By default, when matches are found for session attribute searches, the Portal also queries the Canisters where the matching sessions are stored for additional session information. This information includes the list of events, browser information, domain location, and other useful information about the visitor and the session.
Depending on the number of users in your environment and other performance factors, this additional querying of the Canister may significantly impact performance of session search and session retrieval.
Optionally, you can disable this additional querying of the Canisters. When disabled, the returned search results contain only the information that's stored in the cxReveal database. These fields include the available columns for cxReveal search templates, as well as sufficient information to locate and replay the session stored in the Canister.
The setting to disable is
Use Canister Data for Database Search