Configuration parameters that affect data replication

Synchronized data replication can increase the amount of time it take longer to free the log buffer after a log flush. The DRINTERVAL, DRTIMEOUT, and HDR_TXN_SCOPE configuration parameters can adjust synchronization and system performance.

The DRINTERVAL configuration parameter indicates whether the data-replication buffer is flushed synchronously or asynchronously to the secondary database server. If this parameter is set to flush asynchronously, it specifies the interval between flushes. Each flush impacts the CPU and sends data across the network to the secondary database server.

If the DRINTERVAL configuration parameter is set to 0, the synchronization mode that is specified by the HDR_TXN_SCOPE configuration parameter is used. The HDR_TXN_SCOPE configuration parameter specifies whether HDR replication is fully synchronous, nearly synchronous, or asynchronous.

In fully synchronous mode, transactions require acknowledgement of completion on the HDR secondary server before they can complete.
In asynchronous mode, transactions do not require acknowledgement of being received or completed on the HDR secondary server before they can complete.
In nearly synchronous mode, transactions require acknowledgement of being received on the HDR secondary server before they can complete.

The DRTIMEOUT configuration parameter specifies the interval for which either database server waits for a transfer acknowledgment from the other. If the primary database server does not receive the expected acknowledgment, it adds the transaction information to the file named in the DRLOSTFOUND configuration parameter. If the secondary database server receives no acknowledgment, it changes the data-replication mode as the DRAUTO configuration parameter specifies.