Context:
I have two separate search clusters:
- ElasticSearch (version 7.16)
- Opensearch (version 2.11)
Each cluster indexes content from one or more Content Management Systems (CMS). There's some overlap in the content between the clusters, but mostly the content is different (altough the same 'subject').
Objective
I need to get a unified search result from both clusters. I'll perform (almost) the same query. The goal is to ensure that the result scoring maintains relevance and consistency across the combined results.
Challenges
Directly matching scores between clusters may not be feasible as the unique content in both clusters will affect search relevance.
Question(s)
What are the recommended approaches for achieving a unified search across multiple clusters? (if even possible, research showed me: No)
If the answer to this is: None
Could it be possible on server, query or post search level? Is there any way to combine results with scoring relevance post-search? As in simply: Combine result arrays, apply calculation on the scoring to make them related.