Physical standby vs logical standby
In a 3-tie application scenario:
- If primary db dies, developers can just re-config java connection pool to point to standby db without DBA to manually open the db. For physical standby, you have to manually open it read only
- If primary db wont come back and you want to do a failvoer, you have to restart it if the physical standby database has been opened in read-only mode since the last time it was started. Since the physical db has been oepned read-only in precedding step, you must have to restart it. That means downtime of the whole site.
- If primary do come back , but you do not trust it anymore. You can do a switchover. That will certainly have to re-start physical standby.