Is it true that arahants don't have sati? A couple of months ago someone tried to convince me that arahants no longer have sati.

He said that sati is like a raft in the sense that it should be given up as soon as the goal, arahantship, has been reached. To give more strength to his claim he also pointed out that sati is not one of the 10 parami (perfections).

I myself think that his claim is absurd, I think that arahants have nothing but sati. But, I'm neither a scholar nor an arahant. So, I can be wrong. I also don't understand the link he makes to the 10 parami.

Does someone have a reference or source from the tipitaka that would support or deny his claim without a doubt and put my mind at ease? And does someone understand the link he makes to the perfections?
He said that sati is like a raft in the sense that it should be given up as soon as the goal, arahantship, has been reached.


Sati is "non-forgetting" of the Dhamma Truth. 


  To give more strength to his claim he also pointed out that sati is not one of the 10 parami (perfections).


This does not make sense because effort, determination, patience, etc are parami. Why would a mind that has destroyed/uprooted the defilements need effort, determination, patience, etc? Regardless, the Buddha never taught the 10 parami; particularly for Arahants.


  I myself think that his claim is absurd, I think that arahants have nothing but sati.


When the defilements are destroyed/uprooted; naturally the sati of a non-arahant (which includes the abandoning of wrong view) is not required. The sati of a non-arahant or learner is described as follows:


  One is mindful to abandon wrong view &amp; to enter &amp; remain in right view: This is one's right mindfulness.
  
  MN 117


This being said, the mind of an arahant obviously cannot forget the Dhamma Truth. Thus MN 117 also says:


  Thus the learner is endowed with eight factors, and the arahant with ten.
  
  MN 117


In short, the sati of an arahant is automatic because an arahant can never forget the Dhamma Truth.