Key cache usage statistics

[Johan De Meersman]

Hi,

I'm writing a stats script that monitors, among other things, the MyISAM key
cache usage. As per the mysql.com docs, I plot Key_blocks_used as the
high-watermark line, but on some of my servers, this is quite a bit lower
than current usage.

Googling reveals that I'm not the only one to see this, but no-one seems to
know what's up with that.

Could someone provide me with MySQL's definition of "high-watermark" ? :-)

Thx,
Johan

-- 
Celsius is based on water temperature.
Fahrenheit is based on alcohol temperature.
Ergo, Fahrenheit is better than Celsius. QED.