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Ingesting a Dataset into LanceDB

In this tutorial, you will ingest a dataset from Huggingface into your LanceDB Cloud table. For interactive code, check out the Python Notebook or the TypeScript Example

Prerequisites

You will connect to a remote LanceDB cluster, ingest data and run some searches. Before you start, make sure you sign up for LanceDB Cloud and get your API key and cluster URI.

1. Installation

Install the LanceDB SDK with your preferred language.

pip install lancedb datasets

npm install @lancedb/lancedb

2. Connect to LanceDB

For LanceDB Cloud users, the database URI (which starts with db://) and API key can both be retrieved from the LanceDB Cloud UI. For step-by-step instructions, refer to our onboarding tutorial.

For LanceDB Enterprise users, please contact our team to obtain your database URI, API key, and host_override URL.

import lancedb
import numpy as np
import pyarrow as pa
import os

# Connect to LanceDB Cloud/Enterprise
uri = "db://your-database-uri"
api_key = "your-api-key"
region = "us-east-1"

# (Optional) For LanceDB Enterprise, set the host override to your enterprise endpoint
host_override = os.environ.get("LANCEDB_HOST_OVERRIDE")

db = lancedb.connect(
  uri=uri,
  api_key=api_key,
  region=region,
  host_override=host_override
)

import { connect, Index, Table } from '@lancedb/lancedb';
import { FixedSizeList, Field, Float32, Schema, Utf8 } from 'apache-arrow';

// Connect to LanceDB Cloud/Enterprise
const dbUri = process.env.LANCEDB_URI || 'db://your-database-uri';
const apiKey = process.env.LANCEDB_API_KEY;
const region = process.env.LANCEDB_REGION;

// (Optional) For LanceDB Enterprise, set the host override to your enterprise endpoint
const hostOverride = process.env.LANCEDB_HOST_OVERRIDE;

const db = await connect(dbUri, { 
  apiKey,
  region,
  hostOverride
});

3. Load Dataset

For large datasets, the operation should be performed in batches to optimize memory usage. Let's see how it looks when we try to load a larger dataset.

from datasets import load_dataset

# Load a sample dataset from HuggingFace with pre-computed embeddings
sample_dataset = load_dataset("sunhaozhepy/ag_news_sbert_keywords_embeddings", split="test[:1000]")
print(f"Loaded {len(sample_dataset)} samples")
print(f"Sample features: {sample_dataset.features}")
print(f"Column names: {sample_dataset.column_names}")

# Preview the first sample
print(sample_dataset[0])

# Get embedding dimension
vector_dim = len(sample_dataset[0]["keywords_embeddings"])
print(f"Embedding dimension: {vector_dim}")

const BATCH_SIZE = 100; // HF API default limit
const POLL_INTERVAL = 10000; // 10 seconds
const MAX_RETRIES = 5;
const INITIAL_RETRY_DELAY = 1000; // 1 second

interface Document {
    text: string;
    label: number;
    keywords: string[];
    embeddings?: number[];
    [key: string]: unknown;
}

interface HfDatasetResponse {
    rows: {
        row: {
            text: string;
            label: number;
            keywords: string[];
            keywords_embeddings?: number[];
        };
    }[];
}

/**
 * Loads documents from the Hugging Face dataset API in batches
 */
async function loadDataset(datasetName: string, split: string = 'train', targetSize: number = 1000, offset: number = 0): Promise<Document[]> {    
    try {
        console.log('Fetching dataset...');
        const batches = Math.ceil(targetSize / BATCH_SIZE);
        let allDocuments: Document[] = [];
        const hfToken = process.env.HF_TOKEN; // Optional Hugging Face token

        for (let i = 0; i < batches; i++) {
            const offset = i * BATCH_SIZE;
            const url = `https://datasets-server.huggingface.co/rows?dataset=${datasetName}&config=default&split=${split}&offset=${offset}&limit=${BATCH_SIZE}`;
            console.log(`Fetching batch ${i + 1}/${batches} from offset ${offset}...`);

            // Add retry logic with exponential backoff
            let retries = 0;
            let success = false;
            let data: HfDatasetResponse | null = null;

            while (!success && retries < MAX_RETRIES) {
                try {
                    const headers: HeadersInit = {
                        'Content-Type': 'application/json',
                    };

                    // Add authorization header if token is available
                    if (hfToken) {
                        headers['Authorization'] = `Bearer ${hfToken}`;
                    }

                    const fetchOptions = {
                        method: 'GET',
                        headers,
                        timeout: 30000, // 30 second timeout
                    };

                    const response = await fetch(url, fetchOptions);
                    if (!response.ok) {
                        const errorText = await response.text();
                        console.error(`Error response (attempt ${retries + 1}):`, errorText);
                        throw new Error(`HTTP error! status: ${response.status}, body: ${errorText}`);
                    }

                    data = JSON.parse(await response.text()) as HfDatasetResponse;
                    if (!data.rows) {
                        throw new Error('No rows found in response');
                    }

                    success = true;
                } catch (error) {
                    retries++;
                    if (retries >= MAX_RETRIES) {
                        console.error(`Failed after ${MAX_RETRIES} retries:`, error);
                        throw error;
                    }

                    const delay = INITIAL_RETRY_DELAY * Math.pow(2, retries - 1);
                    console.log(`Retry ${retries}/${MAX_RETRIES} after ${delay}ms...`);
                    await new Promise(resolve => setTimeout(resolve, delay));
                }
            }

