Voice of the DBA

Category: Blog

  • Getting Control of Your Instances with Policy Based Management

    Managing lots of database or instances in an efficient manner requires a DBA to find automated ways to ensure their databases are configured correctly. In SQL Server 2008, Policy Based Management (PBM) was introduced to help DBAs implement a framework across their systems.

    This presentation discusses the philosophy of managing systems in groups and with declared rules, policies, and procedures. PBM is discussed from an architectural standpoint, as well as with practical demonstrations of policy creation, import, export, and limitations. There are also demonstrations on how to execute policies outside of the PBM interface using Powershell.

    Level: 100

    Length: 60 minutes

    Slides: PPTX, code

  • Question what you think

    Good advice from Jeff Bezos.

  • Windows 8 First Impressions

    I haven’t worked with Window 8 at all. I’m not a big beta tester, and it’s been a busy few months for me, so I haven’t bothered to mess with any of the previews. My Win 7 desktop works well for me, and I haven’t bothered to think about doing anything different.

    Today I was at Best Buy, needing to get a new UPS for my computer since I had a power outage and a failure of the battery in my existing system. I grabbed two, but as I was walking by, I saw laptops with Windows 8 on them. It isn’t supposed to release until Friday, and perhaps these were just setup since there weren’t prices, but I stopped to look at them.

    The first one was a Lenovo Yoga. It’s interesting, and I was reading about it recently in that it has a cover that folds completely over. It can become a tablet, but the keyboard is exposed.

    yoga13_web_detail_000

    The other was a Toshiba Satellite S4310. Nothing fancy here, but definitely a more reasonable cost. I checked later and found it at $900 for a nice setup.

    toshiba4310

    In both machines the start menu was up, and it’s obvious you pick one of the tiles to get to the app. However getting back to the start menu wasn’t obvious. I hit the Windows key, which brought it up, but I couldn’t figure out a swipe method to get it back. I’m sure there’s a shortcut, but in 4-5 minutes of trying stuff, I couldn’t figure it out.

    I did get to swipe over from the left and change applications. That was interesting, and it worked fine. It was smooth and while I only ran 3 things, this hardware performed fine. The placement of the title bar and the view was different, but the applications are the applications. They work fine.

    I will say the response to touching the screen was fast and quick, almost too quick. In trying to scroll, two fingered, OSX style, I found it trying to zoom in or out as I moved. More me than the system, and I’m sure it’s something I’d get used to quickly.

    I like the idea of having this start screen with some information on it, but that’s more for a tablet. I can’t imagine seeing this much in my work, and wouldn’t even want to bring it up as a screen saver.

    Using a few apps, browsing, typing, it just works. I’m not sure how much of the “Windows 8” experience, I’d even bother with in daily life if I didn’t have a tablet. As it is on the iPad, I mostly live in apps. The OS isn’t really important.

    Not sure if I’ll upgrade or get anything for me, but my wife needs a new laptop, and a few of these look nice. Not sure if she’d like the tablet interface, and the Yoga seems weird, but I’ll ask her and see.

  • Trace Flag 2371 and Statistics

    One of the issues that I see published often on forums like SQLServerCentral is the advice to update statistics on your tables if you have strange performance issues, or sudden changes in performance. Statistics are important for the query optimizer, and you should understand the basics of how they work.

    However there’s a problem with statistics. They get out of date. SQL Server will automatically update statistics, but it doesn’t do this constantly. It does it after 20% of the table changes (by default). If you have 1000 rows, that means 200 rows changed (or added) can trigger the update. If your table has 50 changes every couple days, you’ll get statistics updated every week.

    If you have 1mm rows (think large, historical data here), then those same 50 changes won’t trigger statistics updates for a long time. 200,000 changes will be needed then.

    There’s a trace flag, 2371, that can help with the minimum needed to trigger a stats update (or you can do this with your own jobs). By choosing this, you can lower the minimum for triggering an update.

    What you do really depends on your issues. If you find poor performance in queries, look for wildly incorrect estimates of rows in your query plans. If you find that your statistics aren’t being updated, or not updated enough, you might enable the trace flag, or create your own job to update statistics manually.

    Note that if you are rebuilding indexes, you don’t need to also update statistics on the columns in the index. They are done as part of the index rebuild.