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Function documentation Synchronizing Master and Standby Components Locate the document in its SAP Library structure

Use

The database system synchronizes the standby components in a hot standby system constantly with the master component. The log entries that the master component writes in the log area are automatically imported in the standby component, and the corresponding transactions are executed.

The dataset of a standby component always corresponds - with a delay - to the dataset of the master component. You can configure this time delay using the HS_DELAY_TIME special database parameter.

Note

Unlike standby components, with a standby database log backups are imported from backup media.

Activities

The database system starts the synchronization at certain intervals. The master component informs the standby component regularly (see special database parameter HS_SYNC_INTERVAL) about the point to which new log entries were written. The standby components then report to which point they have read the log, import the log entries up to a certain point in time (see special database parameter HS_DELAY_TIME) and then execute the corresponding transactions.

Master and standby components use the same database parameters. If a new standby component is set up, it receives an exact copy of the parameters of the master component. Changes to the parameter are always made on the master component and are then transferred automatically to all standby components.

 

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