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I just noticed that Jonathan Lewis has announced that he’s writing a new Oracle (fundamental) internals book , due to be out in November. So, I’m happy to add to Jonathan’s announcement, that I’m the tech reviewer of that book! After all the hard work on the Exadata book , I didn’t want to hear about working on any book again (even if it’s just tech reviewing work), but as this is Jonathan’s book, about exactly these topics I love and..
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In May I received the IOUG Select Journal Editor’s Choice Award for my Systematic Oracle Latch Contention Troubleshooting article where I introduced my LatchProfX tool for advanced drilldown into complex latch contention problems (thanks IOUG and John Kanagaraj !). As the relevant IOUG webpage hasn’t been updated yet, I thought to delay this announcement until the update was done – but I just found an official enough announcement (pr..
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In May I received the IOUG Select Journal Editor’s Choice Award for my Systematic Oracle Latch Contention Troubleshooting article where I introduced my LatchProfX tool for advanced drilldown into complex latch contention problems (thanks IOUG and John Kanagaraj !). As the relevant IOUG webpage hasn’t been updated yet, I thought to delay this announcement until the update was done – but I just found an official enough announcement (pr..
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Google+ - Google’s newest attempt to delve into the world of social networking on a scale that it hasn’t done before. Orkut looked promising but enthusiasm died, Google Wave flopped (even though I quite liked it originally, I never used it after the first day), Google Buzz fizzled out. I hope that Google+ will be the hit in Google’s track record of social networking misses.
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Tutto comincia con una normale riunione tra programmatori, magari dedicata all’analisi di un nuovo intrigante progetto software. I toni inizialmente tranquilli all’improvviso si alzano e quello che doveva essere un incontro di routine si trasforma rapidamente in qualcos’altro. La discussione, ora vivace e concitata, diventa un vero e proprio alterco. Sedie penne e matite vengono spostate freneticamente, le voci si sovrappongono l’un l’altra..
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Knowing what you want to achieve before thinking of how to achieve it – a query optimization example
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tanelpoder.com
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14 years ago
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eng
Today I received a question which was a good example of systematic problem solving approach. It was about getting a long-running query to run faster. It took a long time as the correlated subquery in the query was not unnested, was re-visited many times, causing the whole subquery subtree in the plan to be executed again and again). The main part of the question was this: Is there a way to avoid “NOT IN” conversion to “NOT EXISTS” by o..
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Knowing what you want to achieve before thinking of how to achieve it – a query optimization example
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tanelpoder.com
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14 years ago
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eng
Today I received a question which was a good example of systematic problem solving approach. It was about getting a long-running query to run faster. It took a long time as the correlated subquery in the query was not unnested, was re-visited many times, causing the whole subquery subtree in the plan to be executed again and again). The main part of the question was this: Is there a way to avoid “NOT IN” conversion to “NOT EXISTS” by o..
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A mate of mine was looking at a previous article I wrote about Decoding CAPTCHA’s where I pointed people to the following article (PDF) http://la2600.org/talks/files/20040102/Vector_Space_Search_Engine_Theory.pdf He was having some difficulty understanding it so I thought I would write up a very simple explanation of what’s actually happening in the vector space. The vector space isn’t actually that complicated, but getting your hea..
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caption id=“attachment_40030” align=“alignleft” width=“300” caption=“The Quantum Thief by Hannu Rajaniemi”] [/caption]I finished reading The Quantum Thief (affiliate link) by Hannu Rajaniemi, but this will not be a book review. Mostly because I need to read it again before I can honestly feel confident about reviewing this thing. I feel that even though I grasped most of the concepts of how the world works and the individual technologi..
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App Harbor is a great new cloud hosting service, which I’ve been trying out over the last few weeks. It deploys straight from source code…
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In the wake of this brief description of my component binding system, I was asked to provide more details on its implementation. This article is my best attempt to do so! This is a tale of intrigue, excitement, and wonder, in which I try to implement a component-entity system in C#, and stumble upon a remarkable paradigm that merges components with data binding. Note: If you don't have at least a vague concept of component-entity desi..
