Explanation
By default, the CIM data models search all indexes in Splunk Enterprise Security. This means that any event that matches the tags and fields of a data model can be included in the data model, regardless of the index where it is stored. However, this can also affect the performance and efficiency of the data model searches, especially if there are many indexes that do not contain relevant data for the data model. Therefore, it is recommended to use the indexes allow list setting in the CIM add-on to constrain the indexes that each data model searches. The indexes allow list is a comma-separated list of indexes that you want to include in the data model search. You can specify index names or index macros. For example, you can set the indexes allow list for the Authentication data model to index=main, index=security, index=auth to limit the search to only those three indexes12. References = 1: Managing data models in Enterprise Security - Splunk Lantern - Indexes allow list. 2: Overview of the Splunk Common Information Model - Splunk Documentation - Why the CIM exists.