We plan to add a little "reward" for your taking a quiz by offering you a programmer joke or quotation afterwards.
Do you know of any jokes about software, hardware, programming, etc.?
We'd love to use them on the site (as well quotes that you think would be of interest).
To submit a joke or quote, drill down to Quiz Details page for any quiz (through the Library).
Click on the Take Quiz Survey button.
Then click on the Submit Joke/Quote link.
We'll make it easier to submit these soon....
The PL/SQL Challenge (www.plsqlchallenge.com) offers a daily quiz on the PL/SQL language, through which thousands of Oracle technologists demonstrate and deepen their knowledge of PL/SQL. This blog contains posts by the PL/SQL Challenge founder, Steven Feuerstein, as well as comments from players.
11 December 2012
10 December 2012
Where/When Do Players Play?
Throughout November, a poll at the PL/SQL Challenge asked: "We've noticed that, at least for the daily PL/SQL quiz, the bulk of answers are submitted by approximately 16:00 UTC. That makes an awful lot of sense for Europeans, assuming they play the quiz at work. But it is surprising considering all the players in the Americas. We can see when you play your quizzes, but it's far less clear where you take the quiz. Please tell us which of the following choices most closely reflects where and when you usually play your quizzes?"
178 players took the poll, and answered as follows:
Over 600 people answer a quiz through the course of a month, so this response covers roughly a quarter of all active players and likely is an accurate representation of the larger group.
As you can see, the vast majority of players answer quizzes during work hours (which I was glad to see!) and almost a third play during work time - hopefully with the support and blessing of their managers!
178 players took the poll, and answered as follows:
Over 600 people answer a quiz through the course of a month, so this response covers roughly a quarter of all active players and likely is an accurate representation of the larger group.
As you can see, the vast majority of players answer quizzes during work hours (which I was glad to see!) and almost a third play during work time - hopefully with the support and blessing of their managers!
25 November 2012
Upgraded to APEX 4.2 and....Goodbye Website!
Software is a funny thing.
It is, when you think about, a lot like playing god. You get to create your own world and invite people to inhabit it.
But creating (and maintaining) worlds can be really difficult.
For example, this weekend we upgraded to APEX version 4.2.
And after we were done with the upgrade, which occurred without any complications and resulted in successful upgrades for many of the applications running in this APEX instance, we found that the PL/SQL Challenge webpages had become, how shall I put this, blank.
Nothing visible on the page. No HTML to be rendered.
And, strange to say, at this point (22:00 UTC on the 25th of November) we do not yet know what is wrong or how to fix it.
I guess I don't have to tell you troubling it is for me to write the above sentence, but I must.
So as I board a plane to return home from a weekend in New York with my family, I hope that something happens in the next two hours and the website comes to life.
If not, we will just have to do without the PL/SQL Challenge for a little bit. My apologies to all of our devoted players.....
Regards,
Steven Feuerstein
It is, when you think about, a lot like playing god. You get to create your own world and invite people to inhabit it.
But creating (and maintaining) worlds can be really difficult.
For example, this weekend we upgraded to APEX version 4.2.
And after we were done with the upgrade, which occurred without any complications and resulted in successful upgrades for many of the applications running in this APEX instance, we found that the PL/SQL Challenge webpages had become, how shall I put this, blank.
Nothing visible on the page. No HTML to be rendered.
And, strange to say, at this point (22:00 UTC on the 25th of November) we do not yet know what is wrong or how to fix it.
I guess I don't have to tell you troubling it is for me to write the above sentence, but I must.
So as I board a plane to return home from a weekend in New York with my family, I hope that something happens in the next two hours and the website comes to life.
If not, we will just have to do without the PL/SQL Challenge for a little bit. My apologies to all of our devoted players.....
Regards,
Steven Feuerstein
06 November 2012
Change Scoring Algorithm for Playoffs?
A player recently wrote the following to us:
I would like to share some thoughts about Playoff rankings. It is not about my own results, just some thoughts of how to make it more fair. Don't you think it is not too fair, for example, to answer 100% for 35 mins and finally lose to one having 80% correctness and a much shorter time (15 min)?
I know you the same system for the daily quiz as in the playoff, and a player can sometimes win with some errors if they are quick enough. But there is no time limit in the daily quiz, so it's OK there.
Regarding playoff, it is all quite different. Existing situation rewards very quick answers. Even if you make a lot of mistakes, you will probably be among the best. Conversely, if you used almost all the time available, even 100% correctness doesn't guarantee a first place showing.
