20 August 2010

Read Those Assumptions!

I just received this note from a player:
Which of the choices, when executed, results in the display of the phrase "Delete occurred!" (without the double quotes) just once? ... Again, this should have been none because dbms_output does not run if server output is not set. The question did not state that you run the question from query analyzer where server output has been set. I think we are beginning to have too many ambiguities with this challenge stuff. It will be nice to be more explicit as to the context in which the question is being asked.
Actually, I am feeling rather good these days that we have been avoiding very problematic ambiguities in our quizzes. Certainly the number of outright mistakes has plummeted to zero of late.

Now, as I hope many of you know, every single day before you can take the quiz, we show you these assumptions:


Unless otherwise noted in the text of the quiz question, you should assume the following:
  • The database version is 10.2 (Oracle Database 10g Release 2); the edition is Enterprise Edition; the database character set is an 8-bit character set; and the national character set is AL16UTF16.
  • The PL/SQL compiler optimization level controlled through the plsql_optimize_level initialization parameter is set to 2, and all PL/SQL code is compiled without debug information.
  • The session and the environment in which the quiz code executes has enabled output from DBMS_OUTPUT (with an unlimited buffer size), and can reference only those datatypes, programs and database objects defined in the context of the quiz or are available in a default installation of the Oracle instance.
I can understand why they might become invisible after a while, but I urge you to re-read them now and then, both to refresh your memory and to see if anything new has been added.

Regards, Steven

19 August 2010

PL/SQL Challenge was unavailable for 3 Hours on 19 August

Hardware problems at the datacentre hosting the PL/SQL Challenge site led to three hours of downtime, from approximately 6 PM Perth, Australia time to 9 PM. Well, that's where I (Steven Feuerstein) am right now, so that is my point of reference....

We apologize for any inconvenience. Our policy is to void the quiz if it is unavailable for four or more hours, so the quiz is still on for today.

Regards, Steven

18 August 2010

Official Announcement: Forgiveness and Corrections Policy

I will be implementing this policy in the coming weeks, but I wanted to inform you now, because as of today, I will no longer make any manual adjustments to scores due to mistakes or errors. It is simply not possible for me to spend the time to do this. You will see this same text on the Rules page very soon. So here goes....

Forgiveness and Corrections Policy

It is sometimes difficult for developers to play the quiz every day, especially when they go on holiday. Players worry about a significant setback in their rankings.

In addition, players sometimes make mistakes, press the Submit accidentally, or even encounter a problem with the submission of an answer. Yet due to the volume of players on the PL/SQL Challenge, it is impossible to respond to each request for correction.

In response to these scenarios, the PL/SQL Challenge offers a "forgiveness/corrections" policy as follows:

For up to ten days in a quarter, we will adjust a player's quiz record as follows:

1. A missed day will not count as a zero score; instead you will be given a score equal to the average of all scores for that day.

2. A zero score will be replaced with a score equal to the average of all scores for that day.

3. If you missed or scored 0 points for less than 10 days (let's refer to the balance of those days as "FD" or "forgiveness days"), then we will change your score for the FD lowest ranking days in the quarter to match the score of the ranking on that day that equals your average ranking throughout the quarter. In other words, if your average ranking is 125 then on a day in which you were ranked 250, we will identify the score of the person ranked 125, give you that score, and then re-rank.

In conjunction with this forgiveness/correction policy, we will no longer make any manual corrections to scores due to errors on your part or on the part of the website. The above policy will automatically adjust your score to give you maximum possible "recovery" from your ten "worst" days in the quarter. I realize that this may cause some frustration and hurt feelings, but it is the only viable policy for running the PL/SQL Challenge when there are 1300+ daily players!

The adjustment for missed and zero score days will happen at the end of each day. If at the end of the quarter you have not "used up" all ten forgiveness days, the "lowest ranking days" algorithm will be used for the balance of days.

17 August 2010

Live PL/SQL Challenge event at Insync 2010 in Melbourne, Australia

Quest Software and AUSOUG sponsored a PL/SQL Challenge Live quiz at the Insync 2010 conference on 16 August (which took place just 3 hours after I arrived from a very long odyssey from Chicago).

Forty-two developers played the quiz and I am pleased to announce that Jeff Kemp, currently ranked #5 in this quarter on the daily quiz, took first place with a score of 37 points out of a possible maximum score of 43. He wins a $100 giftcard from Westfield Mall. Here is list of the top 20 scorers in the competition:

01 Player JEFF KEMP = 37
02 Player STUART WATSON = 34
05 Player BRETT MCBRIDE = 32
06 Player MARIA DE MESA = 32
07 Player KHOI NGUYEN = 32
08 Player IAN CORKHILL = 31
09 Player MARC THOMPSON = 31
10 Player ROHAN MILTON = 31
11 Player SWEE KEONG TAN = 31
12 Player RAY FEIGHERY = 31
14 Player TIM DANIELL = 30
16 Player THOMAS WENDE = 29
17 Player PANKAJ DADOO = 29
18 Player ROGER SCHNEIDER = 29
19 Player ANTHONY BRUMBY = 29
20 Player R F = 29

Hopefully they will all register at and play the daily quiz of the PL/SQL Challenge as well. They clearly have lots of promise!

Finally we were lucky enough to have Tom Kyte in attendance at the live quiz. He was kindly pointed out two subtle problems with the quiz, so I cleaned those up for the other quizzes this week. One point will also result in a minor change in our assumptions.

Thanks, Tom!

15 August 2010

Adjustments for very fast answers made on 14 August

For the past several weeks, I have posted entries on this blog regarding plans to make adjustments to scores and rankings for players who answer in an amount of time that is far faster than even I can answer my own questions.

Today, I applied my "very fast answer" algorithm, and as a consequence you will see changes in the rankings of players.

Some players moved up, some moved down.

I will now apply this algorithm on a regular basis (likely every two weeks). It is driven by the amount of time it takes me to take the quiz; I will not be publishing these numbers, but rest assured that these times are going to be much faster than players can generally answer the quizzes - if you read the question and answers carefully (and do not log in multiple times to view the quiz).

So I once again offer all players the following advice:

Take your time, read the question carefully and thoroughly. If you answer too quickly (that is, unbelievably too quickly), it does not necessarily mean that you are cheating, but it does mean that I cannot distinguish your pattern of playing from someone who is cheating.

To protect the credibility of the PL/SQL Challenge and to keep all players excited about taking these quizzes every day, I have no choice but to take action.

Warm regards,
Steven Feuerstein