Sunday, November 19, 2006

What's wrong with this graph?

So I am currently working on a MySQL server that is showing behavior as depicted in the following graph.

There can be several possible reasons for these sudden drops. I am working on the issue and will be posting the results. Have you experienced something similar?

1 comment:

Sheeri said...

There's something really wrong with the graph -- it looks as if threads connected is the same as threads created....isn't that the point of the thread cache, that new ones aren't created?

It does make sense that the # of threads cached goes down when threads created goes up.

The question is why aren't the cached threads being used?

And why do queries per second go down -- is it because things get slow, or because fewer people are connecting? If it's fewer people connecting maybe the app or whatever doesn't see a need to use threads from the cache?

So I'd want to see other things plotted -- I'd guess you're in heavy heavy load or very little load during those times.