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From:Jorge Bastos Date:October 23 2012 12:49pm
Subject:RE: mysql threads too high
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Tal,

Not a MySQL issue,
Which application is using MySQL? It seems that it's with a problem left'n
unclosed and/or unnecessary connections.

> 
> is anyone have some idea?
> 
> MySql crash when we getting to 1200 threads!!
> 
> PLEASE HELP!
> 
> Tal.
> ________________________________________
> From: Tal Ben-Gal [tal@stripped]
> Sent: 12 October 2012 09:07
> To: Shawn Green; win32@stripped
> Subject: RE: mysql threads too high
> 
> 1) Reduce the connection to 1500, now no one after 300 connection can
> log in
> 2) Mysql use max of 1GB the server has 12GB
> 3) unfortunately it is not possible at this time to rewrite the
> application that run on 5000 PC and in 5 location, all other location
> working fin I only have this problem in one location with 500 users.
> 
> So NO, your suggestions (good once) did not resolve the problem.
> 
> Tal.
> 
> 
> ________________________________________
> From: Shawn Green [shawn.l.green@stripped]
> Sent: 11 October 2012 15:36
> To: win32@stripped
> Subject: Re: mysql threads too high
> 
> On 10/11/2012 10:07 AM, Tal Ben-Gal wrote:
> > Thanks, I try to change it but it made no different, after 1250 mysql
> threads, no one can connect to the database.
> >
> > In the new ini:
> > max_connections=3510
> > myisam_max_sort_file_size=25G
> >
> 
> You have to realize that once you overload your system with RAM
> requests and start to use the page file, that all those activities that
> used to be operating at RAM speed are now operating at DISK speed.
> That's a performance reduction on the scale of 100x to 10000x slower
> than before.
> 
> There are several ways to fix this:
> 
> 1) Start refusing connections once you reach a number that causes your
> system to begin using swap (system paging file). You control this by
> configuring a reasonable value for --max-connections (Hint: unless you
> have several hundred gigabytes of RAM in this one machine, 3510 is not
> a reasonable value)
> 
> 2) Adjust your memory allocation settings to something more reasonable.
> Remember, some values are allocated once for the entire server (global)
> and some are per thread (local). You must multiply the number of local
> allocations by the number of active threads you allow (max_connections)
> in order to get an upper-limit estimate of RAM usage just for your
> threads.  Add that to your global allocations to get an upper estimate
> of how much RAM you will use in total.
> 
> 3) Fix your queries. If they ran faster, you would be able to handle
> more queries every second. For example, if you start a query every .5
> seconds and each of them takes an average of 1s to compute then you
> will need a lot of connections as all of your queries are overlapping.
> If you can reduce your average execution time to something less than .5
> seconds (say in the .1 second range) then you can handle at least 500%
> more queries every second than you had before you tuned your queries.
> You will need at least 10x fewer connections than you did under the
> original scenario.
> 
> All of these points (and more) are covered in the MySQL manual:
> http://dev.mysql.com/doc/refman/5.5/en/optimization.html
> 
> --
> Shawn Green
> MySQL Principal Technical Support Engineer Oracle USA, Inc. - Hardware
> and Software, Engineered to Work Together.
> Office: Blountville, TN
> 
> 
> 
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> 
> This e-mail message is intended to be received only by persons entitled
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> 
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> This e-mail message is intended to be received only by persons entitled
> to receive the confidential information it may contain. E-mail messages
> to clients of ben-gal.net may contain information that is confidential
> and legally privileged. Please do not read, copy, forward, or store
> this message unless you are an intended recipient of it. If you have
> received this message in error, please forward it to the sender and
> delete it completely from your computer system. For more information
> please e-mail tal@stripped This e-mail message is intended to be
> received only by persons entitled to receive the confidential
> information it may contain. E-mail messages to clients of ben-gal.net
> may contain information that is confidential and legally privileged.
> Please do not read, copy, forward, or store this message unless you are
> an intended recipient of it. If you have received this message in
> error, please forward it to the sender and delete it completely from
> your computer system. For more information please e-mail tal@ben-
> gal.net
> 
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Thread
mysql threads too highTal Ben-Gal11 Oct
  • Re: mysql threads too highAndrĂ©s Tello11 Oct
    • RE: mysql threads too highTal Ben-Gal11 Oct
      • Re: mysql threads too highShawn Green11 Oct
        • RE: mysql threads too highTal Ben-Gal12 Oct
          • RE: mysql threads too highTal Ben-Gal23 Oct
            • RE: mysql threads too highJorge Bastos23 Oct
              • RE: mysql threads too highTal Ben-Gal23 Oct
                • Re: mysql threads too highShawn Green23 Oct
                  • RE: mysql threads too highTal Ben-Gal23 Oct
                    • Re: mysql threads too highShawn Green23 Oct
                      • RE: mysql threads too highTal Ben-Gal23 Oct
                        • RE: mysql threads too highTal Ben-Gal24 Oct