Changes to the source database
result in additional I/O. Queries against the database snapshot require additional
processing time to determine whether the snapshot or the source database should
be accessed. With a single snapshot, the impact should be negligible; the increase
in resources would probably be measurable, but it??™s unlikely it would be perceivable.
But change from one snapshot to ten, and you have a different story. If you
have a large number of snapshots defined on an OLTP database, you may have a
perceivable performance impact. It is unlikely that using database snapshots will
bring the server to its knees, but a decrease in performance is something to keep
in mind when using them.
??? Be wary of using snapshots as a single approach to dealing with user error: Snapshots
can be effective for mitigating user error, but they have serious limitations.
There is no way to guarantee or specifically determine the amount of data loss
when reverting to a snapshot. Be careful not to place total dependence on snapshots
for dealing with user error. Also, make sure that the business owner of the
system is aware of the consequences of using them.
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