The Dynamic Role refresh rate, which determines the rate at which the table containing the list of users is refreshed when set to zero would impact on the K2 Server’s performance. 

Error Scenario

The Dynamic role refresh rate value is set in seconds. When set to 5, for example the refresh rate would be every five seconds. To improve performance that value could be lowered. However, if that value were set to zero, this would not imply a null or no refresh rate. This meant that the refresh rate would be continuous and ongoing.
Further implications of a 0 value would be that the Table would effectively be locked preventing any additional activity on that database table. The Dynamic Role feature would then not function as the roles associated with destination users for example, could not be updated dynamically.

Error Messages

No specific error message may or would occur when this takes place, however the K2 Server’s performance would be affected and the

Error Resolution

This feature has been enhanced to force a minimum value of 5 seconds whether the Dynamic Role feature is disabled or enabled. Any value <5 will automatically be changed to 5 seconds. This will prevent and disallow a 0 value for the Dynamic Role refresh rate. 

This issue has been resolved in the latest K2 4.5 Update KB001420 (4.10060.1.1420)