OT: YesSQL Summit 2016 Picture Diary

YesSQL Summit 2016 sponsored by O'Reilly and Axxana was held by the Northern California Oracle Users Group on January 26–28 at the Oracle conference center in Redwood City, California in conjunction with BIWA Summit 2016 and Spatial Summit 2016. The grand raffle prize sponsored by O'Reilly was a full pass to Strata + Hadoop World on March 28–31 in San Jose, California. Save 20% on Strata + Hadoop World conference passes with discount code UGNOCOUG. (more...)

The Twelve Days of SQLT: Day Four: Nobody Did It

Previous installment: Day Three: Just a Mess Without a Clue

I know a funny little man,
As quiet as a mouse,
Who does the mischief that is done
In everybody’s house!
There’s no one ever sees his face,
And yet we all agree
That every plate we break was cracked
By Mr. Nobody.

—Unknown author

The purpose of a SQLT report is to collect all the information that could possibly shed light on a problem (more...)

The Twelve Days of SQLT: Day Three: Just a Mess Without a Clue

P.O.I.S.E.D. is an acronym for a six-step performance tuning method; it stands for Problem, Observation, Interpretation, Solution, Execution, and Documentation. Every problem-solving exercise has these six stages, whether the exercise takes six minutes or six weeks.(read more)

The Twelve Days of SQLT: Day Two: Miles To Go Before We Sleep

SQLT adoption has been limited even though it is the best tool for investigating SQL performance: It is only available as a download from Oracle Support. It creates tables and PL/SQL procedures in the database. It does not support Statspack, only AWR. (read more)

The Twelve Days of SQLT: Day One: Do What You Do Do Well

In his fifteen years with Oracle Support, Carlos Sierra created and perfected a tool called SQLTXPLAIN (SQL Tuning and Explain Plan; SQLT for short) for SQL performance investigations. SQLT collects all the information that could possibly be required to investigate SQL performance including environment information, execution plan history, statistics history (system statistics, table statistics, index statistics), and object definitions.(read more)

OT: Innovative experiment demonstrates the innate social nature of NoCOUG conference attendees

When NeoWorks founder Sri Rajan broached the idea of a hosted happy hour at Casino M8trix after the fall conference, veteran NoCOUG board members were quite dismissive. “NoCOUG members go to NoCOUG conferences in search of the latest and greatest information on Oracle Database such as sharding in Oracle Database 12c Release 2 and extreme performance in MySQL 5.7 and are not as interested in discussing whether Donald Trump or Carly Fiorina has better (more...)

OT: The Best Job Interview of My Life

Bush Sr. was president. The phone kept ringing off the hook after I faxed my resume to the telephone numbers in the want ads on the back pages of Computerworld. The nice people on the phone asked me “how comfortable would I be programming with C”. I could not lie so I replied that “I would be very comfortable programming with C.” That was the only question they asked me, other than “when could (more...)

The Hitchhiker’s Guide to the EXPLAIN PLAN Part 41: Why has my SQL execution plan changed?—A checklist

If the inputs to the CBO change, the plan can change. For example, changes to bind variables can cause the plan to change when it is hard parsed. Therefore one should never be surprised when plans change.(read more)

Sound an alarm: Sharding in the next release of Oracle Database 12c!

There is very little—if anything—about NoSQL that is incompatible with the relational model, the RDBMS vendors will eventually absorb the innovations of the NoSQL camp. Sharding is the perfect example and Oracle will announce support for it an Oracle OpenWorld 2015.(read more)

The Hitchhiker’s Guide to the EXPLAIN PLAN Part 40: Why is it so hard to get SQL performance right the first time?

In the August 2015 issue of the NoCOUG Journal, we asked Stéphane Faroult why it is so hard to get SQL performance right the first time. His answer implies that SQL itself and the way it is taught are the problems.(read more)

SQL and the Art of Problem Solving

What would you do if you were lost in a labyrinth of underground caves? In the dark. With no food. Mark Twain tells the story of how Tom Sawyer and Becky Thatcher got separated from their picnic group and got lost in a labyrinth of underground caves. What’s that got to do with problem solving? I think that the first rule of problem solving is “If at first you don’t succeed, try, try, again.” (more...)

