Comparing FastAPI with Golang Standard Library

Overview

• FastAPI: A fast Python web framework.
• Golang: Using its standard library.
• Tests conducted on AWS with Kubernetes.

Test Setup

Baseline Test

• Aim: Test framework performance using hardcoded objects returned in JSON.
• Metrics: Latency, throughput, CPU usage, memory usage, error rate, CPU throttling.

Second Test

• POST request handling: Parses body, generates UUID & timestamp, inserts record into PostgreSQL.
• Cache: Memcached used for caching.
• Metrics: Includes Prometheus metrics for database, cache operations, CPU usage, connection pool size.
• Infrastructure: Memcached on m7a.xlarge, PostgreSQL on specialized 2xlarge, EKS cluster with two node groups.

Infrastructure Details

• Node Groups: General-purpose instances for apps, compute-optimized for Prometheus, Grafana, etc.
• Cost Efficiency: Compute-optimized instances are cheaper due to less memory, used for non-memory-intensive operations.

Baseline Test Results

FastAPI

• Latency: Higher than Go application.
• Throughput: Reached 13,000 requests per second.
• CPU Usage: High, leading to throttling and performance degradation.
• Availability: Dropped to zero when overloaded.
• Memory Usage: Notable spike before failure.

Golang

• Latency: Lower than FastAPI.
• Throughput: Reached around 62,000 requests per second.
• Consistency: Maintained performance across tests.
• Notes: Limit Go user threads to avoid Kubernetes throttling.

Second Test Results

FastAPI

• Workers: Increased from 2 to 4 to improve CPU usage.
• Performance: Reached 800 requests per second.
• Limit Reached: Within 10-15 minutes.

Golang

• Performance: Better than FastAPI; lower database and cache latency.
• Throughput: Started failing at 35,000 requests per second due to file descriptor limits.

Additional Observations

• PostgreSQL & Memcached CPU Usage: Tracked during tests.
• Connection Pool: Limited to 500, increased database connections over 1,000.
• Go Limit: Could be higher with proper file descriptor settings.

Conclusion

• FastAPI performance is underwhelming compared to Golang.
• Source code for tests and configurations available in the video description.
• Encouragement to improve FastAPI and contribute back.

Additional Benchmarks

• Mention of other benchmarks such as Rust vs. Go on the same channel.