deadlock

问题 I would like to understand better a mechanism of locking in postgres. Let's say that tree can have apples (via foreign key on apple table). It seems that when selecting a tree for update lock is obtained on an apple. However, the operation is not blocked even if someone else already holds a lock on this apple. Why is it so? p.s. Please don't suggest to remove "select for update". Scenario Transaction 1 Transaction 2 BEGIN . update apple; . . BEGIN . select tree for update; . update apple; . -

问题 I know that deadlocks occur inevitably when using transactions in Innodb and that they are harmless if they are treated properly by the application code - "just try it again", as the manual says. So I was wondering - how do you detect deadlocks? Does a deadlock issue some special mysql error number? I am using PHP's mysqli extension if that matters. Thank you. Edit: solution found, see comments 回答1: http://dev.mysql.com/doc/refman/5.0/en/innodb-error-codes.html 1213 (ER_LOCK_DEADLOCK)

问题 In my application, I am performing my file reading by another thread(other that GUI thread). There are two buttons that suspend and resume the Thread respectively. private void BtnStopAutoUpd_Click(object sender, EventArgs e) { autoReadThread.Suspend(); } private void BtnStartAutoUpd_Click(object sender, EventArgs e) { autoReadThread.Resume(); } but I am facing this warning, Thread.Suspend has been deprecated. Please use other classes in System.Threading, such as Monitor, Mutex, Event, and

问题 In my application, I am performing my file reading by another thread(other that GUI thread). There are two buttons that suspend and resume the Thread respectively. private void BtnStopAutoUpd_Click(object sender, EventArgs e) { autoReadThread.Suspend(); } private void BtnStartAutoUpd_Click(object sender, EventArgs e) { autoReadThread.Resume(); } but I am facing this warning, Thread.Suspend has been deprecated. Please use other classes in System.Threading, such as Monitor, Mutex, Event, and

问题 I was just trying to create a Thread in a static block in Java that caused a deadlock to occur. The code snippet is as follows. package deadlock; final public class Main { static int value; static { final Thread t = new Thread() { @Override public void run() { value = 1; } }; t.start(); System.out.println("Deadlock detected"); try { t.join(); } catch (InterruptedException e) { System.out.println(e.getMessage()); } System.out.println("Released"); } public static void main(String...args) { /

问题 It should be careful to use several awaits on same Task. I have encountered with such situation while trying to use BlockingCollection.GetConsumingEnumerable() method. And ends up with this simplified test. class TestTwoAwaiters { public void Test() { var t = Task.Delay(1000).ContinueWith(_ => Utils.WriteLine("task complete")); var w1 = FirstAwaiter(t); var w2 = SecondAwaiter(t); Task.WaitAll(w1, w2); } private async Task FirstAwaiter(Task t) { await t; //await t.ContinueWith(_ => { }); Utils

问题 I currently have a Plone 4.3.8 site where editing a portlet causes a deadlock. I'm trying to find tools to fix this, but most deadlock tools don't work & I'm not getting good information (IMO) from those that at least run. I've tried: z3c.deadlockdebugger => can't get to a stacktrace ZopeHealthWatcher => can't see the results on command line (or webpage) Products.LongRequestLogger => perhaps the best so far, gives me some log output - but it's stack traces focus on Diazo code, but the problem

问题 This question already has answers here : Why does parallel stream with lambda in static initializer cause a deadlock? (3 answers) Closed last year . The following code leads to deadlock(on my pc): public class Test { static { final int SUM = IntStream.range(0, 100) .parallel() .reduce((n, m) -> n + m) .getAsInt(); } public static void main(String[] args) { System.out.println("Finished"); } } But if I replace reduce lambda argument with anonymous class it doesn't lead to deadlock: public class

问题 I am using a LogAppender class which extends a Console Appender and internally uses a Sendmail function to send mails if the log level is ERROR. (I know I could have used a SMPT appender for mailing, but this is how the infrastructure is so any please avoid any comments on this). My application is split into different threads, and the issue mentioned below happends sporadically.(But some observation tells me that it might be due to one thread taking more time to initalize). I get the

问题 I am using a LogAppender class which extends a Console Appender and internally uses a Sendmail function to send mails if the log level is ERROR. (I know I could have used a SMPT appender for mailing, but this is how the infrastructure is so any please avoid any comments on this). My application is split into different threads, and the issue mentioned below happends sporadically.(But some observation tells me that it might be due to one thread taking more time to initalize). I get the