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Being both a mediocre biz dev guy and a nerd means I get to post on the Developer blog as well as our Company blog, and today I’d like to…
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Being both a mediocre biz dev guy and a nerd means I get to post on the Developer blog as well as our Company blog, and today I’d like to…
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COUNT STOPKEY operation (the where ROWNUM <= N predicate) doesn't process over ~4 Billion rows and returns wrong results
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tanelpoder.com
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15 years ago
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eng
I was running tests on some very large tables on an Exadata cluster and found an interesting bug. Instead of having to query 4Billion row tables, I have reproduced this case with a cartesian join… Check this. I’m generating 8 Billion rows using a 3-way cartesian join of set of 2000 rows. So, this results in 2000 * 2000 * 2000 rows, which is 8 billion rows. SQL> with sq as (select null from dual connect by level <= 2000) select count..
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COUNT STOPKEY operation (the where ROWNUM <= N predicate) doesn't process over ~4 Billion rows and returns wrong results
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tanelpoder.com
-
15 years ago
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eng
I was running tests on some very large tables on an Exadata cluster and found an interesting bug. Instead of having to query 4Billion row tables, I have reproduced this case with a cartesian join… Check this. I’m generating 8 Billion rows using a 3-way cartesian join of set of 2000 rows. So, this results in 2000 * 2000 * 2000 rows, which is 8 billion rows. SQL> with sq as (select null from dual connect by level <= 2000) select count..
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I had a studio here and helped put on some shows and exhibits. White Lightning Wherehouse from Nelle Owens Dunlap on Vimeo.
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I love VMware workstation. I keep VMs around for basically every version of every major Linux distribution, and use them heavily for all kinds of kernel testing and development. This post is a quick writeup of my networking setup with VMware Workstation, using dnsmasq to assign my VMs addresses and provide a DNS server to resolve VM addresses. The objective I want to be able to resolve my VM’s hostnames so that I can ssh to them, or run oth..
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I love VMware workstation. I keep VMs around for basically every version of every major Linux distribution, and use them heavily for all kinds of kernel testing and development. This post is a quick writeup of my networking setup with VMware Workstation, using dnsmasq to assign my VMs addresses and provide a DNS server to resolve VM addresses. The objective I want to be able to resolve my VM’s hostnames so that I can ssh to them, or run oth..
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As an architect for a team with a large number of people, I have a couple of problems: I often make decisions that turns out to be quite crappy. Even when I think I’ve written or drawn something that’s smart, it often turns out that it’s incomprehensible to everyone else Luckily, I’ve noticed that most developers have characteristics that almost always counter these weaknesses: Most developers are pretty smart, especially when they’re tryin..
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Yesterday I wrote about rearranging my schedule to get up earlier to get home earlier and get a chance to walk Keeda in the morning and as well as at night. I set my alarm to 6am, woke up, and collapsed back into bed. It did not work. Tonight I’m trying a different method - I’m pretending it’s Daylight Savings and setting my iPhone clock forward an hour. That way when I get up at 7am I’m really getting up at 6! Genius.
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Grid Style Sheets Must Die I have been aware of Grid Style Sheets for quite a while, but I long ago dismissed them as a fad like CSS Resets. Recently though it came to my attention that OSCommerce 2.3 switched to the 960 Grid Style to replace its table based layout system. I spend most of my development time working with OSCommerce and thought it would be good to understand this change so I could decide whether or not to integrate it i....
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Grid Style Sheets Must Die I have been aware of Grid Style Sheets for quite a while, but I long ago dismissed them as a fad like CSS Resets. Recently though it came to my attention that OSCommerce 2.3 switched to the 960 Grid Style to replace its table based layout system. I spend most of my development time working with OSCommerce and thought it would be good to understand this change so I could decide whether or not to integrate it i....
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I recently started working on a personal project - a web application - and faced a difficult decision. What technology stack do I use? I like my personal projects to both fulfil a requirement and to teach me something in the process. Java is my native language, so I initially thought I’d build it in wicket-spring-hibernate. The problem is that I can only work on the project for a few hours a week, and I find that developing in Java just..
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So I’ve been playing this game on Facebook and thought I might post a screenshot of it in action. Then I thought, I could 1-up that and play a video! So here it is:
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So since making the linux to Mac transition, I have this mindset of things on the Mac are supposed to "just work" and be fantastic and marvelous and flawless. This preconception was shattered again when I tried to burn some CDs recently. I downloaded and ISO and tried to burn it with Finder. In Ubuntu, if you try to burn a single .iso file to disc, it prompts you that you probably want to just make a disc from that CD image, and thus does t..
