What is Azure Cosmos DB?

Azure Cosmos DB is a **fully managed NoSQL database** service by Microsoft. It is designed for **global distribution, high availability, and low-latency performance**.

Key Features of Cosmos DB

• Multi-Model Support: Supports document, key-value, column-family, and graph databases.
• Global Distribution: Data is replicated automatically across multiple regions.
• Guaranteed Latency: Less than **10ms** read and write latency.
• Five Consistency Levels: Strong, Bounded Staleness, Session, Consistent Prefix, and Eventual.
• Automatic Scaling: Adjusts throughput dynamically.

Creating an Azure Cosmos DB Account

Step 1: Create a Cosmos DB Account

az cosmosdb create --name my-cosmosdb --resource-group MyResourceGroup --kind MongoDB

Step 2: Create a Database

az cosmosdb database create --name mydatabase --resource-group MyResourceGroup --account-name my-cosmosdb

Step 3: Create a Collection

az cosmosdb collection create --name mycollection --resource-group MyResourceGroup --account-name my-cosmosdb --database-name mydatabase

Connecting to Cosmos DB

Using Python (MongoDB API)

from pymongo import MongoClient

cosmos_url = "mongodb://my-cosmosdb.documents.azure.com:10255/?ssl=true"
client = MongoClient(cosmos_url, username="myuser", password="mypassword")

db = client["mydatabase"]
collection = db["mycollection"]

# Insert a document
collection.insert_one({"name": "Azure Cosmos DB", "type": "NoSQL"})

# Fetch documents
for doc in collection.find():
    print(doc)

Using Node.js

const { CosmosClient } = require("@azure/cosmos");

const endpoint = "https://my-cosmosdb.documents.azure.com";
const key = "your-primary-key";

const client = new CosmosClient({ endpoint, key });
const database = client.database("mydatabase");
const container = database.container("mycollection");

// Insert a document
async function addItem() {
    await container.items.create({ id: "1", name: "Azure Cosmos DB", type: "NoSQL" });
}

addItem();

Scaling Azure Cosmos DB

Manual Scaling

az cosmosdb update --name my-cosmosdb --resource-group MyResourceGroup --throughput 10000

Auto Scaling

az cosmosdb update --name my-cosmosdb --resource-group MyResourceGroup --max-throughput 50000

Global Replication

Azure Cosmos DB supports **multi-region replication**.

az cosmosdb update --name my-cosmosdb --resource-group MyResourceGroup --locations eastus westus

Monitoring and Performance

Check Throughput Usage

az monitor metrics list --resource MyResourceGroup --name my-cosmosdb --metric "TotalRequestUnits"

Conclusion

Azure Cosmos DB is an **enterprise-grade NoSQL database** with **global distribution, low-latency, and scalability**.

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