John Watson's blog
Submitted by John Watson on Sun, 2014-05-11 06:16
Can this parameter really boost performance? This simple test suggests that it can.
Submitted by John Watson on Sat, 2014-05-10 06:28
Unified Audit is a major architectural change: fast, easy, and impossible for the DBA to bypass. On upgrade to Oracle 12c, you really should enable it. The earlier method that we all use is pretty awful.
Submitted by John Watson on Mon, 2014-04-07 09:02
The concept of an adaptive plan is that execution of a statement can start with one plan, and (during execution) switch to another. A pretty amazing capability. No need to run the statement to completion and try again: correct it in flight.
Submitted by John Watson on Sat, 2014-02-22 09:26
I was at the Connecticut Oracle User Group re-launch meeting last week, talking about some of the 12c new features that I specially like: those related to what I call "the self-learning database".
Submitted by John Watson on Sat, 2014-02-01 09:13
Why does the CBO get it wrong? Often because it has insufficient information. No matter how often you analyze your tables, if your queries use multi-column predicates, the CBO will mis-calculate the cardinalities. You have to understand your data, and create extended statistics to correlate the columns. How many people do this? Hardly any. Not a problem any more: release 12c can do this for you. If you configure it appropriately.
Submitted by John Watson on Sun, 2014-01-26 10:34
A necessary part of a cluster is the cluster interconnect: the private network between the cluster nodes. This component is critical for both reliability and scalability, and configuring it for fault tolerance and capacity is a matter of burning importance for the DBA and his System Administrator (not to mention the end users). One question is, should this be managed by the operating system or by Oracle?
Submitted by John Watson on Wed, 2013-12-04 03:41
I have seen articles that misrepresent a Flex Cluster, even this book Expert Oracle RAC 12c which is written by people who know better (Oracle ACE directors, an OCM, an Oak Table member) gets it wrong, because of a reliance on beta documentation.
Submitted by John Watson on Mon, 2013-11-18 03:03
In earlier releases, running a shell script from the Scheduler was awkward. Oracle has realized this, and introduced a new job type in 12c that makes it simple.
Submitted by John Watson on Sat, 2013-10-05 11:40
One often sees requests for test cases, typically when a user has a SQL performance issue. So many users appear to have problems with producing a suitable test case that Uncle Oracle provides routine to automate this. There are no longer any excuses for not providing a test case. Here is an intro to how to do it (code tested on 11.2.0.3 and 12.1.0.1).
Submitted by John Watson on Sun, 2013-09-08 03:52
The inverted table format can deliver fast and flexible query capabilities, but is not widely used. ADABAS is probably the most successful implementation, but how often do you see that nowadays? Following is a description of how to implement inverted structures within a relational database. All code run on Oracle Database 12c, release 12.1.0.1.
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