About approximate matching

The approximate setting is appropriate in cases where the runtime performance of the standard Phrase module is inadequate because of large result contents and/or high site load.

Approximate matching provides higher-performance matching, as compared to the standard Phrase module, with somewhat less exact results. With approximate matching enabled, the Phrase module looks at a limited number of positions in each result that a phrase match could possibly exist, rather than all the positions. Only this limited number of possible occurrences is considered, regardless of whether there are later occurrences that are better, more relevant matches.

Enabling positional indexing increases the number of occurrences that the Phrase module looks at, thereby increasing the accuracy of the approximate phrase matching results. See Using positional indexing with the Phrase module for more information.