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Aniket Hingane
Aniket Hingane

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Advanced Multi-Stage, Multi-Vector Querying Using the ColBERT Approach in Qdrant

Smart Retrieval → Brilliant Answering → Elevating AI Performance

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First, Let’s Understand The Basics.
To set the stage for a deeper exploration, let’s first grasp the essential fundamentals.

Multi-Stage
Imagine you’re looking for a book in a huge library. Instead of checking every single book, you first look at the section names to narrow it down. Then, you look more closely at the books in that section. This two-step process is like multi-stage searching in AI. It’s faster and more efficient than looking at everything in detail right away.

When searching for accurate results, larger vector representations work better but are costly. To address this, the general practice in the industry is to use a multi-stage approach:

Initial Filtering: Use a smaller, less expensive vector representation to generate a large list of potential candidates.
Refined Scoring: Re-score these candidates using a larger, more accurate vector representation.
Here are a few ways to implement this two-stage search architecture:

Quantized Vectors: Begin with simplified vectors and then refine with detailed ones.
Matryoshka Representation Learning (MRL): Use short vectors first, then enhance with longer vectors for better precision.
Dense Vectors: Initially filter with standard dense vectors, and then fine-tune the results with a sophisticated multi-vector model like

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ColBERT.
Multi-Vector
Think of this like describing a person using multiple characteristics instead of just one. In AI, we use multiple “vectors” (sets of numbers) to represent complex information more accurately. It’s like using height, hair color, and eye color to describe someone instead of just their name.

In multi-vector retrieval, multiple vectors are used to improve the accuracy and relevance of search results. Here’s a straightforward breakdown of the concept:

Multiple Representations: Instead of using a single vector, multiple vectors represent different aspects of the data.
Comprehensive Matching: These vectors capture various features, leading to more comprehensive and relevant search results.
Here’s how it works:

Aspect-Based Vectors: Create vectors that focus on different attributes or aspects of the data, enhancing the search’s depth.
Layered Retrieval: Use multiple layers of vectors, each capturing different levels of detail, to refine the search results progressively.
Combination Models: Combine results from different vectors to get a final, more accurate result.
This approach ensures that the search is not only thorough but also more precise, capturing nuances that a single vector might miss.

ColBERT
ColBERT is a clever way to search. It’s like having a super-efficient librarian who can quickly find the most relevant books for you. ColBERT looks at both your question and the information it has in a special way that makes searching faster and more accurate.

It stands for “Contextualized Late Interaction over BERT.” It is a model from Stanford University that enhances the deep language understanding of BERT with a unique way of handling information retrieval called late interaction. Let me simplify here and we’ll take a deeper look later:

Separate Processing: ColBERT processes queries and documents separately until the final stage, making it both efficient and precise.
Deep Language Understanding: It uses BERT, a powerful language model, to understand context deeply.
There are two versions of ColBERT:

ColBERT (First Version): Developed by Omar Khattab and Matei Zaharia, this version introduced the late interaction method for effective passage search. Their work was published in 2020.
ColBERTv2 (Second Version): An improved version created by Omar Khattab, Barlas Oguz, Matei Zaharia, and Michael S. Bernstein. Presented in 2021, it made the model more effective and efficient by adding features like denoised supervision and residual compression.
In short, ColBERT and ColBERTv2 are models designed to improve search accuracy and efficiency by using advanced language processing and innovative interaction techniques.

Qdrant
Qdrant is designed to store and quickly find information that’s represented as vectors (those number sets we talked about earlier). Qdrant helps make searching through lots of vector data really fast.

Qdrant allows you to store, search, and manage these vectors, along with extra information called payloads. These payloads help you refine your searches and provide useful details to your users.

To start using Qdrant:

Use the Python qdrant-client. (qdrant-client lib)
Install Qdrant by getting its latest Docker image and connecting to it on your own computer.
Or, try Qdrant’s free Cloud option until you’re ready to use it more extensively.
Why Adopt the ColBERT Approach with Qdrant?
The multi-stage multi-vector querying with ColBERT Approach in Qdrant offers significant benefits for information retrieval from vector databases. By breaking down the search process into stages and using multiple vectors to represent both queries and documents, this method achieves a level of nuance and accuracy that surpasses simpler retrieval techniques. It excels at handling complex, context-dependent queries, allowing users to find relevant information even when their questions are intricate or multifaceted.

This approach is particularly valuable when dealing with large-scale databases, as it efficiently narrows down the search space in initial stages before conducting more detailed comparisons.

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