deadlock

问题 This is an interview question . In general the deadlock between 2 threads is generated when thread1 locks mutex1,and a moment before it tries to lock mutex2 ,thread 2 locks mutex2.After that tread 2 wants to lock mutex1.So they wait for each other forever. The question was "Can you gave a scenario of deadlock with one mutex and any number of threads?" 回答1: It depends on how you define "deadlock" I guess, but I could see one possibility: Thread A grabs the mutex Thread B waits for mutex Thread

问题 This is an interview question . In general the deadlock between 2 threads is generated when thread1 locks mutex1,and a moment before it tries to lock mutex2 ,thread 2 locks mutex2.After that tread 2 wants to lock mutex1.So they wait for each other forever. The question was "Can you gave a scenario of deadlock with one mutex and any number of threads?" 回答1: It depends on how you define "deadlock" I guess, but I could see one possibility: Thread A grabs the mutex Thread B waits for mutex Thread

问题 The following code runs into future timeouts (in Scala 2.x and Dotty, -Xcheckinit or -Ycheck-init does not help here) because of cyclic object initialization. In complex projects these cycles usually are hidden very well. Is there any possiblity of getting help from the compiler or at least at runtime? How do you prevent this from happening in a multithreaded environment? import scala.concurrent.Future import scala.concurrent._ import scala.concurrent.duration._ import scala.concurrent

问题 I use a c++ class that encapsulates a boost::asio::io_service . class IoService { public: static IoService& getInstance() { static IoService instance; return instance; } void start() { _ioServiceThread = std::thread(&IoService::run, this); } void stop() { _ioService.stop(); _ioServiceThread.join(); } void run() { _ioService.run(); } private: IoService(); ~IoService(); IoService(const IoService& old) = delete; IoService(const IoService&& old) = delete; IoService& operator=(const IoService& old

问题 I use a c++ class that encapsulates a boost::asio::io_service . class IoService { public: static IoService& getInstance() { static IoService instance; return instance; } void start() { _ioServiceThread = std::thread(&IoService::run, this); } void stop() { _ioService.stop(); _ioServiceThread.join(); } void run() { _ioService.run(); } private: IoService(); ~IoService(); IoService(const IoService& old) = delete; IoService(const IoService&& old) = delete; IoService& operator=(const IoService& old

问题 I found out some rare deadlock errors happening. I understand deadlock happens when two queries job depends on the result of each other so MySQL rollbacks one of them. But in my situation MySQL is in auto commit mode and I am inserting a new record which fires a trigger. So I don't get the reason it produces a dead lock situation. Here is my tables schema: ---- users Table ---- CREATE TABLE `users` ( `insta_id` bigint(20) unsigned NOT NULL, `name` varchar(50) NOT NULL, `password` varchar(60)

问题 I found out some rare deadlock errors happening. I understand deadlock happens when two queries job depends on the result of each other so MySQL rollbacks one of them. But in my situation MySQL is in auto commit mode and I am inserting a new record which fires a trigger. So I don't get the reason it produces a dead lock situation. Here is my tables schema: ---- users Table ---- CREATE TABLE `users` ( `insta_id` bigint(20) unsigned NOT NULL, `name` varchar(50) NOT NULL, `password` varchar(60)

问题 How do we prevent SQL Implicit Conversions in Dapper? We realized, we were conducting an SQL Implicit conversion, causing an Index Scan and Deadlocks. Dapper parameters are nvarchar, while SQL table columns are varchar. This caused all our sql columns convert into nvarchar. We fixed the issue by going through all our embedded Dapper code and converting columns as cast(@SSN as varchar(9)), cast(@LastName as varcarh(25)), cast(@EmployeeId as varchar(10) There has got to be an easier way, is

问题 How do we prevent SQL Implicit Conversions in Dapper? We realized, we were conducting an SQL Implicit conversion, causing an Index Scan and Deadlocks. Dapper parameters are nvarchar, while SQL table columns are varchar. This caused all our sql columns convert into nvarchar. We fixed the issue by going through all our embedded Dapper code and converting columns as cast(@SSN as varchar(9)), cast(@LastName as varcarh(25)), cast(@EmployeeId as varchar(10) There has got to be an easier way, is

问题 I was doing a set of 10 concurrent tests when ClickHouse became deadlocked. The following SQL select id, sum(a) as a, sum(b) as b, sum(c) as c, round(sum(d), 2) as d from f_table where xxx And I ran pstack my-clickhouse-server-process-id and got some __lll_lock_wait . Sorry for posting so many thread stack logs, I thought more information may give you some ideas. Since this reproduce is not stable at present, I haven't posted it on GitHub's issue. I read https://github.com/ClickHouse