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  • Slow Windows Explorer on Windows 7

    - by MadBoy
    I have Laptop with i7 (4 cores), 8GB ram and SSD OCZ Vertex 3 MaxIOPS which in testing that I did just now does 400mb/s+ read/write. However the responsiveness of Windows Explorer is far from being perfect. Opening up Computer, Documents, going into folders is very slow (1-5seconds). I don't have any viruses or spyware and I have tried changing properties to optimize view for General Items. I tried disabling Search Indexer but it made search in Outlook 2010 crawl and didn't bring any other effect. Even double clicking on file takes some time to open things up (like clicking a Word document). I don't have any drives mapped, my computer is not joined to domain. I have multiple VPN connections that I connect to but they all have disabled default gateways. I tried using CC Cleaner or some Windows 7 Tweaks app to disable some things. I am power user using Visual Studio, Tortoise SVN and other developer/administration apps. Any non obvious ideas? Edit: So I've been trying to pinpoint where the issue comes from and it seems that straight after reboot Windows Explorer opens very fast, when I load 3-4 programs (Royal TS, Visual Studio, Outlook) it's noticeably slower and the more programs I have it gets worse. After I start closing programs it starts working better and if I leave 2 open it's fast again. I tried doing some research with DiskMon and other programs from sysinternals but couldn't find anything suspicious. Below are stats during normal usage with a lots of programs open: - Ram usage with a lot of programs open and no swap file (i disabled it for testing): 6.95GB - CPU usage: 15%, none of the cores takes more then 50% (I have VS 2010 open x 4) HD Tune Pro: OCZ-VERTEX3 MI Benchmark Test capacity: full Read transfer rate Transfer Rate Minimum : 363.9 MB/s Transfer Rate Maximum : 505.5 MB/s Transfer Rate Average : Access Time : Burst Rate : CPU Usage : HD Tune Pro: OCZ-VERTEX3 MI File Benchmark Drive C: Transfer rate test File Size: 500 MB Sequential read 484102 KB/s Sequential write 444714 KB/s Random read 7779 IOPS Random write 16888 IOPS Random read (queue depth = 32) 73007 IOPS Random write (queue depth = 32) 69790 IOPS HD Tune Pro: OCZ-VERTEX3 MI Random Access Test capacity: full Read test Transfer size operations / sec avg. access time max. access time avg. speed 512 bytes 3260 IOPS 0.306 ms 2.106 ms 1.592 MB/s 4 KB 4161 IOPS 0.240 ms 2.006 ms 16.256 MB/s 64 KB 2382 IOPS 0.419 ms 2.367 ms 148.934 MB/s 1 MB 449 IOPS 2.225 ms 4.197 ms 449.407 MB/s Random 809 IOPS 1.235 ms 6.551 ms 410.527 MB/s HD Tune Pro: OCZ-VERTEX3 MI Extra Tests Test capacity: full Random seek 3975 IOPS 0.252 ms 1.941 MB/s Random seek 4 KB 4245 IOPS 0.236 ms 16.583 MB/s Butterfly seek 4086 IOPS 0.245 ms 1.995 MB/s Random seek / size 64 KB 3812 IOPS 0.262 ms 58.606 MB/s Random seek / size 8 MB 120 IOPS 8.348 ms 485.737 MB/s Sequential outer 4524 IOPS 0.221 ms 282.721 MB/s Sequential middle 4429 IOPS 0.226 ms 276.818 MB/s Sequential inner 5504 IOPS 0.182 ms 344.000 MB/s Burst rate 4472 IOPS 0.224 ms 279.475 MB/s

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  • Preventing Postfix backscattering

    - by Must Do Better
    I am having problems with the Postfix mail server being used for backscattering, I have tried the suggestions in the manual but nothing seems to work. Does anyone know how we can reject any mail from entering the queue if the recipient doesn't match a local recipient rather than send bounce emails? I'm assuming it should be a fairly straight forward change in the configuration files. Just to note I am using Webmin/Virtualmin on the server.

