Given that those data changes represent fully logged
actions that are sent over the network (including an image of the before data, the
text of the statement making the change, and the after data), this compression can
result in a significant speed improvement.
??? Mirror server write-ahead: The mirror server now moves ahead asynchronously,
writing log information out to its transaction log, regardless of whether it??™s waiting
for further log buffers from the principal.
??? Log cache tuning: Improvements to in-memory log caches maximize the amount
of log data that can be sent from a principal to a mirror at any given time.
What do all of these changes mean? For one, synchronous, two-phase commit operations
will have less of an impact on the user experience, meaning fewer lags between data
entry operations. Also, asynchronous configurations are more likely to stay in a synchronized
state. The bottom line is that these changes are good news for everyone using
database mirroring.
Change Tracking
With the growing emphasis on legal requirements, as noted by the Sarbanes-Oxley Act of
2002 and the Health Insurance Portability and Accountability Act (HIPAA), being able to
have true change history is critical.
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