The following dictionary attributes either affect the way Zing indexes tables or ranks search results.

Index and search dictionary attributes

Zing uses dictionary attributes set at the table or field level to configure the following settings:
  • indexing behavior
  • ranking of search results
  • the BM25 relevancy ranking algorithm

no_text_index

For Customer Service and Support guidelines on setting the no_text_index option for different field types, see KB0859922 on the Now Support site.

text_index_scorer_bm25_b

This dictionary attribute is part of the BM25 algorithm. The attribute impacts the importance of the length of a document in search results. If this attribute is 0, the length has no bearing. In this case, a document of two words would be valued equally as a document with 1000 words. Very short documents are often weighted lower than longer documents. The default is 0.75.

text_index_scorer_bm25_k1

This dictionary attribute is part of the BM25 algorithm. The attribute helps determine term frequency saturation characteristics, that is, having the search term appear in a document increases the relevancy of the document, but the increase is less impactful as the numbers climb. For example, a search term occurring 10 times in a document makes it more relevant than a document that has only one occurrence. However, a document that has 100 occurrences of the search term may not be ten times more impactful than a document that has 10 occurrences. The relevance approaches a maximum effect asymptote. The higher the attribute value, the lower the maximum effect of multiple occurrences. Typical values are between 1.25 - 2.0.