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Mockups for paintings Makehuman figures imported into SketchUp I’ve been playing around with the Golden Open acrylics a lot lately and preparing a bunch of small and not-so-small supports for new paintings. After trips to MOMA and the Chicago Art Institute’s Architecture and Design room, I’m fired up to try more content using SketchUp as a planning tool for dreamy, sci-fi spacious otherscapes. While playing around with this I ....
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Mockups for paintings Makehuman figures imported into SketchUp I’ve been playing around with the Golden Open acrylics a lot lately and preparing a bunch of small and not-so-small supports for new paintings. After trips to MOMA and the Chicago Art Institute’s Architecture and Design room, I’m fired up to try more content using SketchUp as a planning tool for dreamy, sci-fi spacious otherscapes. While playing around with this I ....
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Thoughts on using Twitter to shrink the size of large classrooms, foster discussion and make class more enjoyable.
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How to Clean Your Dirty Smartphone (Without Breaking Something)
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justingarrison.com
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14 years ago
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eng
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Problem: Take a chessboard and cut off two opposite corners. Is it possible to completely tile the remaining board with 2-by-1 dominoes? Solution: Notice that every domino covers exactly one white tile and one black tile. Counting up the colors, we have 32 white and 30 black. Hence, any tiling by 2-by-1 dominoes will leave two extra white squares unaccounted for. So no such tiling is possible. Problem: Cut one corner off a chessboard.
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Problem: Take a chessboard and cut off two opposite corners. Is it possible to completely tile the remaining board with 2-by-1 dominoes? Solution: Notice that every domino covers exactly one white tile and one black tile. Counting up the colors, we have 32 white and 30 black. Hence, any tiling by 2-by-1 dominoes will leave two extra white squares unaccounted for. So no such tiling is possible. Problem: Cut one corner off a chessboard.
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Problem: Take a chessboard and cut off two opposite corners. Is it possible to completely tile the remaining board with 2-by-1 dominoes? Solution: Notice that every domino covers exactly one white tile and one black tile. Counting up the colors, we have 32 white and 30 black. Hence, any tiling by 2-by-1 dominoes will leave two extra white squares unaccounted for. So no such tiling is possible. Problem: Cut one corner off a chessboard.
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Community Service Mathematics is supposed to be a process of discovery. Definitions, propositions, and methods of proof don’t come from nowhere, although after the fact (when presented in a textbook) they often seem to. As opposed to a textbook, real maths is highly non-linear. It took mathematicians quite a lot of fuss to come up with the quadratic formula, and even simple geometric conjectures were for the longest time the subject of hot ..
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Community Service Mathematics is supposed to be a process of discovery. Definitions, propositions, and methods of proof don’t come from nowhere, although after the fact (when presented in a textbook) they often seem to. As opposed to a textbook, real maths is highly non-linear. It took mathematicians quite a lot of fuss to come up with the quadratic formula, and even simple geometric conjectures were for the longest time the subject of hot ..
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Community Service Mathematics is supposed to be a process of discovery. Definitions, propositions, and methods of proof don’t come from nowhere, although after the fact (when presented in a textbook) they often seem to. As opposed to a textbook, real maths is highly non-linear. It took mathematicians quite a lot of fuss to come up with the quadratic formula, and even simple geometric conjectures were for the longest time the subject of hot ..
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Problem: What is the area of the triangle within the rectangle? Solution: In a moment of inspiration, we draw the following additional line: Now the answer is obvious. Once we split the rectangle into two smaller rectangles, the sides of the triangle become diagonals of their respective rectangles. The diagonals obviously split each of the two smaller rectangles into halves, where one half lies inside our original triangle. Clearly then, th..
