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From:Shawn Green Date:October 23 2012 6:23pm
Subject:Re: mysql threads too high
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On 10/23/2012 1:13 PM, Tal Ben-Gal wrote:
> If I turn the pooling off the connection going up the roof, none stay sleep, I have
> about 40 queries per min for each connection, its take long time to open the connection,
> some of the queries are very complex and involve lots of join and some on 2 different
> databases.
>
> Opening one connection at the time (and close it - yes with .close - it been tried.)
> is not an option, as it is slowing the application drastically.
> It is windows base application, there is no 'block' of quires, users can't go any
> farther until the query finish, furthermore some queries are background work that need to
> update the user screen every 5 Min.
>
> The application been tested with all the option you suggested and the best solution
> is with pooling, the application running in 4 locations, no problem on 3 of them
> Only one location having this problem. The one we have the problem is the most
> powerful server 12GB memory and 12 core CPU.
> This application is for the NHS and lots of testing done on it to see the best
> solution, and it is running on 2 locations (about 300 users in each) with no problem.
> The location that having this problem is actually the one with fewer users, only
> 180.
>
> The My.ini is identical in all location, the application identical in all location.
>
> Could it be the server too fast??!!
>
> No, changing the application now can't be done - it will require NHS approval all
> over again - it is running fine on 3 locations.
>

That kind of throughput reduction is nearly always hardware based. As 
your code has not changed, your MySQL version is not any different, your 
query patterns are alike, and your configurations are probably very 
similar, then that leaves the hardware as the next logical place to look.

You asked "Could it be the server too fast??!!" This machine wouldn't 
happen to be using the NUMA architecture, would it? If so, the way it 
maps our memory allocations may be creating a HUGE volume of cross-zone 
access requirements. The solution would be to break your MySQL data down 
into pieces that require less cross-talk between memory zones or get 
some hardware that is not NUMA-based.

As a test, put it on a reasonably powerful Linux box and see how that 
handles the load.

This post represents the limit of free advice I can give on this topic.

Yours,
-- 
Shawn Green
MySQL Principal Technical Support Engineer
Oracle USA, Inc. - Hardware and Software, Engineered to Work Together.
Office: Blountville, TN


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