LLM Apps in Production (RAG + Vector DB + Caching) · Lesson

Batching and Asynchronous Operations

Implement batch processing for embedding generation and asynchronous calls to LLM APIs to enhance throughput.

Batching and Asynchronous Operations is a free LLM Apps in Production (RAG + Vector DB + Caching) lesson on CoddyKit — lesson 2 of 4. You can read the complete lesson below for free — then practise it hands-on in the browser with a built-in code editor and a 24/7 AI tutor. It is part of the LLM Apps in Production (RAG + Vector DB + Caching) learning path, one of 4 lessons in the course, and your progress syncs across the web and the CoddyKit app.

Boosting RAG Performance

Your RAG application is working, but is it fast and cost-effective? As user traffic grows, you'll need to optimize how your app interacts with LLMs and vector databases.

In this lesson, we'll explore two powerful techniques: batching and asynchronous operations. These can significantly improve your RAG system's throughput and reduce operational costs.

One Task at a Time

Imagine you have a list of documents, and you need to get embeddings for each one. In a synchronous approach, your program would process each document one by one.

It sends a request for Document 1.
It waits for the embedding to return.
Then, it sends a request for Document 2.
It waits again.

This "wait-and-process" model is simple but can be very slow, especially with many I/O operations like API calls.

Doing Things in Parallel

Asynchronous operations allow your program to send multiple requests without waiting for each one to complete before starting the next. Think of it like a restaurant manager taking multiple orders before any food is ready.

Send request for Document 1.
Immediately send request for Document 2.
Immediately send request for Document 3.
Collect results as they become available.

This approach keeps your program busy, leading to much faster overall completion times for many tasks.

How Async Works (Conceptual)

While the exact implementation varies by language, the core idea is to avoid blocking your main program thread. For example, in Java, you might use CompletableFuture to manage tasks that run in the background.

Here's a conceptual look at how you might call an LLM API asynchronously:

// Conceptual Async Call
CompletableFuture<String> futureResponse1 = llmApi.generateAsync("prompt 1");
CompletableFuture<String> futureResponse2 = llmApi.generateAsync("prompt 2");

// Do other work while responses are being generated

// Get results when ready
String response1 = futureResponse1.join();
String response2 = futureResponse2.join();

This allows your application to perform other computations while waiting for I/O-bound LLM responses.

Grouping for Efficiency

Batching is the strategy of grouping several individual items or requests into a single, larger request. Many LLM providers and embedding services support batching.

Instead of 10 separate API calls for 10 documents, make 1 API call for a "batch" of 10 documents.
This reduces the overhead of establishing connections and processing each request individually.
It can also be more cost-effective as some APIs charge less per token for batched requests.

Why Batch Embeddings?

Generating vector embeddings for documents is a perfect use case for batching. When you load a large dataset, you'll have many text chunks that need to be converted into vectors.

Sending these in batches to your embedding model API means:

Fewer API calls: Reduced network latency and overhead.
Higher throughput: Process more text in the same amount of time.
Potential cost savings: Some APIs offer better pricing for larger batches.

Batching Embeddings Code

Let's see how to implement a simple batching mechanism for embedding generation. We'll simulate an embedding service that takes a list of texts.

This example processes a list of documents in chunks (batches) to send to an embedding service. Notice how we group documents before calling the mock service.

public class Main {
  // Simulate an embedding client
  static class MockEmbeddingClient {
    public double[][] getEmbeddings(String[] texts) {
      System.out.println("Processing batch of " + texts.length + " texts...");
      // Simulate network latency
      try {
        Thread.sleep(100 * texts.length); // Slower for larger batches
      } catch (InterruptedException e) {
        Thread.currentThread().interrupt();
      }
      double[][] embeddings = new double[texts.length][3]; // 3D for simplicity
      for (int i = 0; i < texts.length; i++) {
        embeddings[i][0] = texts[i].length() * 0.1;
        embeddings[i][1] = texts[i].hashCode() % 100;
        embeddings[i][2] = i;
      }
      return embeddings;
    }
  }

