PostgreSQL performance optimization and best practices. Use when writing SQL queries, designing schemas, implementing indexes, or debugging database performance. Covers query optimization, connection management, schema design, and RLS.

PostgreSQL 性能优化与最佳实践。用于编写 SQL 查询、设计表结构、实现索引或调试数据库性能，涵盖查询优化、连接管理、表结构设计和行级安全性。