Although regular expressions are a powerful way to set Splunk AppDynamics configurations, you should consider the following to avoid performance issues:

• Do not use wildcard expressions unless absolutely needed. You do not need to use wildcard expressions (.*) before or after a match, and each wildcard regular expression results in approximately an order of magnitude performance impact.
• The number of configurations, the frequency the configuration is applied, and the content length of the target string: For example, if the configuration using a regular expression is applied in many places at high frequency for longer target strings, you might consider reducing the usage of the configuration or decrease the frequency of its application.