locking

问题 I have a flash application that I am going to put up on my website shortly. I want to be able to "lock it" to the site to prevent: Hosting the .SWF on another site (after an illicit download), and Preventing the .SWF from opening if included in an iFrame on another site While allowing: A whitelist of sites to be passed through/enabled without me having to define all the variations of a URL (ie: www.abc.com, abc.com, abc.com/game/, games.abc.com, etc.) There are commercial applications that

问题 I have got the error Lock wait timeout exceeded; try restarting transaction . What are the reasons for this and how to solve the problem? FYI: innodb_lock_wait_timeout = 100 in MySQL config file. 回答1: This is problem of lock contention , which ultimately result in a time-out on one of the lock. Here are a few suggestions: Make sure you have the correct indexes which result in row-level locks not table-level lock. This will reduce the contention. Make sure you have indexes on the foreign key

问题 I have got the error Lock wait timeout exceeded; try restarting transaction . What are the reasons for this and how to solve the problem? FYI: innodb_lock_wait_timeout = 100 in MySQL config file. 回答1: This is problem of lock contention , which ultimately result in a time-out on one of the lock. Here are a few suggestions: Make sure you have the correct indexes which result in row-level locks not table-level lock. This will reduce the contention. Make sure you have indexes on the foreign key

问题 I have got the error Lock wait timeout exceeded; try restarting transaction . What are the reasons for this and how to solve the problem? FYI: innodb_lock_wait_timeout = 100 in MySQL config file. 回答1: This is problem of lock contention , which ultimately result in a time-out on one of the lock. Here are a few suggestions: Make sure you have the correct indexes which result in row-level locks not table-level lock. This will reduce the contention. Make sure you have indexes on the foreign key

问题 In GAE, I've got a table full of "one offs" -- things like "last-used sequence number" and the like that don't really fall into other tables. It's a simple String-key with String-value pair. I've got some code to grab a named integer and increment it, like so: @PersistenceCapable(detachable="true") public class OneOff { @PrimaryKey @Persistent(valueStrategy = IdGeneratorStrategy.IDENTITY) private Key key; @Persistent private String dataKey; @Persistent private String value; public OneOff

问题 I have a Dictionary that tracks objects (ClientObject). Both the dictionary and ClientObject's are accessed by multiple threads. When I modify or read any object in this dictionary, I obtain a read or write lock on the dictionary using ReaderWriterLockSlim (rwl_clients) then obtain an exclusive lock on the actual object. I just wanted to know if I am using these .net threading facilities correctly Example: rwl_clients.EnterReadLock(); ClientObject clobj; if(!m_clients.TryGetValue(key, out

问题 I have a Dictionary that tracks objects (ClientObject). Both the dictionary and ClientObject's are accessed by multiple threads. When I modify or read any object in this dictionary, I obtain a read or write lock on the dictionary using ReaderWriterLockSlim (rwl_clients) then obtain an exclusive lock on the actual object. I just wanted to know if I am using these .net threading facilities correctly Example: rwl_clients.EnterReadLock(); ClientObject clobj; if(!m_clients.TryGetValue(key, out

问题 According to innodb lock mode lock type compatibility matrix X IX S IS X Conflict Conflict Conflict Conflict IX Conflict Compatible Conflict Compatible S Conflict Conflict Compatible Compatible IS Conflict Compatible Compatible Compatible IX is compatible with IX, but the fact is if we acquire one IX lock by select c1 from z where c1 = 1 for update in session 1, trying to acquire IX by select c1 from z where c1 = 1 for update will be blocked in session 2, so I think they are not compatible.

问题 I've written a read-write lock using Python's concurrency primitives (I think!). Every implementation I've read on SO or elsewhere seems to use 2 locks -- one for reads, and another for writes. My implementation contains only one monitor for reads, but I may be missing something crucial -- can anyone confirm that this will work? If so, what is the benefit to using an additional write lock? This is the classic read-write lock with preference for readers (may starve writers). I use a dummy

问题 I've written a read-write lock using Python's concurrency primitives (I think!). Every implementation I've read on SO or elsewhere seems to use 2 locks -- one for reads, and another for writes. My implementation contains only one monitor for reads, but I may be missing something crucial -- can anyone confirm that this will work? If so, what is the benefit to using an additional write lock? This is the classic read-write lock with preference for readers (may starve writers). I use a dummy