Description:
Is there any upper limit to set the value for ACO parameter "MaxSessionCacheSize"?
Solution:
No. The limit will be the one of the amount of memory available on the OS itself.
You may estimate the amount of needed memory by technote:
TEC506685
https://support.ca.com/irj/portal/anonymous/redirArticles?reqPage=search&searchID=TEC506685
Be aware that there could be performances issues depending of the available memory and the value you set to that parameter. You need to benchmark it before on your machine.