<strong>Connection pooling</strong> is reusing database connections instead of creating new ones for each request. It dramatically improves performance by avoiding the overhead of establishing connections.
The Taxi Stand Analogy
Instead of calling a new taxi each time (slow), you go to a taxi stand where taxis wait. Use one, return it to the stand. Connection pools work the same way.
Taxis (Connections)
Ready to use
Taxi Stand (Pool)
Waiting area
Passengers (Requests)
Need rides
Needs DB Connection
Reusable Connections
Execute Query
Create pool at startup
Initialize 10 connections to database
Request needs connection
User query arrives
Borrow from pool
Get available connection (instant)
Execute query
Run SELECT * FROM users
Return to pool
Connection goes back for reuse
Wrong
"More connections = better performance"
Correct
<strong>Too many connections hurt performance</strong>. Each connection uses memory. Optimal pool size depends on your workload, typically 10-50 connections.
API server performance:
Without pooling: Create connection (50ms) + query (5ms) = 55ms per request
With pooling: Borrow connection (0.1ms) + query (5ms) = 5.1ms per request
Result: 10x faster! Can handle 10x more requests
Pool of 20 connections handles 1000s of requests/second