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  • Exception while running Quartz Schdular program

    - by Sunny Mate
    hi, i am getting he following Exception while running my Quartz Schdular program. Below is the exception Trace Mar 26, 2010 2:54:24 PM org.quartz.core.QuartzScheduler start INFO: Scheduler DefaultQuartzScheduler_$_NON_CLUSTERED started. Exception in thread "main" java.lang.IllegalArgumentException: Job class must implement the Job interface. at org.quartz.JobDetail.setJobClass(JobDetail.java:291) at org.quartz.JobDetail.(JobDetail.java:138) at com.Quarrtz.RanchSchedule.main(RanchSchedule.java:18) i have included Quartz-1.7.2.jar and Quartz-all-1.7.2.jar in my class path along with commom-logging 1.1.jar and jdk 6 this is an example i have copy and pasted from JAVA RANCH http://www.javaranch.com/journal/200711/combining_spring_and_quartz.html First example in the above page any help pls thanx in advance Sunny Mate

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  • What happens when a server has too many requests?

    - by eSKay
    I am wondering why websites crash at all. If a server has too many requests, it might queue up the request in its waiting lists and serve it when all the earlier requests have been served. That means that the request for the website will be taken care of, although it may take some more time than expected. Then, how do websites crash due to server overload?

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  • Cron syntax with Java EE 5?

    - by marabol
    Timer Tasks in Java EE are not very comfortable. Is there any util, to configure timer with cron syntax like "0 20 20 * * "? I wonder, if it would be a good way to use Quartzinside (clustered) JEE application. According to http://www.prozesse-und-systeme.de/serverClustering.html (german page) there limits with Quartz and Java EE clustering: JDBC must be used as job store for Quartz Only cluster associated Quartz instances are allowed to use this JDBC job store All cluster nodes must be synchronized to the split second All cluster nodes must use the same quartz.properties file I would prefer an easier way for configuration of timer service, instead an not Java EE managed scheduler.

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  • How does too many requests make a server crash?

    - by eSKay
    I am wondering why websites crash at all. If a server has too many requests, it might queue up the request in its waiting lists and serve it when all the earlier requests have been served. That means that the request for the website will be taken care of, although it may take some more time than expected. Then, how do websites crash due to server overload?

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  • Investigate high load on RHEL

    - by Adam Matan
    One of my RHEL 5 was showing high load (~4-5) on uptime. The load increased, and when it reached 6 (±), the server froze and needed restart. top-wise, the server had no significant CPU or memory issues and sar showed no increase in iowait. Therefore, the thrashing must have been related to other factors. Any ideas how to investigate this? In particular, how do I know that which processes are waiting in the queue?

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  • How to disable Events for a while in Javascript or jQuery

    - by Tarik
    Hello, I am wondering if you guys know different approach to disable an event for a while. Let me elaborate this more : Lets say I have a div or button which has a subscriber to its onclick event. To prevent the double click when the the methods are doing some ajax things, these are the some of the ways we can do : Disable the button till the method finishes its job Unbind till the methods finishes its job and then bind it again. Use some kind of flagging system like boolean so it will prevent method from working more than once. So is there any other ways, maybe some javascript tricks or jQuery tricks which is more efficient and better practice. Thanks in advance.

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  • How to download images in playframework jobs?

    - by MrROY
    I have a playframework Job class like this: public class ImageDownloader extends Job { private String[] urls; private String dir; public ImageDownloader(){} public ImageDownloader(String[] urls,String dir){ this.urls = urls; this.dir = dir; } @Override public void doJob() throws Exception { if(urls!=null && urls.length > 0){ for (int i = 0; i < urls.length; i++) { String url = urls[i]; //Dowloading } } } } Play(1.2.4) has lots of amazing tools to make things easy. So i wonder whether there's a way to make the downloading easy and beautiful in play ?

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  • Streaming Netflix through Wifi kills all other devices

    - by maleki
    I have a "Belkin N150" Router. My current setup is wired connection to my personal tv and xbox with wireless going to the Wii and Bedroom laptop. Anytime I try streaming Netflix Instant Queue on the Wii, every other device has problems. The Wii works fine but everything else's connection is destroyed. Streaming through the Xbox doesn't create any issues for other devices. What kind of issue is occurring and how can I fix it?

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  • How does too many requests make a server crash?

    - by eSKay
    I am wondering why websites crash at all. If a server has too many requests, it might queue up the request in its waiting lists and serve it when all the earlier requests have been served. That means that the request for the website will be taken care of, although it may take some more time than expected. Then, how do websites crash due to server overload?

