Tuesday, March 27, 2012

Daylight Savings Time changes coming in 2007

I apologize ahead of time if this has been covered. I tried searching but found only the OS specific response to my question (http://www.microsoft.com/windows/timezone/dst2007.mspx).

With the coming changes to DST in 2007, is there -- or is there even a need to -- patch either SQL Server 2005 or 2000 to account for those changes?

Doug,

have you received any responses yet to this question? I too have the same question and have only found the page that you already linked too as well. Please let me know if you find out anything.

Thanks,

Chad (chad.smith@.lucasfilm.com)

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There has been a lot discussion in the SQL org about this. To date, we have determined SQL is pulling all dates from the OS so no updates from SQL are needed. If we eventually find a problem we'll definitely release an update.

Thanks,

Peter Saddow

|||What about releasing a "rebasing" utility like the one issued for Outlook and Exchange?|||How about date arithmetic? Wouldn't that be affected by this change?|||

Consider this:

You have a calculation that comes up with a date/time in the future with a result as UTC value. Let's assume that future date falls somewhere between 3/11, 2AM and 4/1 2AM. This UTC value must be wrong because you haven't applied any DST related patches yet. If you store this value for future use, it will be wrong.

You apply OS DST patch.

You do the same calculation as before. This time, UTC will not be different by just the amount of time that passed between two calculations. Extra hour will be added because that is what the patch corrects.

The first value is still wrong and something must be done about it. That's why Microsoft issued "rebasing" tool for Outlook and Exchange.

It's not enough to say: "you'll be fine as soon as you patch OS". This doesn't fix bad dates that are being calculated and stored today.

I'm still waiting for someone to explain to me why the above line of thinking doesn't apply to SQL Server (or any other Windows application).

All you MVPs out there?

|||The anwser to your question, is that SQL server itself is not responsible for the data being stored in it. So any application that is storing its data in SQL server will need to come out with an update to compensate for the change in Daylight Savings Time if the developer deems there to be an issue, where the dates and times that are stored in it would be affected.|||

By now SQL Server has been added to the list of Microsoft products affected by DST change. It will requre patching. That was the original issue that started this thread.

I don't know how SQL Server scheduler stores dates but some schedulers have been affected if they store dates as UTC (or GMT). For me, jury is still out on this.

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Here is some SQL script that I’ve come up with to calculate the daylight savings for -2006 and +2007.

http://2pttechnology.com/Web/forums/thread/19.aspx

|||I am a computer illiterazzi. I just want a simple, no hassle patch to fix my computer which is a Windows XP 2002 Service Pack. There are so many selections, I am terrified I will pick the wrong one and screw my expensive new computer. I don't use outlook to my knowledge. I can't find that the daylight savings patch has been downloaded automatically. There are a gadzillion downloads in my computer record. Please help. Thanks.

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