A learning track made for where you are.
Say where you want to get to and what you already know. You get short written lessons, a lot of hands-on exercises, and a skill tree that only stays green while you still remember it.
A free account, then tell it what you want to learn. Your first track is written for you within a couple of days; the sample is ready now.
- Senior to principal — the gaps your last three incidents found, not a generic syllabus.
- One company's interview loop — what that company asks, at the level you're at.
- Veterinary diploma recognition — the clinical exam, drilled, not watched.
Finding indexes nobody uses
An exercise from the sample track — Postgres indexing, hands on.
indexrelname | idx_scan | size -----------------------+----------+-------- orders_legacy_ref_idx | 0 | 412 MB orders_pkey | 0 | 96 MB orders_customer_id_idx| 8813402 | 88 MB
Which index is the best candidate to drop?
orders_legacy_ref_idx
orders_pkey
Zero scans and 412 MB. orders_pkey shows zero too — but it enforces the primary key on every write.
known
fading — a few cards bring it back
ahead