SQL in your browser

1 Million Row Challenge.

Build a real Postgres database in this tab, run a slow query against a million rows, then pick the index that fixes it. Every number you see is measured on your device, live.

Step 1 · Build the database

1,000,000 orders, in your browser

Real Postgres, running on your device. One table, orders, with a power user (#4242) who has placed about a thousand of them.

Step 2 · Run the slow query

User #4242 opens their orders page

SELECT * FROM orders
WHERE user_id = 4242
ORDER BY created_at DESC
LIMIT 20;

Step 3 · Add an index

Which index makes it fast?

Pick one. It runs for real on your 1,000,000 rows. Each index is tested on its own: the previous one is dropped first.