NO, SQL.

Why PostgreSQL is Probably the Answer

A Series of Arguments Prepared for the Consideration of Software Engineers

The Claim

NoSQL databases allow developers to add new fields and change data structures on the fly without requiring schema migrations or downtime. This flexibility is particularly valuable during rapid development cycles or when dealing with external data sources that may change structure unexpectedly.

The Reality

PostgreSQL's JSONB type provides all the schema flexibility of a document store while maintaining ACID compliance and the power of SQL querying. Moreover, it allows you to gradually formalize your schema as your data model stabilizes, giving you the best of both worlds.

Show Me The Code
NoSQL Approach
// MongoDB approach
db.users.insert({
  name: "John",
  email: "john@example.com",
  preferences: {
    theme: "dark",
    notifications: true
  }
})

// Add new field without migration
db.users.update(
  { email: "john@example.com" },
  { $set: { newField: "value" } }
)
✓
PostgreSQL Solution
-- PostgreSQL JSONB approach
CREATE TABLE users (
  id SERIAL PRIMARY KEY,
  data JSONB
);

INSERT INTO users (data) VALUES ('{
  "name": "John",
  "email": "john@example.com",
  "preferences": {
    "theme": "dark",
    "notifications": true
  }
}');

-- Add new field just as easily
UPDATE users
SET data = data || '{"newField": "value"}'::jsonb
WHERE data->>'email' = 'john@example.com';

The Claim

NoSQL databases are built from the ground up for horizontal scalability, making it easier to handle large-scale applications by adding more machines to the cluster.

The Reality

PostgreSQL offers multiple robust solutions for horizontal scaling, including built-in table partitioning, logical replication, and extensions like Citus that enable true distributed SQL capabilities.

Show Me The Code
NoSQL Approach
// MongoDB sharding setup
sh.enableSharding("mydb")
sh.shardCollection("mydb.users",
  {user_id: "hashed"})

// Add more shards as needed
sh.addShard("mongodb0.example.net:27017")
sh.addShard("mongodb1.example.net:27017")
✓
PostgreSQL Solution
-- PostgreSQL native partitioning
CREATE TABLE users (
  user_id bigint NOT NULL,
  created_at timestamp NOT NULL,
  data jsonb
) PARTITION BY HASH (user_id);

-- Create partitions
CREATE TABLE users_0 PARTITION OF users
  FOR VALUES WITH (modulus 4, remainder 0);
CREATE TABLE users_1 PARTITION OF users
  FOR VALUES WITH (modulus 4, remainder 1);

-- Using Citus for distributed SQL
CREATE EXTENSION citus;
SELECT create_distributed_table('users', 'user_id');

The Claim

NoSQL document stores are better suited for handling deeply nested, hierarchical data structures that mirror the object structures used in application code.

The Reality

PostgreSQL's combination of JSONB for flexible structures and recursive CTEs for hierarchical querying provides more powerful tools for handling complex data structures than document stores, while maintaining data integrity.

Show Me The Code
NoSQL Approach
// MongoDB nested document
db.departments.insert({
  name: "Engineering",
  manager: {
    name: "Jane",
    title: "Director"
  },
  teams: [{
    name: "Frontend",
    lead: "Bob",
    members: ["Alice", "Charlie"]
  }]
})
✓
PostgreSQL Solution
-- PostgreSQL hierarchical data
CREATE TABLE departments (
  id SERIAL PRIMARY KEY,
  name TEXT NOT NULL,
  structure JSONB,
  parent_id INTEGER REFERENCES departments(id)
);

-- Query with recursive CTE
WITH RECURSIVE dept_tree AS (
  SELECT id, name, structure, 1 as level
  FROM departments WHERE parent_id IS NULL
  UNION ALL
  SELECT d.id, d.name, d.structure, dt.level + 1
  FROM departments d
  JOIN dept_tree dt ON d.parent_id = dt.id
)
SELECT * FROM dept_tree ORDER BY level;

The Claim

NoSQL databases provide better performance for specific access patterns and very large datasets by sacrificing consistency guarantees.

The Reality

PostgreSQL's sophisticated query planner, extensive indexing options, and materialized views often provide better performance than NoSQL solutions while maintaining ACID compliance.