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  • Query on simple C++ threadpool implementation

    - by ticketman
    Stackoverflow has been a tremendous help to me and I'd to give something back to the community. I have been implementing a simple threadpool using the tinythread C++ portable thread library, using what I have learnt from Stackoverflow. I am new to thread programming, so not that comfortable with mutexes, etc. I have a question best asked after presenting the code (which runs quite well under Linux): // ThreadPool.h class ThreadPool { public: ThreadPool(); ~ThreadPool(); // Creates a pool of threads and gets them ready to be used void CreateThreads(int numOfThreads); // Assigns a job to a thread in the pool, but doesn't start the job // Each SubmitJob call will use up one thread of the pool. // This operation can only be undone by calling StartJobs and // then waiting for the jobs to complete. On completion, // new jobs may be submitted. void SubmitJob( void (*workFunc)(void *), void *workData ); // Begins execution of all the jobs in the pool. void StartJobs(); // Waits until all jobs have completed. // The wait will block the caller. // On completion, new jobs may be submitted. void WaitForJobsToComplete(); private: enum typeOfWorkEnum { e_work, e_quit }; class ThreadData { public: bool ready; // thread has been created and is ready for work bool haveWorkToDo; typeOfWorkEnum typeOfWork; // Pointer to the work function each thread has to call. void (*workFunc)(void *); // Pointer to work data void *workData; ThreadData() : ready(false), haveWorkToDo(false) { }; }; struct ThreadArgStruct { ThreadPool *threadPoolInstance; int threadId; }; // Data for each thread ThreadData *m_ThreadData; ThreadPool(ThreadPool const&); // copy ctor hidden ThreadPool& operator=(ThreadPool const&); // assign op. hidden // Static function that provides the function pointer that a thread can call // By including the ThreadPool instance in the void * parameter, // we can use it to access other data and methods in the ThreadPool instance. static void ThreadFuncWrapper(void *arg) { ThreadArgStruct *threadArg = static_cast<ThreadArgStruct *>(arg); threadArg->threadPoolInstance->ThreadFunc(threadArg->threadId); } // The function each thread calls void ThreadFunc( int threadId ); // Called by the thread pool destructor void DestroyThreadPool(); // Total number of threads available // (fixed on creation of thread pool) int m_numOfThreads; int m_NumOfThreadsDoingWork; int m_NumOfThreadsGivenJobs; // List of threads std::vector<tthread::thread *> m_ThreadList; // Condition variable to signal each thread has been created and executing tthread::mutex m_ThreadReady_mutex; tthread::condition_variable m_ThreadReady_condvar; // Condition variable to signal each thread to start work tthread::mutex m_WorkToDo_mutex; tthread::condition_variable m_WorkToDo_condvar; // Condition variable to signal the main thread that // all threads in the pool have completed their work tthread::mutex m_WorkCompleted_mutex; tthread::condition_variable m_WorkCompleted_condvar; }; cpp file: // // ThreadPool.cpp // #include "ThreadPool.h" // This is the thread function for each thread. // All threads remain in this function until // they are asked to quit, which only happens // when terminating the thread pool. void ThreadPool::ThreadFunc( int threadId ) { ThreadData *myThreadData = &m_ThreadData[threadId]; std::cout << "Hello world: Thread " << threadId << std::endl; // Signal that this thread is ready m_ThreadReady_mutex.lock(); myThreadData->ready = true; m_ThreadReady_condvar.notify_one(); // notify the main thread m_ThreadReady_mutex.unlock(); while(true) { //tthread::lock_guard<tthread::mutex> guard(m); m_WorkToDo_mutex.lock(); while(!myThreadData->haveWorkToDo) // check for work to do m_WorkToDo_condvar.wait(m_WorkToDo_mutex); // if no work, wait here myThreadData->haveWorkToDo = false; // need to do this before unlocking the mutex m_WorkToDo_mutex.unlock(); // Do the work switch(myThreadData->typeOfWork) { case e_work: std::cout << "Thread " << threadId << ": Woken with work to do\n"; // Do work myThreadData->workFunc(myThreadData->workData); std::cout << "#Thread " << threadId << ": Work is completed\n"; break; case e_quit: std::cout << "Thread " << threadId << ": Asked to quit\n"; return; // ends the thread } // Now to signal the