NOTES FOR MYSQL PMDA
====================

Chosen philosophy
-----------------

As you may notice, I have chosen to not implement multiple
servers to be monitored by one instance of PMDA. The reasons
are folowing:

- You usually do not run multiple MySQL servers on one computer.
- If you run multiple MySQL servers on multiple computers, you
probably want to monitor other things on this computer too - like
processor/memory usage, which cannot be monitored remotely.
- It is much simplier when you monitor only one server.
- Monitoring of processes (see below)

Monitoring of processes
-----------------------

I would like to make it possible to see the MySQL processes (show processlist)
too. Processes would be instances. If the PMDA were monitoring multiple
servers, we would require two-dimensional instance space which is currently
missing.

Monitoring of processes is not finished yet since I am thinking of a way how
to implement it to be quick and simple.

Performance
-----------

To be fast, mysql PMDA asks server for status/variables only once per
every fetch call, stores the result and then uses stored values. But
many programs (like pminfo) fetch multiple times. So maybe it would
help to use results not only for that specific set, but for whole second
(i.e., have timestamp in seconds and get new status from server only when
time differs).

