SQL & APIs · Talking to data
Indexes & query plans
Why some queries take 2 ms and others 2 minutes: B-tree indexes, reading EXPLAIN plans, and the trade-offs of adding indexes.
Step 1 of 7 · Overview25 min read ·
Key idea
Prereqs: SELECT & JOIN, GROUP BY. Next: HTTP APIs & JSON. CMU 15-445 Lecture 8 (B+Trees), condensed.Next: 1. Without an index: full scan