Oracle tuning as a life-or-death endeavor
Oracle Database Tips by Donald BurlesonOctober 29, 2015
Chris Lawson, author of the
bestselling book "The
Art and Science of Oracle Performance Tuning" has an amazing
new article titled "When
Performance Tuning is a Matter of Life and Death".
I've noted that Oracle's
intelligent tuning advisors which identify missing indexes and
materialized view opportunities give many DBA's an
over-simplistic view of the complexities of Oracle tuning.
Lawson points out that many DBA's tend to trivialize Oracle
"Those not truly experienced in tuning tend to
trivialize the process, frequently using trite phrases such as ?add missing
indexes? or ?increase buffer cache.?
While Oracle DBA's commonly
support database than are a life-or-death critical (Hospitals,
laboratory equipment), Chris points out that an aggressive
mindset is critical to difficult tuning challenges:
"Here's a tactic I use when I?m faced with an apparently
unsolvable performance problem.
I imagine that the problem is so critical that people will
actually die if I don't resolve the difficulty. I imagine that the lives of
people are actually in my hands."
Chris also notes some of the
real-world tools that are used when mission critical systems are
not performing acceptably:
"Given my new motivation, all limits were off. I considered
all kinds of crazy ideas'server changes, init.ora changes, disk changes,
Chris leverages on his years of
tuning experiences to relate a real-world example where
out-of-the-box thinking solved a critical performance issue.
In his example, Chris uses a novel techniques to perform
"anticipatory caching" of data locks that were used in a
"Since the bottleneck was mostly due to disk i/o, any
improvement in disk access would directly affect the problem job. Since we
knew the exact Sql, we could pre-run Sql that duplicated the ?real? Sql that
would shortly follow. That is, we would pre-cache many of the blocks that
would shortly be needed.
Caching would take place within the SAN unit, as well as at the Oracle
database cache. The entire performance improvement would take place with
absolutely no change to the batch program!"
You can always tell a real-world
tuning professional from a dilettante, and the Oracle community
is lucky to get this practical advice from an experienced Oracle
For more on life-or-death Oracle
databases, See Dr. Hamm's article:
My related notes