The following video and set of resources are from the webinar broadcast by Red Gate on 21 June 2012.
SQL and PL/SQL are deceptively simple, user-friendly languages, which is great for productivity, but also makes it relatively easy to write bad, non-scalable code. Certain features, in particular, seem to sound an irresistible siren call into a world of Oracle applications that perform poorly and yield unpredictable results.
In this webinar, Tom Kyte, a Senior Technical Architect at Oracle Corporation, and the man behind asktom.oracle.com, takes a look at a few of the worst offenders:
- Triggers - much trickery is possible via triggers, and much of it causes pain, confusion and unexpected side effects
- Indexes, NULLs and cardinality - misinformation abounds with regard to the effect of NULLs on cardinality estimates, and the impact of NULLs on index use
- Implicit conversions - strings to numbers, strings to dates, raw to string… probably #2 on the list of ‘bugs I see time and time (and time) again’
With Tom’s typically example-driven approach, you’ll see first-hand evidence of the damage caused when fundamental features are misused, misunderstood and implemented badly.
A live Q+A session with Tom follows the presentation.
1 Comment
David Wallace
01/08/2012
Tom,
Nice post, I'd add one new evil to the list "GTT's"
Seems a lot of bad plsql code i've seen in the last 5 years, has developers, who are unwilling or unable to understand plsql table types, revert to using GTT's as holding areas for simplifying application logic, without any regard to the scalability aspects and the fact that a GTT segment is still a segment that can cause logical and physical IO
Regards,
David
P.S. keep up the good work, Site's like this help to overcome the misinformation that comes from a Google world where typing "oracle dba" still gets dba-oracle as the second hit :(
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