Impact of LEAP Second on SQL Server Databases


SQL Server is not really impacted by the leap second. Most affected systems by the second leap are those based on Linux and Java, and those that depends heavily on replicated data. Windows based systems do not seem affected by the second leap as they use Windows Time Service through external NTP Time Server. It is recommended that Systems admins sync domains controllers rather than waiting till next synchronization, which might take up to one week. SQL Server database engine is also not affected by the second leap, as it is reading time through the OS.

Most applications also will not be affected by the second leap, as they don’t depend on seconds in calculations. Some of the systems might get affected, especially those that might be real-time systems or those that depend on seconds on their internal calculations. Money Markets systems, and similar ones, such as securities, FX, derivatives and electronic trading systems that channel orders in real-time might get impacted by the second leap. However, this is depending on systems architectures and the way orders are channeled through local markets, international markets, Bloomberg or Reuters.

In most cases, timestamps and execution orders are handled by intermediate systems or market systems, and therefore we do not really need to worry about it.
In case specific critical application or system needs to be reviewed, it is suggested to do a thorough study to application architecture, timing dependencies, and code review if necessary.

Hope this was helpful.

This is applicable for below versions of SQL Server

SQL Server 2014

SQLServerF1 Team
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