Defines the fields used for result collapsing.

The collapsing fields are sequences of metadata class characters separated by commas. The characters $ and # are special metadata class characters for result collapsing, representing document summary text and document URL respectively. Commas are used to separate columns which can be selected at query time using the appropriate query processor option.

Setting the key

Set this configuration key in the search package or data source configuration.

Use the configuration key editor to add or edit the indexing.collapse_fields key, and set the value. This can be set to any valid String value.

Default value

Results are collapsed by their summary text by default:



Generate 2 signatures per document: Column 0 is the normal document signature and column 1 is a signature derived from the concatenation of metadata fields t and a in that order:



  • When t is used as the collapsing field, collapsing will apply for the actual value of the t metadata, which may be different from the document title. The best way to understand the differences is to display both the result title, and the value of the t metadata next to each other (Using the JSON or XML endpoint and the &SM=meta&SF=[t] CGI parameters). Usually, t will be multi-valued as the default metadata mapping maps it to different title fields and HTML h1-h4 headers.