Voice of the DBA

Recently I was watching a presentation on how to scale performance in your SQL Server environment and one of the suggestions was setting up Availability Groups (AGs) and having read-intent connections that would query the secondary and not the primary. It's not a bad idea, and the SQL Native Client (and other drivers) support this and make it easy to implement.

The pattern of using multiple connections in an application, one for reads and one for writes, has been suggested often. However, in practice, I've rarely seen this work. Apparently having a connection variable, named dbConn, for writes and a second one, named dbConnReadOnly, for reads is too complex for most developers or teams.

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One of the challenges many people have is focusing their learning efforts along some path. The best way to move forward is with steady effort that guides you through steps to build knowledge or skill. However, with so much information out there on the Internet, how do you decide where you focus your efforts?

Lots of people choose a random method, but the world is full of those people, many of whom never develop strong skills. That might be fine if you are an hobby guitarist or piano player, but it's not the best way to approach your career.

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I would hope most of you reading this know what SQL Injection (SQi) is and how you can prevent it. Or at least what patterns cause problems. If not, here's a short explanation that is worth reading. If you have more questions, ask in our forums.

SQL Injection has been, and continues to be, a problem in many systems. In fact, I chatted with Mike Walsh recently after he'd published this post on an attack for one of his clients. He has some notes that explain how your database server might be vulnerable, as well as a description of a recent attack example. He also notes that many of you are responsible for protecting data, which is separate from other security mechanisms. You need to be sure you are protecting your data, even in vendor applications.

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At the Small Data conference recently, one of the talks looked at hardware advances. It was interesting to see a data perspective on hardware changes, as many of us only worry about the results of hardware: can I get my data quickly? In or out, most of us are more often worried about performance than specs. However, today I thought it might be fun to look at a few changes and numbers to get an idea of how our hardware has changed, in the march towards dealing with more and more data. Big data anyone?

In thinking about disks, I saw a chart that looked at the changes from HDD (hard disk drives) to SDD (solid state drives) to NVMe (Nonvolatile Memory Express). These show read speeds going through the list from 80MB/S to 200MB/s to 5000+MB/s. That's a dramatic change, and not one only in high-end arrays. There are off-the-shelf drives you can put in a desktop that read this fast. If you think about some of the early IBM drives, which read at 8800b/s. Growth in disk speed, inside the timeline of our careers, has grown by a few orders of magnitude in read speed.

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