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Problem: What is the area of the triangle within the rectangle? Solution: In a moment of inspiration, we draw the following additional line: Now the answer is obvious. Once we split the rectangle into two smaller rectangles, the sides of the triangle become diagonals of their respective rectangles. The diagonals obviously split each of the two smaller rectangles into halves, where one half lies inside our original triangle. Clearly then, th..
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Problem: What is the area of the triangle within the rectangle? Solution: In a moment of inspiration, we draw the following additional line: Now the answer is obvious. Once we split the rectangle into two smaller rectangles, the sides of the triangle become diagonals of their respective rectangles. The diagonals obviously split each of the two smaller rectangles into halves, where one half lies inside our original triangle. Clearly then, th..
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Problem: Find the sum of the first 1000 natural numbers. Solution: Write the numbers twice as follows: $ \begin{matrix} 1 & + & 2 & + & \dots & + & 999 & + & 1000 \\\ 1000 & + & 999 & + & \dots & + & 2 & + & 1 \end{matrix}$ Summing the numbers in each column, we have: $ 2 (1 + 2 + \dots + 1000) = 1001 + 1001 + \dots + 1001$ (1000 times)
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Problem: Find the sum of the first 1000 natural numbers. Solution: Write the numbers twice as follows: $ \begin{matrix} 1 & + & 2 & + & \dots & + & 999 & + & 1000 \\\ 1000 & + & 999 & + & \dots & + & 2 & + & 1 \end{matrix}$ Summing the numbers in each column, we have: $ 2 (1 + 2 + \dots + 1000) = 1001 + 1001 + \dots + 1001$ (1000 times)
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Problem: Find the sum of the first 1000 natural numbers. Solution: Write the numbers twice as follows: $ \begin{matrix} 1 & + & 2 & + & \dots & + & 999 & + & 1000 \\\ 1000 & + & 999 & + & \dots & + & 2 & + & 1 \end{matrix}$ Summing the numbers in each column, we have: $ 2 (1 + 2 + \dots + 1000) = 1001 + 1001 + \dots + 1001$ (1000 times)
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Problem: At any party of 1000 people, must there always exist two people at the party who have the same number of friends at the party? For the sake of this problem, one cannot be friends with oneself, and friendship is bidirectional. Solution: This must always happen. Suppose to the contrary, that every person at the party has a different number of friends at the party. The minimum number of friends one could have is 0, while 999 is the ma..
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Problem: At any party of 1000 people, must there always exist two people at the party who have the same number of friends at the party? For the sake of this problem, one cannot be friends with oneself, and friendship is bidirectional. Solution: This must always happen. Suppose to the contrary, that every person at the party has a different number of friends at the party. The minimum number of friends one could have is 0, while 999 is the ma..
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Problem: At any party of 1000 people, must there always exist two people at the party who have the same number of friends at the party? For the sake of this problem, one cannot be friends with oneself, and friendship is bidirectional. Solution: This must always happen. Suppose to the contrary, that every person at the party has a different number of friends at the party. The minimum number of friends one could have is 0, while 999 is the ma..
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Problem: 1000 players compete in a tournament. In each round, players are matched with opponents, and the winner proceeds to the next round. If there are an odd number of players in a round, one player chosen at random sits out of that round. What is the total number of games are played in the tournament? Solution: 999. Each player loses exactly one game, except for the winner of the tournament.
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Problem: 1000 players compete in a tournament. In each round, players are matched with opponents, and the winner proceeds to the next round. If there are an odd number of players in a round, one player chosen at random sits out of that round. What is the total number of games are played in the tournament? Solution: 999. Each player loses exactly one game, except for the winner of the tournament.
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Problem: 1000 players compete in a tournament. In each round, players are matched with opponents, and the winner proceeds to the next round. If there are an odd number of players in a round, one player chosen at random sits out of that round. What is the total number of games are played in the tournament? Solution: 999. Each player loses exactly one game, except for the winner of the tournament.
