数据库性能调优向来是 DBA 们最头疼的工作之一。面对动辄上百行的复杂 SQL，到底该建什么索引、建在哪里、建几个，往往需要丰富的经验支撑和反复试错。建少了，查询依然慢；建多了，写入性能受影响，磁盘空间也跟着遭殃。

Follow this step-by-step guide to install PostgreSQL, load data, connect to a database, and execute SQL queries including table joins PostgreSQL is an open-source, object-relational (also called ...