MongoDB Best Practices

35 min

MongoDB best practices encompass data modeling, indexing, performance optimization, security, and operations. Following best practices ensures your MongoDB deployments are performant, secure, reliable, and maintainable. Best practices are derived from real-world experience and help avoid common pitfalls. Understanding and applying best practices enables you to build production-ready MongoDB applications.

Data modeling best practices include choosing appropriate embedding vs referencing strategies, avoiding deep nesting (limit to 2-3 levels), monitoring document sizes (stay well below 16MB), and designing for access patterns. Schema design should optimize for how data is read, not just how it's written. Understanding data modeling best practices enables efficient, scalable schemas.

Indexing best practices include creating indexes on frequently queried fields, using compound indexes for multi-field queries, monitoring index usage and removing unused indexes, and balancing index benefits with write performance. Indexes should support your query patterns, and you should regularly review and optimize indexes. Understanding indexing best practices enables optimal query performance.

Performance optimization best practices include using explain() to analyze queries, using projection to limit returned data, using $match early in aggregation pipelines, implementing connection pooling, and monitoring performance metrics. Regular performance analysis helps identify and address bottlenecks. Understanding performance best practices enables maintaining optimal database performance.

Security best practices include enabling authentication and authorization, using strong passwords, enabling TLS/SSL encryption, implementing network security (firewalls, IP whitelisting), following least privilege principle, and keeping MongoDB updated. Security should be implemented from the start, not added later. Understanding security best practices enables protecting your data and applications.

Operational best practices include implementing monitoring and alerting, performing regular backups and testing restore procedures, planning for capacity and scaling, documenting configurations and procedures, and following change management processes. Operations should be proactive rather than reactive. Understanding operational best practices enables reliable, maintainable MongoDB deployments.

Key Concepts

Best practices ensure performant, secure, and maintainable MongoDB deployments.
Data modeling should optimize for access patterns.
Indexing should support query patterns and be regularly reviewed.
Security should be implemented from the start.
Operations should be proactive with monitoring and planning.

Learning Objectives

Master

Applying data modeling best practices
Implementing indexing and performance optimization
Following security best practices
Understanding operational best practices

Develop

Understanding production MongoDB deployment requirements
Designing maintainable MongoDB applications
Avoiding common pitfalls and issues

Tips

Design schemas for read patterns, not just write patterns.
Create indexes on frequently queried fields.
Enable authentication and encryption in production.
Monitor performance and set up alerts for issues.

Common Pitfalls

Not following best practices, causing performance and security issues.
Ignoring document size limits, approaching 16MB limit.
Not monitoring performance, missing optimization opportunities.
Not implementing security, exposing data to risks.

Summary

Best practices ensure production-ready MongoDB deployments.
Data modeling, indexing, and performance optimization are essential.
Security and operations require proactive management.
Following best practices avoids common pitfalls and issues.

Exercise

Apply MongoDB best practices to database design and operations.

// Best Practice 1: Use appropriate data types
db.users.insertOne({
  name: "John Doe",
  age: 30, // Use number, not string
  email: "john@example.com",
  createdAt: new Date(), // Use Date object
  isActive: true, // Use boolean
  tags: ["developer", "admin"] // Use arrays for multiple values
})

// Best Practice 2: Use compound indexes efficiently
db.users.createIndex({ email: 1, createdAt: -1 })
db.users.createIndex({ age: 1, city: 1, isActive: 1 })

// Best Practice 3: Use projection to limit data transfer
db.users.find(
  { age: { $gte: 25 }},
  { name: 1, email: 1, _id: 0 } // Only return needed fields
)

// Best Practice 4: Use bulk operations for better performance
db.users.bulkWrite([
  { insertOne: { document: { name: "Alice", email: "alice@example.com" }}},
  { updateOne: { 
    filter: { name: "Bob" }, 
    update: { $set: { age: 31 }}
  }},
  { deleteOne: { filter: { name: "Carol" }}}
])

// Best Practice 5: Use aggregation for complex queries
db.orders.aggregate([
  { $match: { status: "completed" }},
  { $group: { 
    _id: "$customerId", 
    totalSpent: { $sum: "$amount" },
    orderCount: { $sum: 1 }
  }},
  { $sort: { totalSpent: -1 }},
  { $limit: 10 }
])

// Best Practice 6: Use write concerns appropriately
db.users.insertOne(
  { name: "New User", email: "new@example.com" },
  { writeConcern: { w: "majority", j: true }}
)

// Best Practice 7: Use transactions for multi-document operations
const session = db.getMongo().startSession()
session.startTransaction()

try {
  db.accounts.updateOne(
    { _id: ObjectId("account1") },
    { $inc: { balance: -100 }},
    { session }
  )
  
  db.accounts.updateOne(
    { _id: ObjectId("account2") },
    { $inc: { balance: 100 }},
    { session }
  )
  
  session.commitTransaction()
} catch (error) {
  session.abortTransaction()
  throw error
} finally {
  session.endSession()
}

// Best Practice 8: Monitor and optimize performance
// Regular maintenance tasks
db.users.reIndex() // Rebuild indexes
db.runCommand({ compact: "users" }) // Compact collection

// Check slow queries
db.getProfilingStatus()
db.setProfilingLevel(1, 100) // Log queries slower than 100ms

// Best Practice 9: Use proper error handling
try {
  const result = db.users.insertOne({
    name: "Test User",
    email: "test@example.com"
  })
  print("Inserted:", result.insertedId)
} catch (error) {
  if (error.code === 11000) {
    print("Duplicate key error")
  } else {
    print("Error:", error.message)
  }
}

// Best Practice 10: Use environment-specific configurations
// Development
const devConfig = {
  writeConcern: { w: 1 },
  readPreference: "primary"
}

// Production
const prodConfig = {
  writeConcern: { w: "majority", j: true },
    readPreference: "secondaryPreferred"
}

Exercise Tips

Review and optimize indexes regularly: remove unused indexes, add missing ones.
Monitor document sizes: keep documents well below 16MB limit.
Use appropriate write concerns: balance durability with performance.
Implement comprehensive error handling: handle duplicate keys, validation errors, etc.

MongoDB Best Practices