How to Fine-tune Search Engine Relevancy

 

About

This functionality provides the ability to dynamically select which search engines are targeted by the current query.

  • This is useful if you need to target different search engines based on a set of criteria.

  • For example, if a query targets a set of search engines, but you need to change this set because the current user does not have access to the set targeted by the query.

  • The identity of the current user is just one possible criteria that can be used to decide which search engines to query.

Limitations

  • Some SmartHub Features are unsupported by some search engines.

  • For information about limitations to your search engine, see the "Limitations" topic for your search engine

Select the Search Engines to Query (via Scripting Stage)

You achieve this by using a Query Scripting Tuning stage added at the General level (not on each search engine). 

  • Query.SelectedBackends is a List<string> property which you can modify based on your own criteria.

It contains the search engine names that the current query targets.

Steps to configure:

  1. Open the SmartHub Administration page at http(s)://<web-app-url>/_admin.
  2. Click the General Settings link on the left side navigation.
  3. Under USER EXPERIENCE TUNING click ADD QUERY TUNING
  4. Select Query Scripting Processor and give it a name (ex: "search engine Selector")
  5. Inside the Code Editor modify the Query.SelectedBackends property using any List<string> operations.
    Initially, this list contains all the search engine names targeted by the page where the query was triggered. 

Example

  • Assume 3 search engines are configured in SmartHub:
    • SharePoint Online
    • NetDocuments
    • RightFind
  • The page query targets all search engines using the FederatorBackends:"*" syntax in the query template.

  • You want to remove RightFind search engine if the current user is from "Department=X."
    You would achieve this by:

    Copy 
    //code to detect if the user is from Department X goes here and initializes bool userIsFromDepartmentX

    if (userIsFromDepartmentX) {
        Query.SelectedBackends.Remove("RightFind"); // the initial SelectedBackends list contains the items SPO, NetDocs, RightFind
    }

Boost the Document Score Dynamically Based on the Search Engine Name

This functionality gives you the ability to increase (or decrease) the document score (Rank) if the document comes from a specific search engine.

  • This enables you to change the position of the document in the final result set.

You achieve this by using a Query Scripting Stage added at the General level (not on each search engine).

Query Rank Boosting Property

  • Query.RankBoostingSpecification is a property that enables you to specify the boost based on the search engine name.

  • It accepts a set of rules called "specifications" which define what search engine needs boosting and the boost amounts. 

Syntax and Parameters

A boost specification has the following format: PropertyName,PropertyValue,Multiplier,Addition

  • PropertyName: This is the property name which defines the search engine name. Set this value as <Search Engine Name>
  • PropertyValue: This is the search engine name. For example: "SPO".
  • Multiplier; This is a float number which shows the value that is multiplied with the original score. If the multiplier=1 the score is not changed.
    • A value greater than 1 increases the score.
    • A value lower than 1 decreases the score.
  • Addition: This is a float number which shows the value that is added to the original score.
  •  If addition=0 the score will not be changed.
    • A value greater than 0 increases the score.
    • A value lower than 0 decreases the score.

Basic Operations

Query.RankBoostingSpecification supports the following basic operations:

  • Initialization
    • Initializes the property by using an object constructor.
    • Notice that multiple specs are separated by the ";" character.
      Example: 
      Copy
      Query.RankBoostingSpecification = new RankBoostingSpecification("BackendName,SPO,2,10;BackendName,RightFind,0.1,0");
  • Add a new boost specification
    • Add a new condition for boosting based on backend name.
    • You don't need to call the constructor first.
      Example
      • Query.RankBoostingSpecification.Add("BackendName,NetDocs,2,-10");
  • Remove a boost specification
    • Remove a previously added boost specification.
      Example:
      • Query.RankBoostingSpecification.Remove("BackendName,NetDocs,2,-10");

Example for Basic Usage

  • Assume you are increasing the SharePoint Online backend scores by doubling them and subtracting 10.
  • A document with an initial score of 50 would end up with a score of 90.
Copy 
Query.RankBoostingSpecification.Add("BackendName,SPO,2,-10");

For more advanced usage scenarios you can use the underlying strongly typed object model.

RankBoostingSpecification.BoostSpecs property is a List<FieldBoostSpecification> which holds an item for each boost specification.

FieldBoostSpecification class has the following properties:

  • public string Field;
  • public string Value;
  • public double BoostMultiplier;
  • public double BoostAddition;

FieldBoostSpecification has a constructor which accepts a boost specification in a string format and deserializes it for you.

Example:

Copy 
new FieldBoostSpecification("BackendName,SPO,2,10");

Example for Advanced Usage

  • Assume you have a previous stage which affects the score for the SPO backend but you don't know the exact multiplier or addition which were used.
  • You want to remove only those specific boost specifications
Copy 
Query.RankBoostingSpecification.BoostSpecs.RemoveAll(x => x.Field == "BackendName" && x.Value == "SPO");