main thread that my work is completed m_WorkCompleted_mutex.lock(); m_NumOfThreadsDoingWork--; // Unsure if this 'if' would make the program more efficient // if(NumOfThreadsDoingWork == 0) m_WorkCompleted_condvar.notify_one(); // notify the main thread m_WorkCompleted_mutex.unlock(); } } ThreadPool::ThreadPool() { m_numOfThreads = 0; m_NumOfThreadsDoingWork = 0; m_NumOfThreadsGivenJobs = 0; } ThreadPool::~ThreadPool() { if(m_numOfThreads) { DestroyThreadPool(); delete [] m_ThreadData; } } void ThreadPool::CreateThreads(int numOfThreads) { // Check a thread pool has already been created if(m_numOfThreads > 0) return; m_NumOfThreadsGivenJobs = 0; m_NumOfThreadsDoingWork = 0; m_numOfThreads = numOfThreads; m_ThreadData = new ThreadData[m_numOfThreads]; ThreadArgStruct threadArg; for(int i=0; i<m_numOfThreads; ++i) { threadArg.threadId = i; threadArg.threadPoolInstance = this; // Creates the thread and save in a list so we can destroy it later m_ThreadList.push_back( new tthread::thread( ThreadFuncWrapper, (void *)&threadArg ) ); // It takes a little time for a thread to get established. // Best wait until it gets established before creating the next thread. m_ThreadReady_mutex.lock(); while(!m_ThreadData[i].ready) // Check if thread is ready m_ThreadReady_condvar.wait(m_ThreadReady_mutex); // If not, wait here m_ThreadReady_mutex.unlock(); } } // Adds a job to the batch, but doesn't start the job void ThreadPool::SubmitJob(void (*workFunc)(void *), void *workData) { // Check that the thread pool has been created if(!m_numOfThreads) return; if(m_NumOfThreadsGivenJobs >= m_numOfThreads) return; m_ThreadData[m_NumOfThreadsGivenJobs].workFunc = workFunc; m_ThreadData[m_NumOfThreadsGivenJobs].workData = workData; std::cout << "Submitted job " << m_NumOfThreadsGivenJobs << std::endl; m_NumOfThreadsGivenJobs++; } void ThreadPool::StartJobs() { // Check that the thread pool has been created // and some jobs have been assigned if(!m_numOfThreads || !m_NumOfThreadsGivenJobs) return; // Set 'haveworkToDo' flag for all threads m_WorkToDo_mutex.lock(); for(int i=0; i<m_NumOfThreadsGivenJobs; ++i) m_ThreadData[i].haveWorkToDo = true; m_NumOfThreadsDoingWork = m_NumOfThreadsGivenJobs; // Reset this counter so we can resubmit jobs later m_NumOfThreadsGivenJobs = 0; // Notify all threads they have work to do m_WorkToDo_condvar.notify_all(); m_WorkToDo_mutex.unlock(); } void ThreadPool::WaitForJobsToComplete() { // Check that a thread pool has been created if(!m_numOfThreads) return; m_WorkCompleted_mutex.lock(); while(m_NumOfThreadsDoingWork > 0) // Check if all threads have completed their work m_WorkCompleted_condvar.wait(m_WorkCompleted_mutex); // If not, wait here m_WorkCompleted_mutex.unlock(); } void ThreadPool::DestroyThreadPool() { std::cout << "Ask threads to quit\n"; m_WorkToDo_mutex.lock(); for(int i=0; i<m_numOfThreads; ++i) { m_ThreadData[i].haveWorkToDo = true; m_ThreadData[i].typeOfWork = e_quit; } m_WorkToDo_condvar.notify_all(); m_WorkToDo_mutex.unlock(); // As each thread terminates, catch them here for(int i=0; i<m_numOfThreads; ++i) { tthread::thread *t = m_ThreadList[i]; // Wait for thread to complete t->join(); } m_numOfThreads = 0; } Example of usage: (this calculates pi-squared/6) struct CalculationDataStruct { int inputVal; double outputVal; }; void LongCalculation( void *theSums ) { CalculationDataStruct *sums = (CalculationDataStruct *)theSums; int terms = sums->inputVal; double sum; for(int i=1; i<terms; i++) sum += 1.0/( double(i)*double(i) ); sums->outputVal = sum; } int main(int argc, char** argv) { int numThreads = 10; // Create pool ThreadPool threadPool; threadPool.CreateThreads(numThreads); // Create thread workspace CalculationDataStruct sums[numThreads]; // Set up jobs for(int i=0; i<numThreads; i++) { sums[i].inputVal = 3000*(i+1); threadPool.SubmitJob(LongCalculation, &sums[i]); } // Run the jobs threadPool.StartJobs(); threadPool.WaitForJobsToComplete(); // Print results for(int i=0; i<numThreads; i++) std::cout << "Sum of " << sums[i].inputVal << " terms is " << sums[i].outputVal << std::endl; return 0; } Question: In the ThreadPool::ThreadFunc method, would better performance be obtained if the following if statement if(NumOfThreadsDoingWork == 0) was included? Also, I'd be grateful of criticisms and ways to improve the code. At the same time, I hope the code is of use to others.

