Problem with user parameter item and .last(0)

[mbobkiewicz]

Hi,
I´m running Zabbix 1.4.1. On the linux client I´ve added the postfix user parameter items as mentioned in the Cookbook forum. But I don´t want just the total values but also the differences between the last two values. I have an item "postsendk" returning the the total bytes send. But I also want to know how much bytes where send during the last 5 minutes. So I created an item postsendk.last(0) which doesn´t work, I also have tested postsendk[].last(0) without success. Both forms return "Incorrect key format 'key_name[param1,param2,...]'" when I try to save the item.
On the other hand the item vfs.file.size[/var/log/messages].last(0) works on the same box. Doesn´t zabbix support this with user parameter items? Does the item had to be one receiving parameters?
Any suggestions are welcome,

Mike

[Alexei]

Wait, wait, wait! Something is wrong here. Functions like last(0) must be used in trigger expressions, not as part of item keys!

[mbobkiewicz]

Hi Alexei,
that´s what the manual say, but some users will always find the hidden features ;-). The main problem is that you can´t use the same item description twice. So if you want to have both the total and the delta of an item be displayed you´re in trouble. So I was really happy to find the .last(0) way. Now I can see the total use of a network interface and the use per minute. Will you now kill this or maybe think about a different way, something like the option to save two values for an item?