Voice of the DBA

Category: Editorial

  • Yikes!

    I don’t love traveling, but after reading this, I am not sure I want to fly anymore. Perhaps I should take fewer trips next year, or stick to those events that I can drive to?

    The link is about a plane that supposedly had malware introduced into the airline computer network from a USB drive. The plane subsequently crashed and although it’s debatable whether or not the software was the cause, it’s an issue that needs to be examined.

    We use more and more computer systems in our lives, especially in our transportation. Planes, trains, and automobiles, all are becoming more and more computerizes, which I like, but the linkages between all their computer systems is something that concerns me.

    It seems that every few months we are constantly finding new ways in which computer systems can be hacked, altered, or changed, despite tremendous efforts on the part of software vendors. I’m not sure that we’ll ever completely secure our systems, which means that the more interconnections, and more access points we have, the more likely that someone will be able to introduce some type of malware into the system.

    Which could have extremely serious consequences for our safety.

    I don’t like the idea of a USB port in my car having any linkage to the mechanical controls, and I certainly don’t think that this should exist in airplanes. We ought to have a good separation of systems so that a failure or security breech in one, can’t affect any others.

    Steve Jones

  • Are There That Many GUIDs?

    Do a lot of people actually use GUIDs as Primary Keys? I haven’t used them much, and I would have thought that more people chose identity keys. It seems that most of the demos and examples I see from bloggers and speakers are constantly using identities.

    However an informal survey from Peter Bromberg showed that four times as many people actually had GUIDs as their primary keys. The blog actually says that GUIDs are not a good choice, but I’m not sure I agree with that. You can use sequential GUIDs, and you can avoid making them the clustered key, so I think they can work as well as anything.

    There’s nothing inherently wrong with GUIDs, and they should be unique across all of your rows. There have been some reported cases of duplicates, but for most practical purposes, especially in database work, you ought to be able to count on a GUID as unique. They even have the nice capability of being generated by clients, removing the need for an extra round trip when a client needs to insert multiple rows.

    I typically don’t use them because they’re long, hard to remember and type, and hard to view on the screen. I can’t easily compare rows in multiple tables, and it’s easier for me to work with integers.  I don’t recommend them, but if you are going to use them, be sure you understand the pros and cons, and use them appropriately.

    Steve Jones

  • Downtime

    Someone sent me a note recently asking about how to handle unexpected downtime. In an editorial I mentioned that a 7TB database isn’t that large, and this person told me that they had an issue with a 1TB database and running DBCC resulted in a 4 hours of unexpected downtime. The person asked if small businesses needed to accept downtime for serious maintenance.

    I think that it’s rare you run into DBCC issues that require downtime, but when you do, then that downtime is needed. I’m not sure what else you can do since DBCC repair issues often indicate some fundamental hardware issue. I suppose that you could move to new hardware, but you still need to ensure that your database is intact and working.

    A restore from backup might be quicker in these situations, but that will requires some downtime, and it’s something that you have to live with. We still have systems that will fail and need rebuilding, and probably always will.

    I know some companies can afford redundant hardware and failover to secondary systems when they need to check their primary servers. A second copy of the database may or may not allow you to continue to function if you had corrupt pages on your primary, depending on how the data is moved over.

    Most of us, however, just have to live with downtime. If anyone has other ideas or stories on dealing with unexpected maintenance downtime, I would be interested in hearing them in the discussion below.

    Steve Jones

  • Data Portability

    It seems that there is a never ending list of formats that data professionals need to deal with. As I read through posts and articles talking about Integration Services, I’m struck by how many unique solutions people come up with to move data in and out of Excel. They know how to handle multiple worksheets, headers, practically anything that people put into Excel. If there’s a pattern in there, chances are some SSIS worker has a solution.

    This week I saw that Facebook had announced a data portability initiative, giving users the ability to download all their Facebook data into one file. The file can include images, movies, posts, events, etc. and gives you a way to not only back up your data, but perhaps use it for other applications. I’m sure it’s only a matter of time before we have an SSIS package that can load up your information into a SQL Server database. I suspect someone will do it just for the challenge, and not because they have a practical use for it.

    Facebook seems to have been under attack constantly from groups that are concerned about the privacy policies and features of a company that has so much data about individuals. However this new feature seems to show that the company isn’t looking to lock you and your data into their own system. You can now backup your data and shut down your account if you with to move on to another service.

    Recognizing that data is important to users and allowing some level of portability is a feature that I wish more companies would embrace. I’d love to be able to easily move my medical records, my financial investment history, or even my credit data to my own systems as a backup. Or even as a way to document the current state and perhaps ensure that my data is correct.

    Steve Jones