FastAPI Performance Optimization: A Guide to Efficiency Improvement from Code to Deployment

To optimize the performance of FastAPI, it is necessary to systematically advance from five aspects: code, asynchronous processing, database, caching, and deployment. At the code level: prioritize using `async def` to handle I/O-intensive tasks (such as asynchronous database queries), use generators or pagination to reduce memory usage, and leverage parameter validation to filter invalid requests. For asynchronous programming, distinguish task types: use asynchronous frameworks for I/O-intensive tasks, and submit CPU-intensive tasks to a thread pool via `ThreadPoolExecutor`. The core of database optimization includes connection pool reuse, index optimization (to avoid full table scans), batch operations (e.g., `bulk_insert`), and lazy loading. Caching strategies are suitable for frequently accessed data: use in-memory caching with `cachetools` for simple scenarios, and Redis distributed caching for multi-instance deployments. At the deployment end, use Gunicorn + Uvicorn for multi-process/threading, Nginx reverse proxy for static resources, and containerization (Docker) with K8s for elastic scaling. Optimization should first identify bottlenecks, advance step-by-step from code to deployment, prioritize high-cost-effectiveness issues (such as indexes and caching), and continuously monitor and iterate.

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MongoDB and Redis: Combination Strategies for Caching and Database

This article introduces methods to optimize system performance by combining MongoDB and Redis. MongoDB, a document - oriented database, is suitable for long - term storage of complex semi - structured data (such as product details) but has slow disk I/O. Redis, an in - memory cache, is fast and ideal for high - frequency hot data (such as popular products) but has limited memory. Each has its own bottlenecks when used alone, but their combination allows division of labor: MongoDB is responsible for long - term storage, while Redis handles high - frequency caching, sharing the pressure on MongoDB. Common strategies include: caching hot data from MongoDB (user requests first check Redis; if not found, query MongoDB and update the cache), session management (storing user tokens in Redis), high - frequency counters/rankings (using Redis sorted sets), and temporary data storage. It is necessary to be aware of cache penetration (requests for empty data query MongoDB), cache breakdown (a sudden increase in pressure when hot keys expire), and cache avalanche (a large number of keys expiring and flooding MongoDB). Solutions include caching empty values, random expiration, and preheating the cache. In summary, the combination achieves the division of labor of "long - term storage + high - frequency caching", improving performance. It is necessary to flexibly apply it to different scenarios and pay attention to cache - related issues.

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