What does LSN mean in SQL Server?

sql sql-server architecture logging cdc
Faiz picture Faiz · Jul 17, 2009 · Viewed 31.8k times · Source

What is the meaning of Log Sequence Number? I know that it is of type binary and 10bytes long and it corresponds to the time the transaction happen in DB. But is this a high precision date-time value that is stored in some efficient binary format or is this a function of date-time and something else (for example the serial number of transactions that happen at the same milli second). I did a lot of searching but couldn't find a good answer to this.

Can any one explain with a formula or function that is used to derive the LSN from date-time or anything.

Answer

Mitch Wheat picture Mitch Wheat · Jul 17, 2009

Every record in the SQL Server transaction log is uniquely identified by a log sequence number (LSN). LSNs are ordered such that if LSN2 is greater than LSN1, the change described by the log record referred to by LSN2 occurred after the change described by the log record LSN.

From here.

You should not be concerned with how these are generated.

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