Explanation
Ref:
https://docs.oracle.com/en/cloud/saas/project-portfolio-management/19a/fapfm/implementing-project-execution- Topic - Submitting the Process to Maintain Project Resource Search Index: Procedure Submit the Maintain Project Resource Search Index job set to update the resources that appear on the Search and Evaluate Resources page when a resource manager searches for resources to fulfill project resource requests. The job set consists of a set of processes that facilitate efficient and rapid searches for qualified resources.
Resource managers can't search for resources or view resource details if the search index isn't available for a project resource request with qualifications or keywords. For project resource requests without qualifications and keywords, resource managers can search for and evaluate resources based on resource availability even if the search index isn't current or available.
Caution: The search index isn't available if the Maintain Project Resource Search Index job set process fails, or while the process is running.