**Note: Bringing back some posts from the dead in hopes to help future customers! This is for those who searched K2HostServer high CPU or the like.**

Sometimes designing looping line rules results in high CPU and slow performance for K2 tools. When a loop occurs, the entire history of a process can be loaded from the database; with each new the loop, new history is saved into the database with increasing bytes. If you have a significant number of process instances (for ex: 20 or 100), you may see the resulting CPU spike. 

It is a good idea to not include a loop in a process instance. This is especially true if the loop is occuring frequently (e.g. every 60 seconds). 

If this may be your case, take a look at the K2 Blackpearl Best Practice documentation found here: http://help.k2.com/KB000352 

Refer to page 21 "LINE RULES (TRY TO KEEP MAINTENANCE ON LOW) where it notes the following:

"Be careful not to design looping line rules. Don’t create a polling activity that loops back on itself every few minutes to check if a certain condition on an external system has been met. Building this type of functionality into a K2 process can add significant load on the K2 server and databases. If you need to do something like this use an asynchronous server event.."

Hi,

Perhaps, adding more RAM would help (link below):

http://help.k2.com/helppages/K2blackpearlICG4.6.8/webframe.html#Prereqs_Hardware.html

K2 recommends to have at least 8GB of RAM

---------------------------

K2 Server

• 
  
• 4 GB min
  
• 8 GB recommended (especially if 64 bit servers are used)
  

Thanks