Why not rank playoff with a very simple algorithm, like that shown below (unweighted_score is the score based only on % correct, independent of time taken to submit the answer):
select player_name, unweighted_score, time
from playoff_results
order by unweighted_score desc, time asc
I see many advantages in this approach. Simplicity, fair, tendency to thoughtful answers. It will stimulate thinking and not guessing...but time still plays an important role. Do you see any limitations?
I would very much like to know what you think, especially players who have participated in a number of playoffs over the past few years. First, though, some background:
The quarterly playoff has changed quite a bit from its original form back in 2010. Originally, the playoff consisted of 10 quizzes to be completed in 10 minutes. The idea was that you should have no or very little time to write code to verify answers and certainly not much time to look up answers or consult with others.
This didn't work out so well. First problem is that it turned out to be very hard for me, Steven, to judge the amount of time needed for a player to read and think through a quiz. So many, many players ran out of time.
The second problem was that coming up with ten new and tough quizzes for the playoff was, well, a challenge.
The third problem had to do with a very hard to track down bug that causes errors when players did run out of time.The site was supposed to very smoothly and elegantly notify you that you had run out of time, and save all answers you'd entered. Ah, software...instead, players would encounter a variety of errors and in some cases, we lost answers.
We were never able to reproduce the error. So we took the following steps instead (to address both of the problems mentioned above):
1. Cut down on number of quizzes from 10 to 5. Ah, what a relief!
2. Extend the amount of time in which players can complete the competition. It is now up to 35 minutes.
3. Remove the countdown clock from the page. We theorized that the Javascript needed for the clock was somehow interfering with other processing on the page and leading to the errors.
And how did this work out for us? Pretty well. We haven't seen those errors since, though that may also be because fewer players are actually running out of time. But this also means that players have a lot more time to research their answers, as opposed to relying solely on their own knowledge and experience to answer the quizzes.
I am not terribly comfortable with the current situation in the playoffs; it's hard not to want to give the 1st place prize to the person with 100% correct answers. Yet I am also reluctant to assign prizes by unweighted score, using submission time only to break ties, at least if we give players 30 minutes to submit their answers.
So...what do you think?
I would like to share some thoughts about Playoff rankings. It is not about my own results, just some thoughts of how to make it more fair. Don't you think it is not too fair, for example, to answer 100% for 35 mins and finally lose to one having 80% correctness and a much shorter time (15 min)?
I know you the same system for the daily quiz as in the playoff, and a player can sometimes win with some errors if they are quick enough. But there is no time limit in the daily quiz, so it's OK there.
Regarding playoff, it is all quite different. Existing situation rewards very quick answers. Even if you make a lot of mistakes, you will probably be among the best. Conversely, if you used almost all the time available, even 100% correctness doesn't guarantee a first place showing.
Why not rank playoff with a very simple algorithm, like that shown below (unweighted_score is the score based only on % correct, independent of time taken to submit the answer):
select player_name, unweighted_score, time
from playoff_results
order by unweighted_score desc, time asc
I see many advantages in this approach. Simplicity, fair, tendency to thoughtful answers. It will stimulate thinking and not guessing...but time still plays an important role. Do you see any limitations?
I would very much like to know what you think, especially players who have participated in a number of playoffs over the past few years. First, though, some background:
The quarterly playoff has changed quite a bit from its original form back in 2010. Originally, the playoff consisted of 10 quizzes to be completed in 10 minutes. The idea was that you should have no or very little time to write code to verify answers and certainly not much time to look up answers or consult with others.
This didn't work out so well. First problem is that it turned out to be very hard for me, Steven, to judge the amount of time needed for a player to read and think through a quiz. So many, many players ran out of time.
The second problem was that coming up with ten new and tough quizzes for the playoff was, well, a challenge.
The third problem had to do with a very hard to track down bug that causes errors when players did run out of time.The site was supposed to very smoothly and elegantly notify you that you had run out of time, and save all answers you'd entered. Ah, software...instead, players would encounter a variety of errors and in some cases, we lost answers.
We were never able to reproduce the error. So we took the following steps instead (to address both of the problems mentioned above):
1. Cut down on number of quizzes from 10 to 5. Ah, what a relief!
2. Extend the amount of time in which players can complete the competition. It is now up to 35 minutes.
3. Remove the countdown clock from the page. We theorized that the Javascript needed for the clock was somehow interfering with other processing on the page and leading to the errors.