  public static void main(String[] args) {
    MockEmbeddingClient client = new MockEmbeddingClient();
    String[] documents = {
      "The quick brown fox jumps over the lazy dog.",
      "Never underestimate the power of a good book.",
      "Artificial intelligence is transforming industries.",
      "Retrieval Augmented Generation enhances LLM accuracy.",
      "Batching improves efficiency for embedding calls.",
      "Asynchronous operations prevent blocking.",
      "CoddyKit makes learning fun and interactive.",
      "Optimizing RAG saves costs and boosts speed."
    };

    int batchSize = 3;
    for (int i = 0; i < documents.length; i += batchSize) {
      int endIndex = Math.min(i + batchSize, documents.length);
      String[] currentBatch = new String[endIndex - i];
      System.arraycopy(documents, i, currentBatch, 0, endIndex - i);

      double[][] batchEmbeddings = client.getEmbeddings(currentBatch);
      System.out.println("Received " + batchEmbeddings.length + " embeddings for this batch.");
      // In a real app, you'd store these embeddings in a vector database
    }
    System.out.println("All documents processed in batches.");
  }
}

Async + Batching = Super RAG

The real power comes from combining both techniques. You can make asynchronous calls to batched requests.

Group your documents into batches.
Send each batch request to the API asynchronously.
Your program can then manage multiple concurrent batch requests, maximizing throughput.

This is crucial for ingesting massive amounts of data or handling high-volume real-time embedding lookups.

Batching & Async Pitfalls

While powerful, batching and async operations require careful handling:

API Rate Limits: Don't send too many requests too quickly, even if they're batched. Respect API limits.
Memory Usage: Very large batches can consume significant memory. Find an optimal batch size.
Error Handling: If one item in a batch fails, how do you handle it? Design robust error recovery.
Latency vs. Throughput: Async improves throughput, but might not reduce the latency of a single request.

Optimize Your Workflow

You're working on a RAG application that needs to process thousands of customer reviews to generate embeddings for a vector database. Which strategies would be most effective to improve the efficiency and speed of this data ingestion process?

Summary: Faster, Cheaper RAG

Great job! You've learned how to supercharge your RAG system's performance and cost-efficiency.

Asynchronous operations allow concurrent processing, reducing overall wait times for I/O-bound tasks.
Batching groups multiple small requests into larger ones, cutting down on API overhead and potentially saving costs.
Combining both techniques provides the most powerful optimization for high-volume data processing in RAG.

These strategies are essential for building scalable and robust LLM applications in production.

Frequently asked questions

Is the “Batching and Asynchronous Operations” lesson free?

Yes — the full text of “Batching and Asynchronous Operations” is free to read here on the web, and the LLM Apps in Production (RAG + Vector DB + Caching) course includes 4 lessons in total. To practise it interactively (a built-in code editor and a 24/7 AI tutor) and unlock the rest of the LLM Apps in Production (RAG + Vector DB + Caching) course, upgrade to CoddyKit PRO.

What will I learn in “Batching and Asynchronous Operations”?

Implement batch processing for embedding generation and asynchronous calls to LLM APIs to enhance throughput. You practise LLM Apps in Production (RAG + Vector DB + Caching) with hands-on code you run directly in the browser, and a 24/7 AI tutor answers your questions as you work through the lesson.

Do I need any experience to start LLM Apps in Production (RAG + Vector DB + Caching)?

No prior experience is required. LLM Apps in Production (RAG + Vector DB + Caching) on CoddyKit is structured for beginners through advanced learners; this is — lesson 2 of 4, so you can start here or from the beginning and move at your own pace.

How long does the “Batching and Asynchronous Operations” lesson take?

Most CoddyKit lessons take about 5–10 minutes. Each one is bite-sized and interactive, so you make steady progress and pick up exactly where you left off across the web and the app.

Can I write and run code in this LLM Apps in Production (RAG + Vector DB + Caching) lesson?

Yes. Every LLM Apps in Production (RAG + Vector DB + Caching) lesson includes a built-in code editor, so you write and run real code right in your browser and get instant AI feedback — no local setup required.

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