Adding CPUs puts MySQL 5.5 (Debian) performance down

Solution 1:

Not to burst anyone's bubble of guesses, but this is a bug in MySQL 5.5.

Solution 2:

Well its a really leading question without first knowing something about the architecture that you are running.. but generally there is an exponential hit upon bus throughput when adding CPU capacity especially architecture that supports multiple multi core processors, just stop and think for a moment of the implications upon the interrupt cycle across whatever bus bandwidth limitation deployed.... in any event of performance... understanding that your architecture will either bottle neck I/O or Bits Per Cycle, again keep in mind that multiple cpu's need multiple threading.. so no matter the speed of your FSB... if you've hardware is only 64bit then the physical electrical connectivity is going to have to share this limitation across as many cores in the same clock cycle... now stop and think of the positive implications of upgrading from a 64bit to a 256bit system board you may get x3 times better throughput at full tilt given that x1 will be spent upon threading/maintaining the operation overhead.. however during normal operations you may experience an uncomfortable reality about the overhead when you only need a single processor/operator.. I guess its a balancing act or more specifically the right horse for the right course.. Steveo Reedo [email protected]