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.