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Ellen mentioned doing NaNoWriMo this year and inspired me to participate as well! I had the intention of participating in the National Novel Writing Month a couple of years ago but never seemed to have the strength to keep going with my novel and it fizzled out. This year I’m committed - and hope I stay that way despite how ridiculously busy I’ve been. I already have the idea for my novel in my head and have started planning chapter by c..
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I have realized that my normal 9-5 schedule seems very inefficient. As it stands right now, here’s my general daily schedule:
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I saw Sufjan Stevens last night at the Uptown Theater in Kansas City. It was an awesome, awesome show. I think it was more enjoyable because I had only a vague idea of what to expect, as I hadn’t listened to his Age of Adz album beforehand. I’m not a big fan of electronica or synth anything, and his new work is a mishmash of 80’s-style beats (“Put on your slow-jam pants,” he told the crowd before one song) and, well, I don’t know what. ..
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I saw Sufjan Stevens last night at the Uptown Theater in Kansas City. It was an awesome, awesome show. I think it was more enjoyable because I had only a vague idea of what to expect, as I hadn’t listened to his Age of Adz album beforehand. I’m not a big fan of electronica or synth anything, and his new work is a mishmash of 80’s-style beats (“Put on your slow-jam pants,” he told the crowd before one song) and, well, I don’t know what. ..
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Read currently running SQL statement’s bind variable values using V$SQL_MONITOR.BIND_XML in Oracle 11.2
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tanelpoder.com
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15 years ago
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eng
The title pretty much says it. In Oracle 11.2, if you have the Diag+Tuning Pack licenses and the SQL monitoring kicks in for your SQL statement, then instead of the old fashioned ERRORSTACK dump reading you can just query the V$SQL_MONITOR.BIND_XML to find the values and metadata of your SQL statement’s bind variables. I’ve written an example here: https://tech.e2sn.com/oracle-living-books/oracle-troubleshooting/oracles-real-tim....
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Read currently running SQL statement’s bind variable values using V$SQL_MONITOR.BIND_XML in Oracle 11.2
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tanelpoder.com
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15 years ago
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eng
The title pretty much says it. In Oracle 11.2, if you have the Diag+Tuning Pack licenses and the SQL monitoring kicks in for your SQL statement, then instead of the old fashioned ERRORSTACK dump reading you can just query the V$SQL_MONITOR.BIND_XML to find the values and metadata of your SQL statement’s bind variables. I’ve written an example here: https://tech.e2sn.com/oracle-living-books/oracle-troubleshooting/oracles-real-tim....
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What happened to the kvass...and the Mad Hatter's Tea Party challenge
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liza.io
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15 years ago
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eng
I thought I’d post a quick update on my kvass making initiative. There’s not really much of an update. The five fermentation days are up and my kvass smells like beer and tastes like it, too. I don’t know if it tastes like good beer as I don’t like beer, so to me it’s pretty darn horrible. What a waste! I guess I’ll just have to buy some fake plastic-bottled kvass from Amazon.com
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What if you had to report daily your progress on the tasks you’re programming in your project. Wait, you say: “I already do that in my daily standup meetings”. But if your standup meeting is anything like most standup meetings out there, you’ve got a serious blind spot. What if I said that writing code doesn’t constitute progress. Code is effort, not value. In order to demonstrate value, you have to be able to show your progress to someone ..
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As much as I like things to be perfect I soon discovered from my startup camp experience that its far more important to have a minimum viable product out there and generating interest. After all how can you determine how worthwhile your time investment is without throwing out your ideas and testing the reaction. That’s always something scary for any developer, but probably is the correct approach. And so I am releasing a quick weekend p..
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Ctrl-1 is the magic “do what I think” button in Eclipse. Whenever I press it, Eclipse seems to come up with something that’s helpful in the current context. In this blog post, I illustrate 10 things that Eclipse hide under the ctrl-1 keypress. This is a follow up on my post on Eclipse stenography. I got some comments on my last post about Eclipse stenography about the animated gifs. I know this can be annoying, but I considered the alternat..
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So in my first computer science course, one of the earliest labs with Stephen Wong was called Ball World. Professor Wong had set up some fill-in-the-blanks java code for us that brought up a basic frame. We wrote code to add some ball sprites and we had to define their velocity and have code to detect collisions and compute new velocities after balls collided with each other or the boundaries. I still remember the first time you get every....
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I managed to get the following error the other day while helping migrate and upgrade some MySQL databases for a client. mysqldump: Got error: 1356: View 'database.table' references invalid table(s) or column(s) or function(s) or definer/invoker of view lack rights to use them when using LOCK TABLES The above appeared anytime I tried to dump the database to a SQL file using mysqldump. Its actually one of the better errors I have seen come ..
