Maintain Facet count after faceting

Question

I'm using Sitecore 9.3 and Solr 8.1.1. I'm developing a search filter using Sitecore Content Search API, with the behavior of keeping the facet count the same even after selecting options.

For example, if the filter have these options :

• Option 1 , count = 11
• Option 2 , count = 20
• Option 3 , count = 8

If I select Option 1, other options' count will change according to this selection.

I don't want that, I want to maintain the count as it is in the same Solr query. At the same time, I have multiple filters, so I want to keep the count for only the options in the selected filter, while other filters count can be changed.

Answer 1

Solr provides Tagging and Excluding Filters functionality to support facets for multi-select fields. It allows to tag a part of filter query and then exclude the tagged part when counting facets for a specific field.

Sitecore Content Search provider currently does not support tag and ex parameters and does not have any Linq extension methods for passing them to Solr.

There is a good example of how to prepare and apply these parameters by extending Sitecore Content Search query with SolrNet QueryOptions in the question Sitecore Solr multiple filter tagging / excluding.

However, if you want to solve this by using only out-of-the-box Content Search API, be prepared to perform N+1 requests to Solr (where N is the number of multi-select filters with at least one option selected):

1. Request with all filters applied to get valid results.
2. Request without conditions from the first multi-select filter to get facets for this filter options.
3. Request without conditions from the second multi-select filter, and so on until you process all multi-select filters.