FROM 17MS TO 0.04MS: HOW TO DESIGN THE RIGHT SQL INDEX

Summary from the TLDR Data newsletter

Good SQL indexes come from real query patterns, not the table schema. Composite indexes need the right column order, usually equality filters first and sort or range columns after, with EXPLAIN ANALYZE used to verify the result. The right indexes cut example queries from 17ms to 0.04ms and 436ms to 0.5ms.