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When working on replacement projects, I often find I need to make minor changes to an existing database that is still in use by one of several other applications. Initially, it may seem like situation will force you to conform to the current database schema. But there are other options, even though they may not be for those who are faint of heart. The general pattern when you want to evolve a database that is in use by legacy system, is to ..
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So the other weekend I attended a Sydney Startup Camp . While I am not going to say that the entire experience was positive im not going to call out the reasons in too much depth. What I have noticed is that its very ‘clicky’. It seems that despite the organizers attempt to break up up people who know each other it seems to be impossible. A lot of the experience seems to focus on the non technical side of things which is good for people ..
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A common problem in software engineering is avoiding confusion and errors when dealing with multiple types of data that share the same representation. Classic examples include differentiating between measurements stored in different units, distinguishing between a string of HTML and a string of plain text (one of these needs to be encoded before it can safely be included in a web page!), or keeping track of pointers to physical memory or vi..
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A common problem in software engineering is avoiding confusion and errors when dealing with multiple types of data that share the same representation. Classic examples include differentiating between measurements stored in different units, distinguishing between a string of HTML and a string of plain text (one of these needs to be encoded before it can safely be included in a web page!), or keeping track of pointers to physical memory or vi..
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Thankfully not a zombie virus (I checked - she did not develop a taste for human flesh). Yesterday we saw that my dog Keeda had a paw infection and eye infection (yes, at the same time). The eye infection isn’t unusual, she tends to get this once a year or so and my mom has found that rinsing the eye lightly with chamomile tea helps to get rid of it within a couple of days (apparently they use this same method for babies in Ukraine).
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So my trusty Linksys wireless router up and died on me a few months ago. Of course, in a geek's world, lack of Wifi at home is a stop-the-line emergency, so of course I just immediately drove to a local brick and mortar store to get a replacement. I bought a Belkin as it was the cheapest. It seems to not have the ability to remember MAC to IP mappings for any significant length of time, which meant all my laptops and VMs were constantly cha....
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Robot cars, that is. Google has had its robotic cars travel over 140k miles. For safety, of course, they have an actual driver in the car in case the car doesn’t react correctly.
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When I was little and living in Ukraine I remember having Kvass, a traditional drink from that area. I realized that there doesn’t seem to be anywhere to buy kvass in Perth, so being the amazing chef that I am I decided to make some of my own.
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When I was a kid, my parents would send me to church camp almost every day. At the camp, we did typical campy-type stuff like singing around campfires or listen to stories. Of course, being a church camp, these songs and stories were often biblical and faith-based.
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Team SoundCloud hacking at Music Hack Day Barcelona Last weekend a team of SoundCloud attended Music Hack Day Barcelona. This blog post is…
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A growing number of college students are approaching the end of their college careers and are worried about finding a job. One reason is academic inflation.
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Team SoundCloud hacking at Music Hack Day Barcelona Last weekend a team of SoundCloud attended Music Hack Day Barcelona. This blog post is…
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The most fundamental difference between hash and nested loop joins
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tanelpoder.com
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15 years ago
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eng
Basically the most fundamental (or biggest or most important) difference between nested loop and hash joins is that: Hash joins can not look up rows from the inner (probed) row source based on values retrieved from the outer (driving) row source, nested loops can. In other words, when joining table A and B (A is driving table, B is the probed table), then a nested loop join can take 1st row from A and perform a lookup to B using that ..
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The most fundamental difference between hash and nested loop joins
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tanelpoder.com
-
15 years ago
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eng
Basically the most fundamental (or biggest or most important) difference between nested loop and hash joins is that: Hash joins can not look up rows from the inner (probed) row source based on values retrieved from the outer (driving) row source, nested loops can. In other words, when joining table A and B (A is driving table, B is the probed table), then a nested loop join can take 1st row from A and perform a lookup to B using that ..
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Sometimes I’m asked to write or speak about something with very little preparation. In these situations, I need a tool that can help me: Organize my thoughts quickly Prioritize the wheat before the chaff Maintain a coherent train of thought I find a very useful structure for archiving this to be what I call “three-by-three”: Three main points with three subpoints each. Forcing myself to keep to a structure will make my thoughts flow more qu..
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A while back, I was poking around LLVM bugs, and discovered, to my surprise, that LLVM doesn’t support the va_arg intrinsic, used by functions to accept multiple arguments, at all on amd64. It turns out that clang and llvm-gcc, the compilers that backend to LLVM, have their own implementations in the frontend, so this isn’t as big a deal as it might sound, but it was still a surprise to me.
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