locking

问题 Hi I am using gunicorn with nginx and a postgreSQL database to run my web app. I recently change my gunicorn command from gunicorn run:app -w 4 -b 0.0.0.0:8080 --workers=1 --timeout=300 to gunicorn run:app -w 4 -b 0.0.0.0:8080 --workers=2 --timeout=300 using 2 workers. Now I am getting error messages like File "/usr/local/lib/python2.7/dist-packages/flask_sqlalchemy/__init__.py", line 194, in session_signal_after_commit models_committed.send(session.app, changes=list(d.values())) File "/usr

问题 I have been reading this thread about detecting a locked file , and now I would like to implement it in my scripts, so I will need a way to programatically detect it in Windows shell scripting . The accepted solution gives a way to hold a file open/locked: ( >&2 pause ) >> test.txt but this solution needs a key pressing . I would like to create a Windows shell script similar, like this: [Create and locking of c:\Temp\ProgramRunning.lck] --------------- Rest of the Script --------------- [Blah

问题 Does it mean that any Thread irrespective of the object it obtain will not interfere other Thread executing in Synchronized static method. Even if we call with class_name.static_Method. Ex- If we have two thread : public class Test implements Runnable { public synchronized static testMethod(){} public void run(){ testMethod(); } public static void main(String[] args) { Test obj1=new Test(); Test obj2=new Test(); Thread t1=new Thread(obj1); Thread t2=new Thread(obj2); t1.start(); // thread on

问题 The following code throws a 110 Error on the EndUpdateResource call only when windows explorer is open at D:\test\output\ where the executable is being copied to: std::ifstream in("C:\\Windows\\notepad.exe", std::ios::binary); std::ofstream out("D:\\test\\output\\notepad.exe", std::ios::binary); out << in.rdbuf(); in.close(); out.close(); Handle hUpdateRes = BeginUpdateResource(_T("D:\\test\\output\\notepad.exe"), FALSE); EndUpdateResource(hUpdateRes, FALSE); As long as I don't have that

问题 Consider the following pseudo-code in C++: // somewhere in common code, properly scoped boost::mutex data_ready_lock; bool data_ready; // Thread 1: void SomeThreadFunc() { // ... push data onto a shared data structure that is properly locked data_ready_lock.lock(); data_ready = true; data_ready_lock.unlock(); } // Thread 2: (actually a function called from the main() thread) // Returns the number of bytes written to output_data size_t RequestData(uint8_t* const output_data) { data_ready_lock

问题 To avoid race conditions, I need to use select for update functionality while querying database so that it locks the row until the end of the transaction. Since select_for_update query is not present in Django 1.3, I have done a workaround it by using a class method which returns query sets by doing a raw sql query. #models.py class AccountDetails(models.Model): user = models.OneToOneField(User) amount = models.IntegerField(max_length=15,null=True,blank=True) @classmethod def get_locked_for

问题 We used Delphi 6 long times ago. Our problem, that Delphi have two problems with DFMs: 1.) When some linked resource (like DataSet) will removed, Delphi many times forget to ask you that "some of the resources are linked, you need to redirect...". This happens, when the actual form is not added to the project, or it is not opened. 2.) When we only open the DFM, and only see some thing, may we change it (active TabSheet, form position). Then Delphi auto save the form - and sometimes it drops

问题 Do I understand correctly that table/row lock hints are being used for pessimistic transaction (TX) isolation models of concurrency ONLY ? In other words, when can table/row lock hints be used during engagement of optimistic TX isolation provided by SQL Server (2005 and higher)? When one would need pessimistic TX isolation levels/hints in SQL Server2005+ if the later provides built-in optimistic (aka snapshot aka versioning) concurrency isolation? I did read that pessimistic options are

问题 There's a strange situation happening in my iOS application when it receive push notification. The UI stay locked and nothing works. When I pause the debugger I see semaphore_wait_trap in my thread. Debbuging the code I can see it is related to two things: the value type in push notification (because when I change Number to String the problem disappear); the isRegisteredForRemoteNotifications method (because when I remove it the problem disappear); I'm receiving a push notification as follow

问题 I have created a WCF service with the configuration as InstanceMode=PerCall and ConcurrencyMode=Multiple. But I am getting problem in the synchronization with one of the instance method. It sometimes does not get called with right set of Class property values. [ServiceBehavior(InstanceContextMode = InstanceContextMode.PerCall, ConcurrencyMode = ConcurrencyMode.Multiple)] public class InvestorService : IInvestorService public void ProcessPartnerChunk(short PartnerChunkTypeId, int JobID, int?