There is no MDEX Engine configuration required to enable wildcard search. If wildcarding is enabled in Developer Studio, the MDEX Engine automatically enables the use of the asterisk operator (*) in appropriate search queries.

The following considerations apply to wildcard search queries that contain punctuation, such as abc*.d*f:

The MDEX Engine rejects and does not process queries that contain only wildcard characters and punctuation or spaces, such as *., * *. Queries with wildcards only are also rejected.

The maximum number of matching terms for a wildcard expression is 100 by default. You can modify this value with the --wildcard_max flag for the dgraph.

If a search query includes a wildcard expression that matches too many terms, the search returns results for the top frequent terms and the is_valid flag is set to false in the record search report.

To retrieve the error message, use the ESearchReport.getErrorMessage() method (Java), or ESearchReport.ErrorMessage property (.NET).

In case of wildcard search with punctuation, you may want to increase --wildcard_max, if you would like to increase the number of returned matched results. For more information about tuning this parameter, see the MDEX Engine Performance Tuning Guide.

Other flags or attributes that existed in previous releases for tuning wildcard search are deprecated starting with the version 6.1.2 and ignored by the MDEX Engine.