# @dataengineeringtamil on Instagram

- **Type:** Image
- **Original URL:** https://www.instagram.com/p/DU8i_ZxkmsW
- **Gondola URL:** https://gondola.cc/posts/63365834-dataengineeringtamil-instagram
- **Thumbnail:** https://img.gondola.cc/tr:w-,h-,fo-auto/postThumbnails/fe05b18296.jpg
- **Posted:** 2026-02-19T16:22:46.000+00:00
- **Account Owner:** Data Engineering Tamil (@dataengineeringtamil) — https://gondola.cc/dataengineeringtamil

## Caption

My query took 2 minutes. I added ONE line. Now it's 0.3 seconds. 🚀

Me: "Why is this so slow?" 
Senior Dev: "Do you have an index?" 
Me: "A what now?"

The Problem:

SELECT * FROM orders 
WHERE customer_id = 12345;
-- ⏱️ 127 seconds

The Fix:

CREATE INDEX idx_customer 
ON orders(customer_id);
-- ⏱️ 0.3 seconds

The Rule: Index columns in your WHERE clause.
That's it. 400x faster.

What obvious thing did you learn embarrassingly late? 👇

#SQL #DataEngineeringtamil #DataEngineering

## Stats

- **Views:** 0
- **Likes:** 230
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- **Comments:** 2

## Tags

dataengineering, sql, dataengineeringtamil

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