And how did this work out for us? Pretty well. We haven't seen those errors since, though that may also be because fewer players are actually running out of time. But this also means that players have a lot more time to research their answers, as opposed to relying solely on their own knowledge and experience to answer the quizzes.
I am not terribly comfortable with the current situation in the playoffs; it's hard not to want to give the 1st place prize to the person with 100% correct answers. Yet I am also reluctant to assign prizes by unweighted score, using submission time only to break ties, at least if we give players 30 minutes to submit their answers.
So...what do you think?
29 October 2012
Results for Q3 2012 Championship Playoff
You will find below the rankings for the Q3 2012 playoff; the number next to the player's name is the number of times that player has participated in a playoff.
Congratulations first and foremost to our top-ranked players:
1st Place: Stelios Vlasopoulos of Belgium wins: Amazon.com US$250 Gift Card .
2nd Place: Frank Schrader of Germany wins: Amazon.com US$175 Gift Card.
3rd Place: Niels Hecker of Germany wins: Amazon.com US$100 Gift Card.
Congratulations to everyone who played in the playoff. I hope you found it entertaining, challenging and educational. And for those who were not able to participate in the playoff, you can take the quizzes next week through the Practice feature.
Steven Feuerstein
Note 1: Looking at the results below, you may wonder how two players can achieve the same % correct and yet the player with the slower time is ranked ahead of a person with a faster time. This can happen due to the fact that the % correct is cumulative across all quizzes in the competition, but you receive a higher score for correct answers on advanced quizzes, compared to intermediate and beginner quizzes.
Note 2: Below the table of results for this playoff, you will find another list showing the playoff history of each of these players.
Congratulations first and foremost to our top-ranked players:
1st Place: Stelios Vlasopoulos of Belgium wins: Amazon.com US$250 Gift Card .
2nd Place: Frank Schrader of Germany wins: Amazon.com US$175 Gift Card.
3rd Place: Niels Hecker of Germany wins: Amazon.com US$100 Gift Card.
Congratulations to everyone who played in the playoff. I hope you found it entertaining, challenging and educational. And for those who were not able to participate in the playoff, you can take the quizzes next week through the Practice feature.
Steven Feuerstein
Note 1: Looking at the results below, you may wonder how two players can achieve the same % correct and yet the player with the slower time is ranked ahead of a person with a faster time. This can happen due to the fact that the % correct is cumulative across all quizzes in the competition, but you receive a higher score for correct answers on advanced quizzes, compared to intermediate and beginner quizzes.
Note 2: Below the table of results for this playoff, you will find another list showing the playoff history of each of these players.
| Rank | Name | Country | Total Time | % Correct | Total Score |
|---|---|---|---|---|---|
| 1 | Stelios Vlasopoulos (5) | Belgium | 13 mins 53 secs | 96% | 3072 |
| 2 | Frank Schrader (9) | Germany | 25 mins 06 secs | 100% | 2998 |
| 3 | Niels Hecker (9) | Germany | 22 mins 14 secs | 87% | 2840 |
| 4 | Tobias Stark (2) | Germany | 28 mins 53 secs | 91% | 2777 |
| 5 | Patrick Barel (1) | Netherlands | 12 mins 35 secs | 78% | 2698 |
| 6 | Mike Pargeter (8) | United Kingdom | 13 mins 40 secs | 83% | 2672 |
