A lot of different opinions have been heard on this thread, here is a story
from my own experience.
Couple of years ago I have worked on a Data Guard system with 1 standby
database that was used by the Data Mart database. The standby database was
opened during the day and closed and synchronized during the night hours.
The Data Mart was runing its own ETL job to get data from the standby
database.
When a primary database was patched with the new application version that
produced a huge OLTP activity so the 8 hours of recovery work on the
standby site was not anymore enough to catch all the gap that was produced
during the day between the primary and the standby.
All levels of recovery parallelism/other optimizations didn't help too much.
The business was complaining that it does not see recent data.
The active data guard was not an immediate option.
Quick solution ?
I put a fully automatic incremental backup procedure: the backup was
created, transfered and applied to the standby site, and the whole process
was taking no more than 2 hours.
Everyone (the business, the management) was happy.
Who says incremental backups are useless ?
Dragutin
