How to merge results from two vectorStore queries into one prompt context?

[marcelodl]

Hello everyone, I need some guidance.

I’m using a vectorStore and want to build a prompt that includes two distinct contexts, both retrieved from the vector store, for example:

Given the context below:
-----------------
<context1>   // result set #1 from vectorStore (e.g., filter A / topK1)
-----------------

Write a document using the model below:
-----------------
<context2>   // result set #2 from vectorStore (e.g., filter B / topK2)
-----------------

I’m currently using QuestionAnswerAdvisory like this:

chatClient.prompt()
    .advisors(advisorSpec -> advisorSpec
        .param(CONVERSATION_ID, id))
    .param(TOP_K, 100)
    .param(QuestionAnswerAdvisor.FILTER_EXPRESSION, "key == '" + key + "'")
;

What’s the recommended Spring AI pattern to run two separate vectorStore queries (with different filters/topK) and inject both result sets into a single prompt?

• Is it possible to attach two QuestionAnswerAdvisors (one per filter) and have them both contribute to the final context?
• Or should I run two queries manually (pre-prompt), then pass them as separate variables/sections in the prompt template (e.g., <context1> and <context2>) via prompt().param(...)?

Any code snippet or best practice for merging multiple retrievals into one prompt would be greatly appreciated. Thanks!

[gengzi]

The official documentation of Spring AI states that VectorStoreDocumentRetriever allows for direct retrieval from the vector repository. You can create different vector retrievers and merge the results with ConcatenationDocumentJoiner

https://docs.spring.io/spring-ai/reference/api/retrieval-augmented-generation.html