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  • MySQL Student database beginner SQL employment expectations

    - by sammysmall
    Background, Student pursuing BSIT degree, employer expectations, entry level. I would like to solicit opinions from this forum as to what your professional expectations are as regards an entry level position in working in the database realm... I see many job opportunities that require a minimum of 2 or more years experience, how does one go about obtaining this experience (I have tried very hard to maintain a minimum 3.70+ GPA) but have ZERO work experience in this field... I spend non school time working in VB and SQL to try and increase my proficiency. I have considered postponing my job search until I obtain certifications from brainbench etc... Any criticism and or advise is welcomed... Again I have no experience in database other than undergrad work in class. Thank you for your time sammysmall

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  • Trying to setup postfix

    - by Frexuz
    I used this guide: http://jonsview.com/how-to-setup-email-services-on-ubuntu-using-postfix-tlssasl-and-dovecot telnet localhost 25 says 220 episodecalendar.com ESMTP Postfix (Ubuntu) ehlo localhost 250-episodecalendar.com 250-PIPELINING 250-SIZE 10240000 250-VRFY 250-ETRN 250-STARTTLS 250-AUTH LOGIN PLAIN 250-AUTH=LOGIN PLAIN 250-ENHANCEDSTATUSCODES 250-8BITMIME 250 DSN Installation seems fine? /var/log/mail.log says Nov 26 14:04:06 ubuntu postfix/pickup[12107]: A742E2B9E1: uid=0 from=<root> Nov 26 14:04:06 ubuntu postfix/cleanup[12114]: A742E2B9E1: message-id=<[email protected]> Nov 26 14:04:06 ubuntu postfix/qmgr[12108]: A742E2B9E1: from=<[email protected]>, size=300, nrcpt=1 (queue active) Nov 26 14:04:06 ubuntu postfix/local[12115]: A742E2B9E1: to=<[email protected]>, relay=local, delay=3.3, delays=3.3/0/0/$ Nov 26 14:04:06 ubuntu postfix/cleanup[12114]: AD2662B9E0: message-id=<[email protected]> Nov 26 14:04:06 ubuntu postfix/qmgr[12108]: AD2662B9E0: from=<>, size=2087, nrcpt=1 (queue active) Nov 26 14:04:06 ubuntu postfix/bounce[12117]: A742E2B9E1: sender non-delivery notification: AD2662B9E0 Nov 26 14:04:06 ubuntu postfix/local[12115]: AD2662B9E0: to=<[email protected]>, relay=local, delay=0.02, delays=0.01/0/0/0$ Nov 26 14:04:06 ubuntu postfix/qmgr[12108]: AD2662B9E0: removed Nov 26 14:04:06 ubuntu postfix/qmgr[12108]: A742E2B9E1: removed I'm not really understanding the log file, and obviously I'm not getting any emails. Right now I'm running Ubuntu on a Virtualbox (development box). Is that a problem? The internet connection works fine on it. What about domains etc..? edit: /etc/postfix/main.cf # See /usr/share/postfix/main.cf.dist for a commented, more complete version # Debian specific: Specifying a file name will cause the first # line of that file to be used as the name. The Debian default # is /etc/mailname. #myorigin = /etc/mailname smtpd_banner = $myhostname ESMTP $mail_name (Ubuntu) biff = no # appending .domain is the MUA's job. append_dot_mydomain = no # Uncomment the next line to generate "delayed mail" warnings #delay_warning_time = 4h readme_directory = no # TLS parameters smtpd_tls_cert_file = /etc/postfix/ssl/smtpd.crt smtpd_tls_key_file = /etc/postfix/ssl/smtpd.key smtpd_use_tls = yes smtpd_tls_session_cache_database = btree:${data_directory}/smtpd_scache smtp_tls_session_cache_database = btree:${data_directory}/smtp_scache # See /usr/share/doc/postfix/TLS_README.gz in the postfix-doc package for # information on enabling SSL in the smtp client. # See /usr/share/postfix/main.cf.dist for a commented, more complete version # Debian specific: Specifying a file name will cause the first # line of that file to be used as the name. The Debian default # is /etc/mailname. #myorigin = /etc/mailname smtpd_banner = $myhostname ESMTP $mail_name (Ubuntu) biff = no # appending .domain is the MUA's job. append_dot_mydomain = no # Uncomment the next line to generate "delayed mail" warnings #delay_warning_time = 4h readme_directory = no # TLS parameters smtpd_tls_cert_file = /etc/postfix/ssl/smtpd.crt smtpd_tls_key_file = /etc/postfix/ssl/smtpd.key smtpd_use_tls = yes smtpd_tls_session_cache_database = btree:${data_directory}/smtpd_scache smtp_tls_session_cache_database = btree:${data_directory}/smtp_scache # See /usr/share/doc/postfix/TLS_README.gz in the postfix-doc package for # information on enabling SSL in the smtp client.

