Hello Sandro,
There is no SAP note explaining the TAF preconnect on SAP.
You can only find the best practices guide and see the sample provided by SAP. The FAILOVER_MODE is set to BASIC.
You can set either of them according to your demands.
–BASIC failover
The application connects to a backup node only after the primary connection fails. This approach has low overhead, but the end user experiences a delay while the new connection is created.
–PRECONNECT failover
The application simultaneously connects to both a primary and a backup node. This offers faster failover, because a pre-spawned connection is ready to use. But the extra connection adds everyday overhead by duplicating connections.
Best regards,
Jiajia