[Case Study] We tuned SQL Server Performance and now its 679 TIMES faster(not a typo)! How did we do it?

Description:
Problem: Slow stored procedure

Notes:
After making couple of small tweaks to the SQL Server stored procedure we were able to get few improvements:

Run time duration improved by: 10,788%
CPU improved by: 10,903%
Disk improved by: 46,180%
Overall stored procedure improvement: 67,871%

What exactly was changed?

-Split a subquery in four parts using UNION
-Replaced ISNULL function in WHERE clause
That’s it!

Why does disk improvement matter for stored procedure speed?

It’s simple. The less you access the disk; the more disk capacity is left over.

It works just like a highway. Say you have 3 lane highway. And 5 cars use it every 1min.

What if you add 50 cars? The speed is still the same because 55 cars don’t overload that highway.

What if you add another 500 or 5000? Now you are starting a slowdown in traffic.

They all still get home. But not at the same speed anymore.

Same with SQL Servers. That’s why speed tuning most critical resources are essential.

The fewer hits there is to the storage, the more capacity there is available.

And the more future cars we can put on it.

Check out more case studies here!

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Mark Varnas

Hey I'm Mark, one of the guys behind Red9. I make a living performance tuning SQL Servers and making them more stable. I channel my SQL into our SQL Managed Services, SQL Consulting and our internal database products.

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