执行PHP操作后网站关闭

Question

Say I have a website hosted on a remote server. I navigate to a page on this website and attempt to perform a specific action (the details of which I can go into more depth if necessary, but for the time being let me just say that the action involves running a program on the server with data obtained from a database.)

The page just continually loads. So, I attempt to navigate to the main website. That now continually loads without resolve as well. After about a day the website comes back, so perhaps there is some automated process that kills tasks after a certain time has passed. My question is this:

Am I able to kill this task or perform any action to allow me to navigate to the website without waiting a full day? I can go into more detail if necessary.

Thanks.

By request, some more in-depth information.

The PHP script retrieves text-based information from the database. Based on this information the PHP script calls an executable program. The output from the executable is output to the screen.

I've checked mysql processlist and found a process that took a particularly long time. I killed it, so it may be that the executable is continually running. If so, how would I go about determining this, and if not is there anything else it could potentially be? Thanks.

Solved : Alright, so basically Mike Purcell's advice which was to show the process list of mysql processes and kill any ones that I saw that took a substantially long time. Once that was done, it was just a matter of restarting mysql and httpd. Thanks again to everyone who commented.

Answer 1

Sounds like that mysterious action may have caused an un-optimized query to be executed, which may cause other queries to hang until the bad query has finished executing. If you have access to the mysql server via terminal you could issue the following commands to kill the long running query:

mysql> show processlist;

This command will output any currently running queries. Pay attention to the time column, this will display the time in seconds of how long a query has been executing. In theory you should never have any queries running past a few seconds, but some queries may take upwards of 10 minutes depending on the query and the dataset involved. The other column to note is the id column, with this value you can kill a query manually (much like killing a process on a linux machine).

mysql> kill 387 # 387 is just an example

Now when you run the show processlist command again, that query should disappear from the process list.

Answer 2

Looks like you DoS'ed your own website!

Maybe this webpage shouldn't be a webpage, but a task performed manually or via cron? Else, anyone will be able to find this page and kill your website when they want...

If this program need so much resources, you should limit it somehow : try to optimize it, try to limit the resources allowed to it (I don't know how to do that, I just know it's possible :s )

If the problem is already here, you can try to kill the process ( ps aux | grep <processname" , then kill -9 processid ), or the query if the problems comes from MySQL (inside your mysql client, show processis t; then kill <query n°> ). Try the SQL first.

Answer 3

If the site is locked because of an intensive MySQL process, or a MySQL process gone rogue, the best thing you could do is isolate the process to its own database thread so normal tables don't get locked.

Other option is to switch some of your databases from (assuming) MyISAM to the InnoDB engine, if that can work. Batch insertions will be slower and performance signature will vary, but, you won't be subjected to such severe locking.