locks

When I try to drop a table, MySQL hangs. I don't have any other open sessions. How to resolve this? I have waited for 10 hours and the process has not terminated. Sebas Waiting for table metadata lock drop table tableA name SELECT l1.lat, l1.lon, l2.zipcode FROM tableA l1, tableBl2 where l1.lat = l2.latitude and l1.lon = l2.longitude limit 10 If this is your table, see this link you have an implicit deadlock. Kill the other transactions to release the drop, or kill the drop to release the other transactions. You can use KILL thread_id, in sql_plus. I'm adding further information since I came

Are Locks AutoCloseable? That is, instead of: Lock someLock = new ReentrantLock(); someLock.lock(); try { // ... } finally { someLock.unlock(); } can I say: try (Lock someLock = new ReentrantLock()) { someLock.lock(); // ... } in Java 7? dlev No, neither the Lock interface (nor the ReentrantLock class) implement the AutoCloseable interface, which is required for use with the new try-with-resource syntax. If you wanted to get this to work, you could write a simple wrapper: public class LockWrapper implements AutoCloseable { private final Lock _lock; public LockWrapper(Lock l) { this._lock = l;

What are best practices or work-arounds for using both multiprocessing and user threads in the same python application in Linux with respect to Issue 6721, Locks in python standard library should be sanitized on fork? Why do I need both? I use child processes to do heavy computation that produce data structure results that are much too large to return through a queue -- rather they must be immediately stored to disk. It seemed efficient to have each of these child processes monitored by a separate thread, so that when finished, the thread could handle the IO of reading the large (eg multi GB)