| 7 | Viacheslav Stepanov (7) | Russia | 33 mins 05 secs | 96% | 2653 |
| 8 | Marco Siefert (2) | Germany | 30 mins 15 secs | 91% | 2595 |
| 9 | kowido (7) | No Country Set | 28 mins 51 secs | 87% | 2593 |
| 10 | Sean Stuber (6) | United States | 33 mins 06 secs | 91% | 2583 |
| 11 | Giedrius Deveikis (2) | Lithuania | 33 mins 24 secs | 87% | 2537 |
| 12 | Jeroen Rutte (2) | Netherlands | 31 mins 58 secs | 91% | 2526 |
| 13 | Markus Langlotz (2) | Switzerland | 25 mins 00 secs | 83% | 2520 |
| 14 | Justin Cave (7) | United States | 27 mins 11 secs | 83% | 2476 |
| 15 | Jerry Bull (6) | United States | 21 mins 29 secs | 83% | 2475 |
| 16 | Michal Cvan (6) | Slovakia | 31 mins 57 secs | 87% | 2456 |
| 17 | Jens Petersen (2) | Germany | 26 mins 42 secs | 78% | 2451 |
| 18 | Ivan Blanarik (3) | Slovakia | 31 mins 20 secs | 83% | 2428 |
| 19 | Jason H (1) | United States | 31 mins 37 secs | 83% | 2423 |
| 20 | macabre (3) | Russia | 34 mins 00 secs | 87% | 2415 |
| 21 | Gary Myers (5) | Australia | 13 mins 59 secs | 74% | 2400 |
| 22 | Chris Saxon (4) | United Kingdom | 20 mins 38 secs | 74% | 2387 |
| 23 | Frank Schmitt (3) | Germany | 17 mins 55 secs | 83% | 2307 |
| 24 | Zoltan Fulop (3) | Hungary | 33 mins 44 secs | 87% | 2275 |
| 25 | Janis Baiza (5) | Latvia | 15 mins 03 secs | 74% | 2269 |
| 26 | Yuan Tschang (5) | United States | 30 mins 44 secs | 83% | 2210 |
| 27 | swart260 (2) | Netherlands | 17 mins 26 secs | 70% | 2201 |
| 28 | puchtec (1) | Germany | 16 mins 37 secs | 70% | 2198 |
| 29 | Peter Schmidt (3) | Germany | 27 mins 39 secs | 74% | 2127 |
| 30 | Chad Lee (6) | United States | 20 mins 29 secs | 70% | 2100 |
| 31 | Kim Berg Hansen (4) | Denmark | 15 mins 25 secs | 61% | 1967 |
| 32 | Randy Gettman (8) | United States | 23 mins 16 secs | 70% | 1905 |
| 33 | Siim Kask (8) | Estonia | 32 mins 44 secs | 74% | 1890 |
| 34 | Sebastian Kolski (3) | Poland | 18 mins 09 secs | 65% | 1782 |
| 35 | mentzel.iudith (8) | Israel | 34 mins 52 secs | 70% | 1753 |
| 36 | Goran Stefanović (3) | Serbia | 33 mins 44 secs | 74% | 1705 |
| 37 | Vijay Mahawar (1) | India | 34 mins 51 secs | 70% | 1598 |
| 38 | Karel Prech (1) | Czech Republic | 34 mins 55 secs | 65% | 1422 |
| 39 | mark kavalaris (1) | No Country Set | 18 mins 10 secs | 48% | 1132 |
| 40 | koko (1) | Ukraine | 32 mins 12 secs | 52% | 1016 |
Playoff Performance History
After each name, the quarter in which he or she played, and the ranking in that playoff.| Name | History |
|---|---|
| Stelios Vlasopoulos | Q4 2010:38th, Q4 2011:22nd, Q1 2012:30th, Q2 2012:33rd, Q3 2012:1st |
| Frank Schrader | Q3 2010:12th, Q4 2010:30th, Q1 2011:1st, Q2 2011:5th, Q3 2011:1st, Q4 2011:1st, Q1 2012:13th, Q2 2012:3rd, Q3 2012:2nd |
| Niels Hecker | Q2 2010:2nd, Q3 2010:1st, Q4 2010:15th, Q1 2011:7th, Q3 2011:8th, Q4 2011:11th, Q1 2012:2nd, Q2 2012:5th, Q3 2012:3rd |
| Tobias Stark | Q1 2012:35th, Q3 2012:4th |
| Patrick Barel | Q3 2012:5th |
| Mike Pargeter | Q4 2010:22nd, Q1 2011:16th, Q2 2011:10th, Q4 2011:6th, Q1 2012:6th, Q2 2012:20th, Q3 2012:6th |
| Viacheslav Stepanov | Q1 2011:9th, Q2 2011:4th, Q3 2011:14th, Q4 2011:20th, Q1 2012:19th, Q2 2012:12th, Q3 2012:7th |
| Marco Siefert | Q1 2012:31st, Q3 2012:8th |
| kowido | Q1 2011:26th, Q2 2011:9th, Q3 2011:17th, Q4 2011:21st, Q1 2012:4th, Q2 2012:1st, Q3 2012:9th |
| Sean Stuber | Q3 2010:5th, Q1 2011:22nd, Q2 2011:11th, Q1 2012:16th, Q2 2012:9th, Q3 2012:10th |
| Giedrius Deveikis | Q2 2012:7th, Q3 2012:11th |
| Jeroen Rutte | Q3 2010:20th, Q3 2012:12th |
| Markus Langlotz | Q4 2010:11th, Q3 2012:13th |
| Justin Cave | Q3 2010:26th, Q4 2010:3rd, Q1 2011:5th, Q3 2011:3rd, Q1 2012:25th, Q2 2012:2nd, Q3 2012:14th |