Show Me The Code
NoSQL Approach
// MongoDB indexes
db.users.createIndex(
  { "lastLogin": 1, "status": 1 }
)

// Simple range query
db.users.find({
  lastLogin: {
    $gte: new Date('2024-01-01'),
    $lt: new Date('2024-02-01')
  }
})
✓
PostgreSQL Solution
-- PostgreSQL specialized indexing
-- BRIN index for time-series data
CREATE INDEX idx_logins_brin
ON user_logins USING BRIN (login_timestamp);

-- Partial index for active users only
CREATE INDEX idx_active_users
ON users (last_login)
WHERE status = 'active';

-- Materialized view for analytics
CREATE MATERIALIZED VIEW user_stats AS
SELECT date_trunc('day', created_at) as day,
       count(*) as new_users
FROM users GROUP BY 1;

The Claim

NoSQL databases provide a more natural development experience by allowing developers to store data in the same format as their application objects.

The Reality

Modern PostgreSQL features like JSONB, composite types, and array types provide the same developer convenience while maintaining data integrity.

Show Me The Code
NoSQL Approach
// MongoDB document
db.products.insert({
  name: "Widget",
  price: 99.99,
  tags: ["electronics", "gadget"],
  specs: {
    weight: "250g",
    dimensions: "10x5x2cm"
  }
})
✓
PostgreSQL Solution
-- PostgreSQL modern types
CREATE TYPE product_specs AS (
  weight text,
  dimensions text
);

CREATE TABLE products (
  id SERIAL PRIMARY KEY,
  name text NOT NULL,
  price decimal(10,2),
  tags text[],
  specs product_specs
);

-- Rich querying capabilities
SELECT * FROM products
WHERE tags @> ARRAY['electronics']
  AND (specs).weight = '250g';

The Claim

NoSQL databases handle globally distributed deployments better, with built-in support for eventual consistency and multi-master replication.

The Reality

PostgreSQL's logical replication, combined with extensions like BDR, provides sophisticated multi-region deployment options with tunable consistency levels.

Show Me The Code
NoSQL Approach
// MongoDB replica set config
rs.add("node1.us-east.example.com")
rs.add("node2.eu-west.example.com")

// Read from nearest node
db.users.find().readPref("nearest")
✓
PostgreSQL Solution
-- PostgreSQL logical replication
CREATE PUBLICATION app_publication
FOR TABLE users, orders;

CREATE SUBSCRIPTION app_subscription
CONNECTION 'host=primary-db.example.com'
PUBLICATION app_publication;

-- Conflict resolution with BDR
CREATE OR REPLACE FUNCTION resolve_conflict()
RETURNS trigger AS $$
BEGIN
  IF NEW.updated_at > OLD.updated_at THEN
    RETURN NEW;
  END IF;
  RETURN OLD;
END;
$$ LANGUAGE plpgsql;

The Claim

NoSQL databases are necessary for high-performance applications. Traditional SQL databases cannot handle the load of modern web-scale applications.

The Reality

PostgreSQL powers some of the world's largest applications. Instagram handles 1+ billion users, Uber processes 10+ million writes per second, and Reddit, Twitch, and Apple iCloud all rely on PostgreSQL.

Show Me The Code
NoSQL Approach
// MongoDB scaling claims
- "Web-scale" by default
- Eventually consistent
- Horizontal scaling
- No ACID overhead
- Schema-free performance
✓
PostgreSQL Solution
-- PostgreSQL real-world stats
- Instagram: 1B+ users
- Uber: 10M+ writes/second
- Reddit: Main database
- Twitch: Core infrastructure
- Apple iCloud: User data

-- Performance features
- Parallel query execution
- Just-In-Time compilation
- Advanced query planning

The Claim

NoSQL databases offer better enterprise support and commercial backing for mission-critical deployments.

The Reality

PostgreSQL has a robust enterprise support ecosystem including EDB, AWS RDS, Google CloudSQL, Azure, Crunchy Data, and 2ndQuadrant offering 24/7 support.

Show Me The Code
NoSQL Approach
// MongoDB Enterprise
- Atlas cloud platform
- Single vendor support
- Commercial licensing
- Proprietary tools
- Vendor lock-in risks
✓
PostgreSQL Solution
-- PostgreSQL Enterprise
- Multiple vendors available
- Open-source foundation
- No vendor lock-in
- 24/7 support options
- Active security patches
- Cloud-native solutions