Merge pull request #258708 from HeidiSteen/heidist-fix

filter clarification

Author: prmerger-automator[bot]

articles/search/hybrid-search-how-to-query.md

@@ -196,6 +196,10 @@ api-key: {{admin-api-key}}
 
 + The filter mode can affect the number of results available to the semantic reranker. As a best practice, it's smart to give the semantic ranker the maximum number of documents (50). If prefilters or postfilters are too selective, you might be underserving the semantic ranker by giving it fewer than 50 documents to work with.
 
++ Prefiltering is applied before query execution. If prefilter reduces the search area to 100 documents, the vector query executes over the "contentVector" field for those 100 documents, returning the k=50 best matches. Those 50 matching documents then pass to RRF for merged results, and then to semantic ranker.
+
++ Postfilter is applied after query execution. If k=50 returns 50 matches on the vector query side, then the post-filter is applied to the 50 matches, reducing results that meet filter criteria, leaving you with fewer than 50 documents to pass to semantic ranker
+
 ## Configure a query response
 
 When you're setting up the hybrid query, think about the response structure. The response is a flattened rowset. Parameters on the query determine which fields are in each row and how many rows are in the response. The search engine ranks the matching documents and returns the most relevant results.