| Jerry Bull | Q2 2011:34th, Q3 2011:9th, Q1 2012:14th, Q2 2012:14th, Q3 2012:15th |
| Michal Cvan | Q3 2010:23rd, Q4 2010:25th, Q3 2011:23rd, Q1 2012:12th, Q3 2012:16th |
| Jens Petersen | Q3 2012:17th |
| Ivan Blanarik | Q1 2012:3rd, Q2 2012:15th, Q3 2012:18th |
| Jason H | Q3 2012:19th |
| macabre | Q2 2011:17th, Q3 2011:27th, Q3 2012:20th |
| Gary Myers | Q3 2010:7th, Q4 2010:2nd, Q1 2011:2nd, Q2 2011:1st, Q3 2012:21st |
| Chris Saxon | Q4 2010:16th, Q2 2011:2nd, Q4 2011:8th, Q3 2012:22nd |
| Frank Schmitt | Q4 2011:24th, Q2 2012:4th, Q3 2012:23rd |
| Zoltan Fulop | Q1 2012:17th, Q2 2012:29th, Q3 2012:24th |
| Janis Baiza | Q2 2010:3rd, Q4 2010:7th, Q3 2011:10th, Q4 2011:2nd, Q3 2012:25th |
| Yuan Tschang | Q2 2012:27th, Q3 2012:26th |
| swart260 | Q2 2012:24th, Q3 2012:27th |
| puchtec | Q3 2012:28th |
| Peter Schmidt | Q3 2010:2nd, Q4 2010:14th, Q3 2012:29th |
| Chad Lee | Q2 2011:28th, Q3 2011:19th, Q4 2011:13th, Q1 2012:1st, Q2 2012:26th, Q3 2012:30th |
| Kim Berg Hansen | Q3 2010:34th, Q4 2010:6th, Q1 2011:8th, Q3 2012:31st |
| Randy Gettman | Q3 2010:8th, Q1 2011:27th, Q2 2011:12th, Q3 2011:4th, Q4 2011:12th, Q1 2012:20th, Q2 2012:22nd, Q3 2012:32nd |
| Siim Kask | Q1 2011:30th, Q2 2011:7th, Q3 2011:11th, Q4 2011:4th, Q1 2012:9th, Q2 2012:6th, Q3 2012:33rd |
| Sebastian Kolski | Q1 2012:22nd, Q2 2012:17th, Q3 2012:34th |
| mentzel.iudith | Q4 2010:4th, Q1 2011:18th, Q2 2011:25th, Q3 2011:6th, Q4 2011:5th, Q1 2012:8th, Q2 2012:19th, Q3 2012:35th |
| Goran Stefanović | Q1 2012:34th, Q2 2012:30th, Q3 2012:36th |
| Vijay Mahawar | Q3 2012:37th |
| Karel Prech | Q3 2012:38th |
| mark kavalaris | Q3 2012:39th |
| koko | Q3 2012:40th |
26 October 2012
Amazon-Mandated Maintenance This Weekend
After the downtime we experienced on 25 October, Amazon Web Services informed usethat there are "issues in the Availability Zone" hosting our database and we have been asked to move the instance.
Unfortunately, that instance is really heavy. :-)
No, seriously, my dear friends at Apex Evangelists will be performing the move this weekend. We are not sure of the precise time or how long it will take, so please don't be shocked if you visit this weekend and find the site unavailable.
Unfortunately, that instance is really heavy. :-)
No, seriously, my dear friends at Apex Evangelists will be performing the move this weekend. We are not sure of the precise time or how long it will take, so please don't be shocked if you visit this weekend and find the site unavailable.
Results for 25 October Quiz Not Ranked
With a heavy heart, I have decided to void results for 25 October. They will not be included in rankings, nor used to determine participation in the quarterly playoff.
I did this because several players reported that they were unable to play the quiz, and we know that the site was unavailable for at least four hours - and maybe more, since we are unable to pinpoint the exact time the site became unavailable.
That was a very frustrating experience, waiting and waiting for Amazon Web Services support to take action. Finally they did (thanks to John Scott's prodding) but by then the damage was done.
I did this because several players reported that they were unable to play the quiz, and we know that the site was unavailable for at least four hours - and maybe more, since we are unable to pinpoint the exact time the site became unavailable.
That was a very frustrating experience, waiting and waiting for Amazon Web Services support to take action. Finally they did (thanks to John Scott's prodding) but by then the damage was done.
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