Perrin Harkins wrote:
On Mon, Sep 20, 2010 at 7:00 PM, Vincent Veyron <vv.li...@wanadoo.fr> wrote:
When I use this new machine (it is currently disabled), my registered
users on occasion will retrieve the data from the demo account instead
of their own, as if the children spawned by the two apache2 processes
got mixed up.
Are these just two virtual servers running from the same httpd.conf
and server binaries? How does each one know which database to use?
It seems unlikely that this is related to your processor change.
I would be more nuanced.
Sometimes, a problem in the logic, which was there all the time but never caused any
actual problem because it was very unlikely, can become acute because of an apparently
unrelated change.
For example, events that almost never occurred "simultaneously" on a slower processor or
with less memory, now start to happen "simultaneously" because the processor is much
faster, or because there is more memory available to start more processes at the same time.
And never mind the fact that a modern 64-bit processor is likely to have several cores,
allowing it to actually run more than one process at the same time.
So something which before never happened, or happened only once or twice a year, and was
not reproducible and thus was ignored as a "cosmic ray hitting the CPU", now happens 2 or
3 times a day and cannot be ignored anymore.
The original description of the problem really makes me think of something like
that.
I would bet my shirt that if you considered 2 instances of this application side by side,
and imagined that they do each step in parallel, there would be a point where you would
notice that something could go wrong.
And with a faster CPU, things that can go wrong, do go wrong faster.
