Databricks Updated Databricks-Generative-AI-Engineer-Associate Exam Questions and Answers by jayce

The problem describes a Retrieval-Augmented Generation (RAG) system for HR policy Q&A where responses are incomplete and unstructured due to the retriever failing to return sufficient context. The engineer has already tried different embedding and response-generating LLMs without success, suggesting the issue lies in the retrieval process—specifically, how documents are chunked and indexed. Let’s evaluate the options.

Option A: Add the section header as a prefix to chunks

Adding section headers provides additional context to each chunk, helping the retriever understand the chunk’s relevance within the document structure (e.g., “Leave Policy: Annual Leave” vs. just “Annual Leave”). This can improve retrieval precision for structured HR policies.

Databricks Reference:"Metadata, such as section headers, can be appended to chunks to enhance retrieval accuracy in RAG systems"("Databricks Generative AI Cookbook," 2023).

Option B: Increase the document chunk size

Larger chunks include more context per retrieval, reducing the chance of missing relevant information split across smaller chunks. For structured HR policies, this can ensure entire sections or rules are retrieved together.

Databricks Reference:"Increasing chunk size can improve context completeness, though it may trade off with retrieval specificity"("Building LLM Applications with Databricks").

Option C: Split the document by sentence

Splitting by sentence creates very small chunks, which could exacerbate the problem by fragmenting context further. This is likely why the current system fails—it retrieves incomplete snippets rather than cohesive policy sections.

Databricks Reference: No specific extract opposes this, but the emphasis on context completeness in RAG suggests smaller chunks worsen incomplete responses.

Option D: Use a larger embedding model

A larger embedding model might improve vector quality, but the question states that experimenting with different embedding models didn’t help. This suggests the issue isn’t embedding quality but rather chunking/retrieval strategy.

Databricks Reference: Embedding models are critical, but not the focus when retrieval context is the bottleneck.

Option E: Fine tune the response generation model

Fine-tuning the LLM could improve response coherence, but if the retriever doesn’t provide complete context, the LLM can’t generate full answers. The root issue is retrieval, not generation.

Databricks Reference: Fine-tuning is recommended for domain-specific generation, not retrieval fixes ("Generative AI Engineer Guide").

Conclusion: Options A and B address the retrieval issue directly by enhancing chunk context—either through metadata (A) or size (B)—aligning with Databricks’ RAG optimization strategies. C would worsen the problem, while D and E don’t target the root cause given prior experimentation.

Problem Context: The engineer needs an efficient way to store chunks of unstructured documents to facilitate easy retrieval and search. The current dataframe consists of document filenames and associated text chunks.

Explanation of Options:

Option A: Splitting into train and test sets is more relevant for model training scenarios and not directly applicable to storage for retrieval in a Vector Search index.

Option B: Flattening the dataframe such that each row contains a single chunk with a unique identifier is the most performant for storage and retrieval. This structure aligns well with how data is indexed and queried in vector search applications, making it easier to retrieve specific chunks efficiently.

Option C: Creating a unique identifier for each document only does not address the need to access individual chunks efficiently, which is critical in a Vector Search application.

Option D: Storing each chunk as an independent JSON file creates unnecessary overhead and complexity in managing and querying large volumes of files.

OptionBis the most efficient and practical approach, allowing for streamlined indexing and retrieval processes in a Delta table environment, fitting the requirements of a Vector Search index.

To design an LLM-based application that can answer employee HR questions using HR PDF documentation, the most effective approach is option D. Here's why:

Chunking and Vector Store Embedding:HR documentation tends to be lengthy, so splitting it into smaller, manageable chunks helps optimize retrieval. These chunks are then embedded into avector store(a database that stores vector representations of text). Each chunk of text is transformed into anembeddingusing a transformer-based model, which allows for efficient similarity-based retrieval.

Using Vector Search for Retrieval:When an employee asks a question, the system converts their query into an embedding as well. This embedding is then compared with the embeddings of the document chunks in the vector store. The most semantically similar chunks are retrieved, which ensures that the answer is based on the most relevant parts of the documentation.

LLM to Generate a Response:Once the relevant chunks are retrieved, these chunks are passed into the LLM, which uses them as context to generate a coherent and accurate response to the employee's question.

Why Other Options Are Less Suitable:

A (Calculate Averaged Embeddings): Averaging embeddings might dilute important information. It doesn't provide enough granularity to focus on specific sections of documents.

B (Summarize HR Documentation): Summarization loses the detail necessary for HR-related queries, which are often specific. It would likely miss the mark for more detailed inquiries.

C (Interaction Matrix and ALS): This approach is better suited for recommendation systems and not for HR queries, as it’s focused on collaborative filtering rather than text-based retrieval.

Thus, option D is the most effective solution for providing precise and contextual answers based on HR documentation.