Create Multiple Threads that access the database simultaneously - mysql

Question

I have tried to locate the solutions to my problem in various message boards. However, I am running into walls. I am trying to recreate a problem that is happening on our database "LockWait Timeout" on a Mysql INNODB table. (for information about my issue I am trying to solve, go to: http://bugs.mysql.com/bug.php?id=10641 )I have narrowed down the issue, and I have a solution. But I cannot recreate the issue on a test environment so I can test my solution.
Here is my code:
public static void main(String[] args) {
System.out.println("Programm Starting");
int numberOfthreads = 2;
for(int x = 1; x <= numberOfthreads; x++){
//Create the object UpdateClass
// Create the Runable object
Runnable r = new Runnable() {
// Start the Runnable
public void run() {
System.out.println("Running");
}
};
Thread thr = new Thread(r);
System.out.println("Thread object created");
thr.start();
final UpdateClass session = new UpdateClass(x);
System.out.println("Thread object started");
try {
System.out.println("Starting UpdateClass.runProcess()");
session.runProcess();
Thread.sleep(1);
}
catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
thr.stop();
System.out.println("Thread stopped");
}
}
Basically, I am trying to replicate simultaneous UPDATEs to the MySql table to create the LockWait Timeout issue.
My class UpdateClass works the way I need it to, but I cannot recreate the simultaneous events to call the class.
Question: How can I alter my code to increase the probability of generating the conditions that lead to the timeout?

Answer 1

few things you could try to replicate the issue in test:
change the innodb_lock_wait_timeout in the mysqlcnf to a small time interval or increase the thread sleep time (if you change the cnf file, you will need to restart the DB server)
Ensure that you are holding onto a lock (and have not released it) before the thread goes to sleep (you could possibly achieve the same with a network disconnect/DB connection going down while the lock has not been released but not entirely certain about that).
I am assuming that your MySQL version is the same as in production.