How To Determine Secondary Database State With RDBSyncForward?
We are using redundant Oracle databases using RDBSyncForward, setup as per the ETM White Paper "Oracle Historian Replication EN".
My question is: how can I tell if the connection to the secondary Oracle database is healthy?
I see we have the internal DPEs _RDBArchive.dbConnection.connected to let us know that WInCC OA has a connection to Oracle, and _RDBArchive.dbConnection.usedHost to let us know which database is currently active. However, say we have connected = TRUE and usedHost = HOST_A, which DPE(s) can tell me whether HOST_B is healthy or not?
There is no indication in WinCC OA dpes, because the connection to the daatabase is not establisched. What you can do is to preiodically check if the link working. This can be done with an SQL statement from the primary server to the secondary server. There is always a DB link between the two Oracle server.
the SQL would look like following:
select * from dual@<YOURDBLINK>;
you can run this SQL with direct SQL commands periodically out of WinCC OA then (using our built in control functions).