.tip

Mar 16, 2026 · one of the small things

ssh -L reaches a database that is only on the private network

The database only accepts connections from the bastion. Tunnel through it, and your local client thinks the database is on localhost.

ssh -N -L 5433:db.internal:5432 bastion
psql "host=localhost port=5433 dbname=app"

-N runs no remote command, only the tunnel. Put it in ~/.ssh/config as a LocalForward line and opening it is one word.

shelloperations

~/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