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  • Access / Excel crossover: Should i attach spreadsheets to records

    - by glinch
    Hi, I currently have an archaic system of client records that I am trying to improve. For each client i have a directory, in that directory i include a directory for each job. Each job has a spreadsheet that i use to store their personal details, and run calculations and costings specific to their needs. In turn I also have word documents that are linked to their spreadsheet which automatically update accordingly. The spreadsheet is also exported as a pdf as well I am trying to build a database of customer records in Access, straight forward enough. For each new customer i need to be able to add the appropriate spreadsheet to their records, update the spreadsheet accordingly with their details, use the spreadsheet to calculate their costings etc.. I do not want to enter the same information repeatedly, and would like a cohesive system, with data being passed between access and excel. Should this be easy enough to do with the two packages? Thanks in advance Noel

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  • RabbitMQ and persistence (blocking writes?)

    - by daharon
    I want to create a RabbitMQ server on a virtual machine (VMware) to be used in production. It will contain persistent queues. I'm wondering if it is a bad idea to store the server on a NAS that's accessed over NFS. Basically my questions are: Will RabbitMQ's writes be blocking? Will the entire queue's operation halt on a write? How much performance degradation should I expect when persisting over NFS?

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  • Are government programming jobs good?

    - by Absolute0
    I am a passionate software developer and greatly enjoy programming. However I was recently contacted regarding a developer lead position for a government job at NYC for the fire department. The pay is pretty good, and I would assume the position has good job security and stability. But I am hesitant to even go for an interview as it seems like an exaggerated version of Office Space with a lot of Bureaucracy and mindless paper work. The description is as follows: The Lead Applications Developer, supporting the Programming Group, will be responsible for all phases of the system development life cycle including performing system analysis, requirements definition, database design, preparation of scopes of work, and development of project plans. Supervise programming staff and manage projects involving the design, implementation, maintenance, and enhancement of complex Oracle based user applications using Oracle Development tools. Applications will be deployed using Oracle Application Server utilizing programming languages such as JAVA, JSF, JSP, Oracle ADF, PL/SQL, and XML with J2EE and EJB technology. Anyone with previous government experience can share their two cents on this? Thank you.

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  • Normalization in plain English

    - by Yada
    I sort of understand the concept of database normalization but always have a hard time explaining it in plain English especially for a job interview. I have read the wikipedia post, but still find it hard to explain the concept to none developers. "Design a database in a way not to get duplicated data" is the first thing that comes to mind. Does anyone was a nice way to explain the concept of database normalization in plain English. And what are some nice examples to show the differences between first, second and third normal forms. Say you go to a job interview and the person asks: Explain the concept of normalization and how would go about designing a normalized database. What key points are the interviewer looking for?

