A Stored Parameters collection contains lists of parameters, where each list is has a unique identifier called a “key”. These lists of parameters can be plugged into Fusion query pipelines. The Stored Parameters facility provides a mapping layer between the keys and specific actions carried during search and is somewhat similar to database triggers or stored procedures. The use for this collection is to store Solr facet parameters for a particular document or product category, where the facet parameters are stored as a JSON object. An example of what the input JSON is shown in a section below. A Stored Parameters collection is an auxiliary Fusion collection which is associated with a primary collection via naming conventions: for a primary collection, the name of the associated Stored Parameters collection consists of the name of the primary collection plus the suffix “_stored_parameters”. In the Fusion UI, Stored Parameter collections are not displayed in the list of collections in the Collections Admin panel, nor are there controls on the UI for creating or populating these collections; all collection administration is done via calls to the REST API.

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Stored Parameters for Facets

  • An existing facets configuration can be converted into the required format via a once-off custom script (e.g. written by Lucidworks solution engineers or by a customer’s technical team).
  • Note that if a caller wants particular behavior e.g. specifying that all results should be from a given category, then it is up to them to specify that in their original request (e.g. using a filter query “fq” setting).
  • A new Stored Parameter Query Stage can then be used in a query pipeline to add the required parameters for a given key (e.g. a category ID).

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Stored Parameters Example

The following example shows how faceting can be carried out over a hierarchy of categories and subcategories where there are many known subcategory-specific attributes to query on. The example data is taken from the Best Buy product catalog data. In this list of stored parameter objects, the set of fields used are:
  • “id” : record ID (or “key” in the sense of a “Key-Value” store) of the category to facet on.
  • “label_s” : human-readable label for this record, i.e., the category name
  • “in_ids_ss” : parent categories, if an intermediate category in a category hierarchy. Intended use is in traversing a directed graph of categories.
  • “out_ids_ss” : child categories, if an intermediate category in a category hierarchy. Intended use is in traversing a directed graph of categories.
  • “parameters_ss” : list of arbitrary Solr parameters that can be used to construct a query that is relevant for the entity described by this record. In this example, it is the list of facet parameters to use for this specific category.
[
    {"id": "abcat0600000",
      "label_s": "Movies & Music",
      "in_ids_ss": ["cat00000"],
      "out_ids_ss": ["cat02001", "cat02015"] },
    { "id": "cat02001",
      "label_s": "Music",
      "in_ids_ss": ["abcat0600000"],
      "out_ids_ss": ["cat02673", "cat02012", "cat02004"] },
    { "id": "cat02010",
      "label_s": "Rock",
      "in_ids_ss": ["cat02001"],
      "out_ids_ss": ["cat02673", "cat02687", "cat02661", "cat02662", "cat02675", "cat02678", "cat02680"],
      "parameters_ss": ["facet.field=attr_format_", "facet.field=attr_albumLabel_", "facet.field=attr_genre_"] },
    { "id": "cat02673",
      "label_s": "Hard Rock",
      "in_ids_ss": ["cat02010"],
      "parameters_ss": ["facet.field=attr_format_", "facet.field=attr_albumLabel_", "facet.field=attr_genre_"] },
    { "id": "abcat0208001",
      "label_s": "Batteries" },
    { "id": "abcat0208002",
      "label_s": "Alkaline Batteries",
      "in_ids_ss": ["abcat0208001"],
      "parameters_ss": ["facet.field=attr_hardGoodType_"] }
]

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Direct Access and Navigation

A caller can query the COLLECTION_NAME_stored_parameters system collection directly. For example, a Solr request to get the human-readable label stored in field “label_s” for a specific category ID is: 
`http://127.0.0.1:8983/solr/COLLECTION_NAME_stored_parameters/query?q=id:<category_id>&fl=label_s`
Direct access allows for navigation up and down a hierarchy of categories by listing incoming and outgoing links that specify a category’s location. For example, the Solr requests to find the parent(s) and children of a given category, respectively, are: 
`http://127.0.0.1:8983/solr/COLLECTION_NAME_stored_parameters/query?q=id:<category_id>&fl=in_ids_ss`
`http://127.0.0.1:8983/solr/COLLECTION_NAME_stored_parameters/query?q=id:<category_id>&fl=out_ids_ss`
Note that this kind of “graph navigation” can become inefficient if it requires submitting a large number of queries to navigate up and down the hierarchy.