The Hitchhiker’s Guide to the EXPLAIN PLAN Part 39: Unfriending the optimizer statistics

We can’t help attaching meaning to optimizer statistics. After all, they represent our data, don’t they? So we refresh them as frequently as possible and use the largest sample sizes that we can use. Recently, for the first time in my life, I encountered a group of DBAs who understood that statistics do not have any intrinsic meaning; that they are nothing more than a collection of numbers that influence the generation of query plans. (more...)

OT: Some advice for beginning Oracle Database professionals

And if you don’t know Which to Do Of all the things in front of you, Then what you’ll have when you are through Is just a mess without a clue … —Winnie the Pooh in The Tao of Pooh, by Benjamin Hoff Excerpts from the first chapter of my just-released book Beginning Oracle Database 12 c Administration : Thank you very much for buying this book (or for getting a legal copy). Database administrators (more...)

The Hitchhiker’s Guide to the EXPLAIN PLAN Part 38: Utilizing Shakespearean wisdom in database upgrades

“ Those friends thou hast, and their adoption tried, Grapple them unto thy soul with hoops of steel; But do not dull thy palm with entertainment Of each new-hatch'd, unfledg'd comrade.” —the advice of Polonius, counselor to King Claudius, to his son Laertes who is leaving for France in Act 1, Scene 3 of The Tragedy of Hamlet, Prince of Denmark by William Shakespeare Every new version of Oracle Database comes—this should be no (more...)

OT: How to interview an Oracle DBA candidate (NOT)

Yesterday T.J. wrote on the Oracle-L mailing list : “ For those of you who have conducted job interviews, what sort of questions have you found to be effective in evaluating a candidate’s skill level?” I remember the interview at which I could not answer the question “how do you enable block change tracking in a database?” (The answer is ALTER DATABASE ENABLE BLOCK CHANGE TRACKING.) I no longer want to (more...)

OT: Update on the Fourth International NoCOUG SQL Challenge (Part III)

Update on the Fourth International NoCOUG SQL Challenge in progress at https://nocoug.wordpress.com/2015/05/11/fourth-international-nocoug-sql-challenge . Chris Goerg submitted the following MODEL-clause solution. The use of two measures is the key. with d as ( select unique extract(month from dateofbirth) m , extract(day from dateofbirth) d from dates ) select m, d from ( select * from d model dimension by (m,d) measures (0 cd, 0 cm) rules ( -- mark the unique...(read more)

OT: Update on the Fourth International NoCOUG SQL Challenge (Part II)

Update on the Fourth International NoCOUG SQL Challenge in progress at https://nocoug.wordpress.com/2015/05/11/fourth-international-nocoug-sql-challenge . The NoCOUG challenge does not come with a fixed data set such as the 10 dates in the Cheryl’s Birthday problem. Instead contestants are required to solve the problem for all data sets that fit the story. CREATE TABLE DateOfBirth (DateOfBirth DATE NOT NULL); Perhaps because of familiarity with the Cheryl’s...(read more)

OT: Update on the Fourth International NoCOUG SQL Challenge (Part I)

Update on the Fourth International NoCOUG SQL Challenge in progress at https://nocoug.wordpress.com/2015/05/11/fourth-international-nocoug-sql-challenge.

The previous NoCOUG SQL challenges (First, Second, Third) were about devising clever algorithms and then trying to code them in a language (SQL) that was not designed for implementing algorithms. The fourth challenge is more about translating a functional specification into relational algebra or calculus  so it’s closer to what SQL is all about.

The fourth challenge (more...)

OT: Get your next job through Twitter?

From Gwen Shapira’s interview in the May 2015 issue of the NoCOUG Journal : “I got my current job at Cloudera through Twitter. At the time, I was working with a retailer in Japan, as a consultant through Pythian. I was there to help them migrate to Exadata, but their data warehouse system was tightly integrated with Hadoop, and I got to work on this integration too. I got a lot of exposure to Cloudera’s (more...)

Fourth International NoCOUG SQL Challenge (teaser announcement)

The Fourth International NoCOUG SQL Challenge will be published in the May issue of the NoCOUG Journal which will be available at http://www.nocoug.org/Journal/NoCOUG_Journal_201505.pdf at 9 AM PDT on Monday, May 11 . Here's a sneak preview: How Romeo Won the Heart of Juliet Fourth International NoCOUG SQL Challenge Once upon a time, Romeo, the son of Montague, told his cousin Benvolio that he was in love with Rosaline but she was not returning (more...)