How did I learn about Transaction Log, Redo Log, and Undo Log as a developer?

#sql #database #performance #learning

👉 The hard way.

It wasn’t from a course or documentation — it was from bringing down production.

Not because of a DELETE without WHERE, but from a massive delete that quietly filled up the transaction logs and exhausted every bit of allocated space.
Production froze. Everyone looked at the DB.
And the culprit? Me. 😅

I’ve done it twice — once on Sybase (T-log) and once on Oracle (Redo Log).
Different companies, same mistake.

So here’s my message to all the data analysts and data wranglers:
If you’re using the production database to temporarily store and later delete large analysis datasets — be aware that those deletes are fully logged.

Every delete = undo + redo + log space consumed.
If the log fills up, the whole system can grind to a halt.

✅ Use NOLOGGING / minimal logging where possible
✅ Do batched deletes with commits
✅ Or better yet — don’t use prod as your scratchpad

Your DBA (and your uptime) will thank you. 🙏