||SQL Server Tips by Robin Schumacher
What is Ratio Analysis?
Ratio-based analysis has been around for many years. It used to be
the only technique database administrators employed when called upon
to diagnose the cause of database slowdown. Using one or more
cherished SQL scripts; the DBA would conduct an examination of key
ratios such as database memory use, contention, I/O, network
utilization, and others to pinpoint the area(s) responsible for
Once a particular area was identified as suspect, the standard
remedy was to increase the resources for that area. This often did
the trick but occasionally failed to produce any real performance
Should ratio-based analysis still be used to assist in determining
the overall health of a database, and if so, how should it be done?
When performed correctly, ratio-based analysis definitely has a
place in the DBA’s performance-tuning arsenal. Performance ratios
are very good roll-up mechanisms for busy DBAs, making at-a-glance
Many DBAs have large database farms to contend with and cannot spend
time checking detailed wait-based analysis outputs for every SQL
Server they oversee. Succinct performance ratios can assist in such
situations by giving DBAs a few solid indicators that can be scanned
quickly to see if any database server requires immediate attention.
The above book excerpt is from:
High-Performance SQL Server DBA
Tuning & Optimization Secrets