What are the common database optimization methods (how to optimize the database)

The guiding ideology of database optimization is that the written SQL is liked by the optimizer first, and then the bad SQL is eliminated and the bottleneck is found. Because of the existence of a bottleneck, the database throughput can't go up or the query is very slow. From a very large granularity, bottlenecks can be divided into five categories: io memory CPU network lock.

When stuck in a bottleneck, other resources will be idle. Solving the bottleneck or balancing with non-bottleneck resources to maximize the total resources is the correct solution for optimization. For example, indexing is the practice of exchanging space for time.

Because the database is more complex, the optimization ideas will be different with different contexts, so the specific optimization method is the context-free pit.

The mistake most developers make is the so-called "hammer man", that is, they are hammers and look at everything like nails. For example, if they feel slow, they say that they should divide the areas, thinking that one sentence must be written faster than another, regardless of the scene.