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Apologies for the lack of Parkour Ninja updates. I do have fresh info about it somewhere in this post. But first! A list of potentially interesting goings-on of late: School's out for summer! And I'm one year closer to a Computer Science & Engineering undergrad degree from Ohio State. I'll graduate in about a year and a half, right around my 21st birthday actually. I haven't the foggiest idea what to do after that. I'm looking at grad s....
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Last week, I was invited to do a coding dojo for the Java user group in Bergen. I have written a few words about the dojo part of the exercise in a previous blogpost. After “classical” TDD-training, I decided to try something different and gave the group a competition to play with: Extreme startup, a workshop with software created by @rchatley and @mattwynne. The workshop was a huge success and I’m hoping to repeat it soon.
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A Bully By Any Other Name From the New York Times: “Shopping online in late July, Clarabelle Rodriguez typed the name of her favorite eyeglass brand into Google’s search bar. In moments, she found the perfect frames — made by a French company called Lafont — on a Web site that looked snazzy and stood at the top of the search results. Not the tippy-top, where the paid ads are found, but under those, on Google’s version of the gold-medal podi..
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A Bully By Any Other Name From the New York Times: “Shopping online in late July, Clarabelle Rodriguez typed the name of her favorite eyeglass brand into Google’s search bar. In moments, she found the perfect frames — made by a French company called Lafont — on a Web site that looked snazzy and stood at the top of the search results. Not the tippy-top, where the paid ads are found, but under those, on Google’s version of the gold-medal podi..
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A Bully By Any Other Name From the New York Times: “Shopping online in late July, Clarabelle Rodriguez typed the name of her favorite eyeglass brand into Google’s search bar. In moments, she found the perfect frames — made by a French company called Lafont — on a Web site that looked snazzy and stood at the top of the search results. Not the tippy-top, where the paid ads are found, but under those, on Google’s version of the gold-medal podi..
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I write Python and Javascript code. I use Django and jQuery. And I cringe every time I have to run gem install x. I only have a limited understanding of Ruby and hardly any of Ruby on Rails. It seems disorganized to me and hard to process. All this is fine – I don’t have to use any of it if I don’t like it, right? I always knew there was something wrong with the way Ruby works. I don’t mean wrong like murdering children, I just mean wrong....
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I write Python and Javascript code. I use Django and jQuery. And I cringe every time I have to run gem install x. I only have a limited understanding of Ruby and hardly any of Ruby on Rails. It seems disorganized to me and hard to process. All this is fine – I don’t have to use any of it if I don’t like it, right? I always knew there was something wrong with the way Ruby works. I don’t mean wrong like murdering children, I just mean wrong....
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Dangling Nodes and Non-Uniqueness Recall where we left off last time. Given a web $ W$ with no dangling nodes, the link matrix for $ W$ has 1 as an eigenvalue, and if the corresponding eigenspace has dimension 1, then any associated eigenvector gives a ranking of the pages in $ W$ which is consistent with our goals. The first problem is that if there is a dangling node, our link matrix has a column of all zeros, and is no longer column-stoc..
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Dangling Nodes and Non-Uniqueness Recall where we left off last time. Given a web $ W$ with no dangling nodes, the link matrix for $ W$ has 1 as an eigenvalue, and if the corresponding eigenspace has dimension 1, then any associated eigenvector gives a ranking of the pages in $ W$ which is consistent with our goals. The first problem is that if there is a dangling node, our link matrix has a column of all zeros, and is no longer column-stoc..
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Dangling Nodes and Non-Uniqueness Recall where we left off last time. Given a web $ W$ with no dangling nodes, the link matrix for $ W$ has 1 as an eigenvalue, and if the corresponding eigenspace has dimension 1, then any associated eigenvector gives a ranking of the pages in $ W$ which is consistent with our goals. The first problem is that if there is a dangling node, our link matrix has a column of all zeros, and is no longer column-stoc..
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My next book will be Practical Math for Programmers A High-Level Overview of Fully Homomorphic Encryption Searching for Riemann Hypothesis Counterexamples Linear Programming and Healthy Diets Hybrid Images Bezier Curves and Picasso
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