Guide how to test and compare performance of two SQL Servers

You have your OLD SQL Server. I will be calling this server puppy: OLD, ServerA, or current.

And you have the NEW SQL Server. Will call it: NEW or ServerB.

NEW SQL Server can be anything:

  1. newly purchased on-premises server.
  2. new server in AWS or Azure or any cloud provider. Even Oracle cloud if you feeling adventurous 🙂
  3. or new server on some server with the newest version of SQL Server.

Say you migrating from one OLD to NEW.

So changes you introducing are:

  1. new hardware
  2. new SQL Edition or version
  3. or any mix of those
  4. new connection string
  5. and something else

If you working on really really import SQL Server, then you want need to compare performance of OLD vs. NEW.

Yup, that would sure be nice!

Why? Because you dont want to find out after migration that you just created bunch of problems. Wont look good, right? Yup!

How do you do this?

Here is the way.

This is where SQL Distributed Replay feature comes in.

One of the least known or written about.

Why? Because, as you will see below, to fully appreciate it, it takes a ton of setup to get a result.

But that result is super useful. It clearly shows – whats faster my OLD or NEW. By how much, by what resources. And even shows what SQL statements became slower or faster!

It is easy? Hell no!

Is it super useful? Yup!

Soon I will be posting more part2 on Distributed Replay topic.

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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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