Sunset photo
Photo from sunset at Jane's parents' house.
Data Guard with Transparent Application Failover (TAF)
One of the problems with Data Guard is that even after switching/failing over to the standby database, all clients need to be reconfigured to communicate with the new primary. The simplest way to achieve this (if using a centralised tnsnames.ora ), is to modify the file and add the line " (FAILOVER=YES) ", and either multiple ( DESCRIPTION=...) or (ADDRESS=...) lines, one for each of the standby systems, in the order that the client should attempt connections . This tells the client to try each address in turn until one succeeds. Doing so provides basic failover functionality within Oracle Net, and will probably function correctly most of the time. Though be aware - because both primary and standby can share the same instance name (e.g. the same SID, therefore the same connection string), there is potential for this simple scheme to go wrong. An example in an active data guard environment (where the standby is open read only): a temporary network issue causes all c
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