basic question

[richieasir]

What is 'high water mark'?

thanks in adv.

 

[TomBascom]

It is the highest value that a metric has reached since you began measuring it.

The term is a reference to the marks that periodic floods make on buildings (or landscapes).

In the Progress world the two most common high water marks are the amount of space used in a storage area and the number of locks used in the lock table. The current value is often less than both the maximum value and the largest value that has been seen. It is useful to know all 3 (current, maximum and "high water") in order to judge whether or not you need to do something like increase (or decrease) -L or add an extent to a storage area.

 

[richieasir]

but high water mark is also defined as 'a pointer to the last formatted block within the DB storage area.'

what is this 'last formatted block'

thanks in adv.

 

[TomBascom]

That is the same thing as what I meant by "the amount of space used in a storage area". It is what it says that it is -- the last block that has been formatted within the storage area. Blocks higher than that have only been allocated from the OS, they have not been "formatted" by Progress to contain data. The formatting process involves writing headers into the blocks. Gory details are probably in an Exchange presentation or two from Rich Banville sometime in the last few years. You can search PSDN for them.