            // Ensure data is defined before using it
            if (!data || !data.rows) {
                throw new Error('No data received after retries');
            }

            console.log(`Received ${data.rows.length} rows in batch ${i + 1}`);
            const documents = data.rows.map(({ row }) => ({
                text: row.text,
                label: row.label,
                keywords: row.keywords,
                embeddings: row.keywords_embeddings
            }));
            allDocuments = allDocuments.concat(documents);

            if (data.rows.length < BATCH_SIZE) {
                console.log('Reached end of dataset');
                break;
            }
        }

        console.log(`Total documents loaded: ${allDocuments.length}`);
        return allDocuments;
    } catch (error) {
        console.error("Failed to load dataset:", error);
        throw error;
    }
}

// Load dataset
console.log('Loading AG News dataset...');
const datasetName = "sunhaozhepy/ag_news_sbert_keywords_embeddings";
const split = "test";
const targetSize = 1000;
const sampleData = await loadDataset(datasetName, split, targetSize);
console.log(`Loaded ${sampleData.length} examples from AG News dataset`);

4. Ingest Data

import pyarrow as pa

# Create a table with the dataset
table_name = "lancedb-cloud-quickstart"
table = db.create_table(table_name, data=sample_dataset, mode="overwrite")

# Convert list to fixedsizelist on the vector column
table.alter_columns(dict(path="keywords_embeddings", data_type=pa.list_(pa.float32(), vector_dim)))
print(f"Table '{table_name}' created successfully")

const tableName = "lancedb-cloud-quickstart";

const dataWithEmbeddings: Document[] = sampleData;
const firstDocWithEmbedding = dataWithEmbeddings.find((doc: Document) => 
    (doc.embeddings && Array.isArray(doc.embeddings) && doc.embeddings.length > 0));

if (!firstDocWithEmbedding || !firstDocWithEmbedding.embeddings || !Array.isArray(firstDocWithEmbedding.embeddings)) {
    throw new Error('No document with valid embeddings found in the dataset. Please check if keywords_embeddings field exists.');
}
const embeddingDimension = firstDocWithEmbedding.embeddings.length;

// Create schema
const schema = new Schema([
    new Field('text', new Utf8(), true),
    new Field('label', new Float32(), true),
    new Field('keywords', new Utf8(), true),
    new Field('embeddings', new FixedSizeList(embeddingDimension, new Field('item', new Float32(), true)), true)
]);

// Create table with data
const table = await db.createTable(tableName, dataWithEmbeddings, { 
    schema,
    mode: "overwrite" 
});
console.log('Successfully created table');

5. Build an Index

After creating a table with vector data, you'll want to create an index to enable fast similarity searches. The index creation process optimizes the data structure for efficient vector similarity lookups, significantly improving query performance for large datasets.

Note

As opposed to LanceDB OSS, the create_index/createIndex operation executes asynchronously in LanceDB Cloud/Enterprise. To ensure the index is fully built, you can use the wait_timeout parameter or call wait_for_index on the table.

from datetime import timedelta

# Create a vector index and wait for it to complete
table.create_index("cosine", vector_column_name="keywords_embeddings", wait_timeout=timedelta(seconds=120))
print(table.index_stats("keywords_embeddings_idx"))

// Create a vector index
await table.createIndex("embeddings", {
config: Index.ivfPq({
    distanceType: "cosine",
}),
});

// Wait for the index to be ready
const indexName = "embeddings_idx";
await table.waitForIndex([indexName], 120);
console.log(await table.indexStats(indexName));

Once you have created and indexed your table, you can perform vector similarity searches. LanceDB provides a flexible search API that allows you to find similar vectors, apply filters, and select specific columns to return. The examples below demonstrate basic vector searches as well as filtered searches that combine vector similarity with traditional SQL-style filtering.

query_dataset = load_dataset("sunhaozhepy/ag_news_sbert_keywords_embeddings", split="test[5000:5001]")
print(f"Query keywords: {query_dataset[0]['keywords']}")
query_embed = query_dataset["keywords_embeddings"][0]

# A vector search
result = (
    table.search(query_embed)
    .select(["text", "keywords", "label"])
    .limit(5)
    .to_pandas()
)
print("Search results:")
print(result)

// Perform semantic search with a new query
const queryDocs = await loadDataset(datasetName, split, 1, targetSize);
if (queryDocs.length === 0) {
    throw new Error("Failed to load a query document");
}
const queryDoc = queryDocs[0];
if (!queryDoc.embeddings || !Array.isArray(queryDoc.embeddings)) {
    throw new Error("Query document doesn't have a valid embedding after processing");
}
const results = await table.search(queryDoc.embeddings)
    .limit(5)
    .select(['text','keywords','label'])
    .toArray();

console.log('Search Results:');
console.log(results);

Add filter to your vector search query. Your can use SQL statements, like where for filtering.

filtered_result = (
    table.search(query_embed)
    .where("label > 2")
    .select(["text", "keywords", "label"])
    .limit(5)
    .to_pandas()
)
print("Filtered search results (label > 2):")
print(filtered_result)

const filteredResultsesults = await table.search(queryDoc.embeddings)
    .where("label > 2")
    .limit(5)
    .select(['text', 'keywords','label'])
    .toArray();

console.log('Search Results with filter:');
console.log(filteredResultsesults);

What's Next?

That's pretty much it for the Getting Started section.

To learn more about vector databases, you may want to read about Indexing to get familiar with the concepts.

If you've already worked with other vector databases, dive into the Table Guide to learn how to work with LanceDB in more detail.

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