notify

问题 I'm trying to handle multiple connections on the same port of my server. I'm doing this by instantiating an Object and passing it into the constructor for another class, which implements Runnable. Then I set up a socket in the Runnable class and call notify() on the passed Object after a Client connects on the port. This should then allow the server to restart its loop, creating another instance of the Runnable class after being notified. However, currently the wait() isnt being reached until

问题 I am planning to use postgres LISTEN/NOTIFY aproach to get insert time(actual transaction commit time) of records in a table. To achieve this, I plan to do the following. I issue a notification during insert time as shown below. BEGIN; INSERT INTO table_name(id, ...) values (id,....); select pg_notify('test_channel', 'id - ' || id || ' trans start time - ' || now() || ' notify start time - ' || clock_timestamp()); END; And then I plan to use https://pythonhosted.org/psycopg2/advanced.html

问题 My question is very similar to this one except that my background process was started from a script. I could be doing something wrong but when I try this simple example: #!/bin/bash set -mb # enable job control and notification sleep 5 & I never receive notification when the sleep background command finishes. However, if I execute the same directly in the terminal, $ set -mb $ sleep 5 & $ [1]+ Done sleep 5 I see the output that I expect. I'm using bash on cygwin. I'm guessing that it might

问题 I am trying to call wait() function on the "slp" object, then after 1000 mills wake it up, but instead of message "Finished ..." I get an "IllegalMonitorStateException" error, after calling notify() class Class1 extends Thread{ boolean newTxt = false; private Sleep slp = null; synchronized public void put(Sleep slp) { thus.slp = slp; try{ slp.wait();}catch(Exception x){} } synchronized public void wakeup() { slp.notify(); } public void run() { while(slp == null ); try{ sleep(1000);}catch

问题 I've been using an HTTP POST to a php file to change entries in a given MySQL database. Essentially, the second the value changes, I would like the user that is viewing the database table to be notified. For now my temporary solution is to auto refresh a page displaying the table to keep it updated but I feel like there has to be a more efficient way of going about this. 回答1: Do you really have to update it in the same second? It looks like a server killer feature. Read about Comet, maybe it

问题 i'm newbie for postgresql, now i try to get notification from db when that table (my table name is foo2) have insert or update but not have anything return from db to my code with c# project This is my code // -------------- create table --------------- CREATE TABLE foo2 (id serial primary key, name varchar); // -------------- create function ------------ CREATE OR REPLACE FUNCTION nf() RETURNS TRIGGER AS $$ BEGIN PERFORM pg_notify('notifytest', format('INSERT %s %s', NEW.id, NEW.name));

问题 I recently discovered that using synchronized won't prevent any dead locks. E.g. within this code: ArrayList <Job> task; ... public void do(Job job){ synchronized(tasks){ tasks.add(job); } synchronized(this){ notify(); } } public void run(){ while(true){ for (int = 0;i<tasks.size();i++){ synchronized(tasks){ Job job = tasks.get(i); } //do some job here... } synchronized(this){ wait(); //lock will be lost... notifier = false; //lock will be acquired again after notify() } } } Now, what is the

问题 PostgreSQL has a good listen/notify system. Documentation says: There is a queue that holds notifications that have been sent but not yet processed by all listening sessions. If this queue becomes full, transactions calling NOTIFY will fail at commit. But I can't find out what happening with events in a specified channel that doesn't have listeners. Will notification queue overflow or will PG drop these events from queue? 回答1: It could be more clear in the manual, but there is definitive

问题 Alternatively, I could use something like viewWillAppear, only switching tabs doesn't call viewWillAppear - IF I can access selectedItem or selectedIndex reliably from there. The goal is to re-use a similar table view, with 3 tabs filling the table with differently filtered data. I tried overriding didSelect and using the app delegate as UITabBarDelegate, but got the error 'Changing the delegate of a tab bar managed by a tab bar controller is not allowed.' The tab bar controller, rootCt, is

问题 So I have been working on a simple wait/notify example in Java and for some reason I have not been able to get it to run properly. If anyone is able to see what might be the issue It would be very appreciated! public class ThreadDemonstration { private String str = null; Thread stringCreator = new Thread(new Runnable() { public void run() { synchronized(this) { str = "I have text"; notify(); } } }); private Thread stringUser = new Thread(new Runnable() { public void run() { synchronized(this)