Migration of history data stored in SQL Server

The typical SQL Server tables in the Runtime database contain configuration data and certain types of history data. History data that is stored in the typical SQL Server tables includes:

• Data in the AnalogManualHistory, DiscreteManualHistory, and StringHistory tables.

• Classic event and summary data, which is stored in the EventHistory, SummaryHistory, SummaryData, AnalogSnapshot, DiscreteSnapshot, and StringSnapshot tables.

These tables can contain hundreds of thousands of rows, if not millions of rows. Depending of the amount of data to be migrated, migrating this data can take a few minutes to many hours, and in some cases, days.

Important: You must perform the database migration before the server goes back into production, because the history table content will be truncated. Be sure that you have disk space equivalent to two times the size of the Runtime database on the drive to which the history data will be migrated; otherwise, the migration may fail. Back up the Runtime database with the migrated configuration data before migrating the history data.