Configure the Index for Similarity Queries

This section describes how to index and process signature values to be able to enter similarity queries in the Search API and calculate similarity measures.

This task shows you how to:

See Also
Use the #attrsimilar Function in the Search API
Code Samples to Create Similarity Query Prefix Handlers

Configure the Data Model and the Data Processing

The following procedure explains how to store a signature in an index field represented by the SIGNATURE_INDEX_FIELD variable.

Note: If you need to store multiple signatures, use a dynamic field. To do so, follow step 2 and in the field Advanced options, select the Multivalued and Store meta names properties.

  1. In the Administration Console, go to Index > Data Model > Advanced Schema .
  2. Add a SIGNATURE_INDEX_FIELD to store signature values.
    1. Click Add field .
    2. Enter a name, for example, my_signature_bin and set the type to Binary.
    3. Set the new field as RAM-based for performance reasons.
  3. Go to Index > Data Processing > Analysis pipeline > Document Processors.
  4. Add a SimilarStringToPart document processor for part conversion to the pipeline, and in Input from, enter the name of the SIGNATURE_INPUT_META containing all values of the signature vector, for example, my_signature_meta.

    This document processor can:

    • Parse signature values and convert them into binary blob ready to use by the index.
    • Delete the meta to create a part with the same name.

  5. In the Mappings tab, create the mapping between the SIGNATURE_INPUT_META and the SIGNATURE_INDEX_FIELD.
    1. Add a mapping source. Give it a name, for example, my_signature_meta and set its type to Part.
    2. Add the SIGNATURE_INDEX_FIELD as mapping target. For example, target the my_signature_bin index field.
  6. Click Apply.