Comments for Yuriy Zisin http://www.yzisin.com/blog Development as a lifestyle Sun, 28 Mar 2010 15:16:00 +0000 http://wordpress.org/?v=2.9.2 hourly 1 Comment on Application semaphores using MySQL by Yuriy Zisin http://www.yzisin.com/blog/?p=9&cpage=1#comment-139 Yuriy Zisin Sun, 28 Mar 2010 15:16:00 +0000 http://www.yzisin.com/blog/?p=9#comment-139 Yes, I wrote it from my personal experience. I usually use it in cronjobs to guarantee that I run only single script instance. Yes, I wrote it from my personal experience. I usually use it in cronjobs to guarantee that I run only single script instance.

]]> Comment on Application semaphores using MySQL by youngie http://www.yzisin.com/blog/?p=9&cpage=1#comment-134 youngie Sat, 13 Mar 2010 10:55:12 +0000 http://www.yzisin.com/blog/?p=9#comment-134 You have tested it and writing form your personal experience or you find some information online? You have tested it and writing form your personal experience or you find some information online?

]]> Comment on Application semaphores using MySQL by Yuriy Zisin http://www.yzisin.com/blog/?p=9&cpage=1#comment-50 Yuriy Zisin Thu, 20 Aug 2009 08:24:09 +0000 http://www.yzisin.com/blog/?p=9#comment-50 Agree, but the next paragraph on the same page tells: >>> This function can be used to implement application locks or to simulate record locks. Names are locked on a server-wide basis. If a name has been locked by one client, GET_LOCK() blocks any request by another client for a lock with the same name. This allows clients that agree on a given lock name to use the name to perform cooperative advisory locking. <<< I have successfully used it in cronjobs to prevent multiple job instances running at the same time. I added a notice. Thank you for warning. Agree, but the next paragraph on the same page tells:
>>>

This function can be used to implement application locks or to simulate record locks. Names are locked on a server-wide basis. If a name has been locked by one client, GET_LOCK() blocks any request by another client for a lock with the same name. This allows clients that agree on a given lock name to use the name to perform cooperative advisory locking.

<<<

I have successfully used it in cronjobs to prevent multiple job instances running at the same time.

I added a notice. Thank you for warning.

]]> Comment on Application semaphores using MySQL by D http://www.yzisin.com/blog/?p=9&cpage=1#comment-49 D Thu, 20 Aug 2009 03:04:39 +0000 http://www.yzisin.com/blog/?p=9#comment-49 # GET_LOCK will fail if a lock with specified name already set and script can stop; -no it will not. what makes you to be 100% sure... from http://dev.mysql.com/doc/refman/5.0/en/miscellaneous-functions.html#function_get-lock: *If you have a lock obtained with GET_LOCK(), it is released when you execute RELEASE_LOCK(), !!!!execute a new GET_LOCK()!!!!, or your connection terminates (either normally or abnormally). # GET_LOCK will fail if a lock with specified name already set and script can stop; -no it will not. what makes you to be 100% sure…

from http://dev.mysql.com/doc/refman/5.0/en/miscellaneous-functions.html#function_get-lock:
*If you have a lock obtained with GET_LOCK(), it is released when you execute RELEASE_LOCK(), !!!!execute a new GET_LOCK()!!!!, or your connection terminates (either normally or abnormally).

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