.tip

Feb 16, 2026 · one of the small things

git add -p to commit only the lines that belong together

A file holding both a bug fix and an unrelated rename gives you one bad commit or two lazy ones. Patch mode lets you stage it hunk by hunk.

git add -p
# y stage, n skip, s split the hunk, e edit it by hand

Reviewers get a commit that says one thing, and you get a diff you can revert without losing the other change.

git

~/tips/today — 2026-10-19

~cat tips/today

Never build an index on a live table without CONCURRENTLY

postgresqlmigrations

A plain CREATE INDEX takes a lock that blocks every write to the table for the whole build. On a big table that means minutes of outage that look like a hung app.

CREATE INDEX CONCURRENTLY orders_customer_idx ON orders (customer_id);

It's slower and can't run inside a transaction, so you'll have to tell your migration tool. If it fails halfway, it leaves an invalid index behind, so check pg_index.indisvalid and drop it before you retry.

↵ open y yesterday l ls /tips

esc close