The exact module groups results into three strata based on how well they match the query string:
The highest stratum contains results whose complete text matches the user’s query exactly.
The middle stratum contains results that contain the user’s query but are not an exact match.
The lowest stratum contains all other types of matches, such as matches that would not be matches without synonyms.
The exact module can optionally be specified with the considerFieldRanks parameter, as follows:
exact(considerFieldRanks)
Specifying this parameter causes the exact module to sort records according to their priorities in your search interface after it has sorted them according to its own criteria.
Important: The exact module is computationally expensive, especially on large text fields. It is intended for use only on small text fields (such as dimension values or small property values such as part IDs). Use of this module in these cases will result in very poor performance and/or application failures due to request timeouts. The phrase module, with and without approximation turned on, does similar but less complex ranking that can be used as a higher performance substitute.
