Knowing how to kill a transaction is not important. Until it is really important.

VIEW ACTIVE TRANSACTIONS

There are many reasons to visit the "All Active Transactions" module in ServiceNow. Taking a casual glance is usually not the reason.

Why would you want to view all transaction?

Something is not right. You sense trouble.
You KNOW there is something wrong.

How to view active transactions

If high security is enabled, elevate privileges to security_admin. Might not applicable in Helsinki.
Using the Left Navigation Bar, Navigate to User Administration > Active Transactions.

Kill a transaction

ServiceNow doesn't really bleed I guess.

After viewing the list, there is a transaction you want to stop. Why would you have a reason for killing a transaction?

Someone you now dislike created an infinite loop in the code
Something important is being deleted at a rapid pace
A job is taking forever, most likely an integration

HOW TO KILL A TRANSACTION

If high security is enabled, elevate privileges to security_admin. Might not applicable in Helsinki.
Using the Left Navigation Bar, Navigate to User Administration > Active Transactions.
Select the transaction you want to stop.
Either right-click on the record and select Kill, or select the check box next the to record and select Kill from the Actions on selected rows drop-down at the bottom of the list.

Transaction Not Found

If you can't find the transaction, but you know it is still running, you can contact HI Support. They can help you kill the job.

Have you no patience and want to kill it yourself? There is another way to track it down.

Determine available nodes

Your ServiceNow instance has multiple nodes. The transaction might on a different node. You have to be logged on to the correct node to see it. First you have to find out how many nodes you have.