concurrency

问题 As per this solution (https://stackoverflow.com/a/18923091/529618) I am using a ConcurrentDictionary<T,byte> as a workaround for the lack of ConcurrentHashSet<T> . However, I'm struggling to see how I can get the original T Key back out of the dictionary in O(1) time. var cache = new ConcurrentDictionary<MyEquatableClass, byte>()); //... if(!cache.TryAdd(classInstance, Byte.MinValue)) return /* Existing cache entry */; return classInstance; Is there any way to get the KeyValuePair<K,V> (or

问题 I am trying to write the unit test case for ListenableFuture adding Callback but I am not sure how to do it. Didn`t get anything useful on internet. @Test public void can_publish_data_to_kafka() { String topic = someString(10); String key = someAlphanumericString(5); String data = someString(50); SendResult sendResult = mock(SendResult.class); ListenableFuture<SendResult<String, Object>> future = mock(ListenableFuture.class); given(kafkaTemplate.send(topic, key, data)).willReturn(future);

问题 I am trying to write the unit test case for ListenableFuture adding Callback but I am not sure how to do it. Didn`t get anything useful on internet. @Test public void can_publish_data_to_kafka() { String topic = someString(10); String key = someAlphanumericString(5); String data = someString(50); SendResult sendResult = mock(SendResult.class); ListenableFuture<SendResult<String, Object>> future = mock(ListenableFuture.class); given(kafkaTemplate.send(topic, key, data)).willReturn(future);

问题 It is fairly easy to do parallel work with Python 3's concurrent.futures module as shown below. with concurrent.futures.ThreadPoolExecutor(max_workers=10) as executor: future_to = {executor.submit(do_work, input, 60): input for input in dictionary} for future in concurrent.futures.as_completed(future_to): data = future.result() It is also very handy to insert and retrieve items into a Queue. q = queue.Queue() for task in tasks: q.put(task) while not q.empty(): q.get() I have a script running

问题 It is fairly easy to do parallel work with Python 3's concurrent.futures module as shown below. with concurrent.futures.ThreadPoolExecutor(max_workers=10) as executor: future_to = {executor.submit(do_work, input, 60): input for input in dictionary} for future in concurrent.futures.as_completed(future_to): data = future.result() It is also very handy to insert and retrieve items into a Queue. q = queue.Queue() for task in tasks: q.put(task) while not q.empty(): q.get() I have a script running

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

问题 I have several scripts. Each of them does some computation and it is completely independent from the others. Once these computations are done, they will be saved to disk and a record updated. The record is maintained by an instance of a class, which saves itself to disks. I would like to have a single record instance used in multiple scripts (for example, record_manager = RecordManager(file_on_disk) . And then record_manager.update(...) ); but I can't do this right now, because when updating

问题 I'm trying to set up a server-side cache properly and I'm looking for constructive criticism on the setup I have currently. The cache is loaded when the Servlet starts and never changed again, so in effect it's a read-only cache. It obviously needs to stay in memory for the lifetime of the Servlet. Here's how I have it set-up private static List<ProductData> _cache; private static ProductManager productManager; private ProductManager() { try { lookup(); } catch (Exception ex) { _cache = null;

问题 I'm trying to set up a server-side cache properly and I'm looking for constructive criticism on the setup I have currently. The cache is loaded when the Servlet starts and never changed again, so in effect it's a read-only cache. It obviously needs to stay in memory for the lifetime of the Servlet. Here's how I have it set-up private static List<ProductData> _cache; private static ProductManager productManager; private ProductManager() { try { lookup(); } catch (Exception ex) { _cache = null;

问题 I wrote this test program: await Promise.anyof( Promise.allof((^5).map: {start { sleep 10; say "done $_" } }), Promise.in(5).then: { say 'ouch' } ); sleep 10; When the second promise times out it prints 'ouch' and the await exits, but the first promise's code block is still running. After five more seconds its five processes end and print 'done': $ ./test1.p6 ouch done 0 done 1 done 2 done 3 done 4 I tried to terminate the first promise assigning it to a variable and then calling the .break