didn’t actually instantiate the ParallelLoopState instance.  It was provided directly to us via the Parallel class.  All we needed to do was change our lambda expression to reflect that we want to use the loop state, and the Parallel class creates an instance for our use.  We also needed to change our logic slightly when we call Break().  Since Break() doesn’t stop the program flow within our block, we needed to add an else case to only set the property in customer when we succeeded.  This same technique can be used to break out of a Parallel.For loop. That being said, there is a huge difference between using ParallelLoopState to cause early termination and to use break in a standard iteration statement.  When dealing with a loop serially, break will immediately terminate the processing within the closest enclosing loop statement.  Calling ParallelLoopState.Break(), however, has a very different behavior. The issue is that, now, we’re no longer processing one element at a time.  If we break in one of our threads, there are other threads that will likely still be executing.  This leads to an important observation about termination of parallel code: Early termination in parallel routines is not immediate.  Code will continue to run after you request a termination. This may seem problematic at first, but it is something you just need to keep in mind while designing your routine.  ParallelLoopState.Break() should be thought of as a request.  We are telling the runtime that no elements that were in the collection past the element we’re currently processing need to be processed, and leaving it up to the runtime to decide how to handle this as gracefully as possible.  Although this may seem problematic at first, it is a good thing.  If the runtime tried to immediately stop processing, many of our elements would be partially processed.  It would be like putting a return statement in a random location throughout our loop body – which could have horrific consequences to our code’s maintainability. In order to understand and effectively write parallel routines, we, as developers, need a subtle, but profound shift in our thinking.  We can no longer think in terms of sequential processes, but rather need to think in terms of requests to the system that may be handled differently than we’d first expect.  This is more natural to developers who have dealt with asynchronous models previously, but is an important distinction when moving to concurrent programming models. As an example, I’ll discuss the Break() method.  ParallelLoopState.Break() functions in a way that may be unexpected at first.  When you call Break() from a loop body, the runtime will continue to process all elements of the collection that were found prior to the element that was being processed when the Break() method was called.  This is done to keep the behavior of the Break() method as close to the behavior of the break statement as possible. We can see the behavior in this simple code: var collection = Enumerable.Range(0, 20); var pResult = Parallel.ForEach(collection, (element, state) => { if (element > 10) { Console.WriteLine("Breaking on {0}", element); state.Break(); } Console.WriteLine(element); }); If we run this, we get a result that may seem unexpected at first: 0 2 1 5 6 3 4 10 Breaking on 11 11 Breaking on 12 12 9 Breaking on 13 13 7 8 Breaking on 15 15 What is occurring here is that we loop until we find the first element where the element is greater than 10.  In this case, this was found, the first time, when one of our threads reached element 11.  It requested that the loop stop by calling Break() at this point.  However, the loop continued processing until all of the elements less than 11 were completed, then terminated.  This means that it will guarantee that elements 9, 7, and 8 are completed before it stops processing.  You can see our other threads that were running each tried to break as well, but since Break() was called on the element with a value of 11, it decides which elements (0-10) must be processed. If this behavior is not desirable, there is another option.  Instead of calling ParallelLoopState.Break(), you can call ParallelLoopState.Stop().  The Stop() method requests that the runtime terminate as soon as possible , without guaranteeing that any other elements are processed.  Stop() will not stop the processing within an element, so elements already being processed will continue to be processed.  It will prevent new elements, even ones found earlier in the collection, from being processed.  Also, when Stop() is called, the ParallelLoopState’s IsStopped property will return true.  This lets longer running processes poll for this value, and return after performing any necessary cleanup. The basic rule of thumb for choosing between Break() and Stop() is the following. Use ParallelLoopState.Stop() when possible, since it terminates more quickly.  This is particularly useful in situations where you are searching for an element or a condition in the collection.  Once you’ve found it, you do not need to do any other processing, so Stop() is more appropriate. Use ParallelLoopState.Break() if you need to more closely match the behavior of the C# break statement. Both methods behave differently than our C# break statement.  Unfortunately, when parallelizing a routine, more thought and care needs to be put into every aspect of your routine than you may otherwise expect.  This is due to my second observation: Parallelizing a routine will almost always change its behavior. This sounds crazy at first, but it’s a concept that’s so simple its easy to forget.  We’re purposely telling the system to process more than one thing at the same time, which means that the sequence in which things get processed is no longer deterministic.  It is easy to change the behavior of your routine in very subtle ways by introducing parallelism.  Often, the changes are not avoidable, even if they don’t have any adverse side effects.  This leads to my final observation for this post: Parallelization is something that should be handled with care and forethought, added by design, and not just introduced casually.

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