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SQL Server and Daylight Savings Time

Joe Pollock has to turn the clocks forward:

At the start of Daylight Saving Time (DST), which is this weekend in the UK, the clocks will move forward by one hour at 1am. Apart from the fact that we all lose an hour of our night’s sleep, what effect will this have on your scheduled jobs in SQL Server?

As we saw in my last blog post, we know that the SQL Server engine always carries on regardless of when the clocks change, it knows that this has happened, but nothing unusual occurs in the engine itself. However, SQL Server Agent, which runs scheduled tasks, is not the same, as this directly impacts how it works. 

Read on to see what can happen. Also, this can be relevant when you have unique key constraints on datetime values.