topic Re: How to evaluate an arithmetic difference between two consecutive events in Splunk Search

How to evaluate an arithmetic difference between two consecutive events

rootto — Wed, 08 Sep 2010 21:40:14 GMT

Hi all,

I would like to evaluate the difference between two events (in theory the events contain completely different data). Let's say I have the following events:

timestap1 81 115 42683 1267 0 0
timestap2 81 107 42683 1267 0 0

the third column corresponds to the field Total_Sent and I want to raise an alert if the field is not growing. How can I do: Toal_Sent1 - Total_Sent2 (in my case 42683 - 42683) and check if the result is greater than 5 ?

Thanks from a splunk newbie

Re: How to evaluate an arithmetic difference between two consecutive events

dwaddle — Wed, 08 Sep 2010 21:50:13 GMT

Have you tried the "delta" search operator?

http://www.splunk.com/base/Documentation/latest/SearchReference/Delta

Delta will find the different between the same extracted field in consecutive events. You will probably need to define field extractions for your fields in order to be able to use delta against them.

Re: How to evaluate an arithmetic difference between two consecutive events

rootto — Wed, 08 Sep 2010 23:35:00 GMT

Thanks I implemented it doing

| delta Total_Sent AS diffsent | search diffsent > 5

and it works. Do you know if I can limit the search to the last two events? I tried to pipe | head 2 | but it doesn't help.

Thanks again

Re: How to evaluate an arithmetic difference between two consecutive events

alanden_splunk — Tue, 24 Jan 2017 19:52:33 GMT

The last two results (after diffsent>5 filter) would look like:

| delta Total_Sent AS diffsent | search diffsent > 5 | head 2

The last two events would look like this:

| head 2 | delta Total_Sent AS diffsent | search diffsent > 5