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  • Handling Exceptions for ThreadPoolExecutor

    - by HonorGod
    I have the following code snippet that basically scans through the list of task that needs to be executed and each task is then given to the executor for execution. The JobExecutor intern creates another executor (for doing db stuff...reading and writing data to queue) and completes the task. JobExecutor returns a Future for the tasks submitted. When one of the task fails, I want to gracefully interrupt all the threads and shutdown the executor by catching all the exceptions. What changes do I need to do? public class DataMovingClass { private static final AtomicInteger uniqueId = new AtomicInteger(0); private static final ThreadLocal<Integer> uniqueNumber = new IDGenerator(); ThreadPoolExecutor threadPoolExecutor = null ; private List<Source> sources = new ArrayList<Source>(); private static class IDGenerator extends ThreadLocal<Integer> { @Override public Integer get() { return uniqueId.incrementAndGet(); } } public void init(){ // load sources list } public boolean execute() { boolean succcess = true ; threadPoolExecutor = new ThreadPoolExecutor(10,10, 10, TimeUnit.SECONDS, new ArrayBlockingQueue<Runnable>(1024), new ThreadFactory() { public Thread newThread(Runnable r) { Thread t = new Thread(r); t.setName("DataMigration-" + uniqueNumber.get()); return t; }// End method }, new ThreadPoolExecutor.CallerRunsPolicy()); List<Future<Boolean>> result = new ArrayList<Future<Boolean>>(); for (Source source : sources) { result.add(threadPoolExecutor.submit(new JobExecutor(source))); } for (Future<Boolean> jobDone : result) { try { if (!jobDone.get(100000, TimeUnit.SECONDS) && success) { // in case of successful DbWriterClass, we don't need to change // it. success = false; } } catch (Exception ex) { // handle exceptions } } } public class JobExecutor implements Callable<Boolean> { private ThreadPoolExecutor threadPoolExecutor ; Source jobSource ; public SourceJobExecutor(Source source) { this.jobSource = source; threadPoolExecutor = new ThreadPoolExecutor(10,10,10, TimeUnit.SECONDS, new ArrayBlockingQueue<Runnable>(1024), new ThreadFactory() { public Thread newThread(Runnable r) { Thread t = new Thread(r); t.setName("Job Executor-" + uniqueNumber.get()); return t; }// End method }, new ThreadPoolExecutor.CallerRunsPolicy()); } public Boolean call() throws Exception { boolean status = true ; System.out.println("Starting Job = " + jobSource.getName()); try { // do the specified task ; }catch (InterruptedException intrEx) { logger.warn("InterruptedException", intrEx); status = false ; } catch(Exception e) { logger.fatal("Exception occurred while executing task "+jobSource.getName(),e); status = false ; } System.out.println("Ending Job = " + jobSource.getName()); return status ; } } }

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  • Hadoop 0.2: How to read outputs from TextOutputFormat?

    - by S.N
    My reducer class produces outputs with TextOutputFormat (the default OutputFormat given by Job). I like to consume this outputs after the MapReduce job complete to aggregate the outputs. In addition to this, I like to write out the aggregated information with TextInputFormat so that the output from this process can be consumed by the next iteration of MapReduce task. Can anyone give me an example on how to write & read with TextFormat? By the way, the reason why I am using TextFormat, rather Sequence, is the interoperability. The outputs should be consumed by any software.

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  • Running Awk command on a cluster

    - by alex
    How do you execute a Unix shell command (awk script, a pipe etc) on a cluster in parallel (step 1) and collect the results back to a central node (step 2) Hadoop seems to be a huge overkill with its 600k LOC and its performance is terrible (takes minutes just to initialize the job) i don't need shared memory, or - something like MPI/openMP as i dont need to synchronize or share anything, don't need a distributed VM or anything as complex Google's SawZall seems to work only with Google proprietary MapReduce API some distributed shell packages i found failed to compile, but there must be a simple way to run a data-centric batch job on a cluster, something as close as possible to native OS, may be using unix RPC calls i liked rsync simplicity but it seem to update remote notes sequentially, and you cant use it for executing scripts as afar as i know switching to Plan 9 or some other network oriented OS looks like another overkill i'm looking for a simple, distributed way to run awk scripts or similar - as close as possible to data with a minimal initialization overhead, in a nothing-shared, nothing-synchronized fashion Thanks Alex

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