Advanced Filter Caching is a relatively new feature in Solr, available in version 3.4 and above. It allows precise control over how Solr handles filter queries in order to maximize performance, including the ability to specify if a filter is cached, the order filters are evaluated, and post filtering.

Filter Queries in Solr

Adding a filter expressed as a query to a Solr request is a snap… simply add an additional fq parameter for each …

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Result Grouping, also called Field Collapsing, has been committed to Solr!
This functionality limits the number of documents for each “group”, usually defined by the unique values in a field (just like field faceting).

You can think of it like faceted search, except instead of just getting a count, you get the top documents for that constraint or category. There are tons of potential use cases:

• For web search, only show 1 or

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