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• Pay in the future should make you think in the present

  - by BuckWoody

  Distributed Computing - and more importantly “-as-a-Service” models of computing have a different cost model. This is something that sounds obvious on the surface but it’s often forgotten during the design and coding phase of a project. In on-premises computing, we’re used to purchasing a server and all of the hardware infrastructure and software licenses needed not only for one project, but several. This is an up-front or “sunk” cost that we consume by running code the organization needs to perform its function. Using a direct connection over wires you’ve already paid for, we don’t often have to think about bandwidth, hits on the data store or the amount of compute we use - we just know more is better. In a pay-as-you-go model, however, each of these architecture decisions has a potential cost impact. The amount of data you store, the number of times you access it, and the amount you send back all come with a charge. The offset is that you don’t buy anything at all up-front, so that sunk cost is freed up. And financial professionals know that money now is worth more than money later. Saving that up-front cost allows you to invest it in other things. It’s not just that you’re using things that now cost money - it’s that the design itself in distributed computing has a cost impact. That can be a really good thing, such as when you dynamically add capacity for paying customers. If you can tie back the cost of a series of clicks to what a user will pay to do so, you can set a profit margin that is easy to track. Here’s a case in point: Assume you are using a large instance in Windows Azure to compute some data that you retrieve from a SQL Azure database. If you don’t monitor the path of the application, you may not know what you are really using. Since you’re paying by the size of the instance, it’s best to maximize it all the time. Recently I evaluated just this situation, and found that downsizing the instance and adding another one where needed, adding a caching function to the application, moving part of the data into Windows Azure tables not only increased the speed of the application, but reduced the cost and more closely tied the cost to the profit. The key is this: from the very outset - the design - make sure you include metrics to measure for the cost/performance (sometimes these are the same) for your application. Windows Azure opens up awesome new ways of doing things, so make sure you study distributed systems architecture before you try and force in the application design you have on premises into your new application structure.

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• Memory read/write access efficiency

  - by wolfPack88

  I've heard conflicting information from different sources, and I'm not really sure which one to believe. As such, I'll post what I understand and ask for corrections. Let's say I want to use a 2D matrix. There are three ways that I can do this (at least that I know of). 1: int i; char **matrix; matrix = malloc(50 * sizeof(char *)); for(i = 0; i < 50; i++) matrix[i] = malloc(50); 2: int i; int rowSize = 50; int pointerSize = 50 * sizeof(char *); int dataSize = 50 * 50; char **matrix; matrix = malloc(dataSize + pointerSize); char *pData = matrix + pointerSize - rowSize; for(i = 0; i < 50; i++) { pData += rowSize; matrix[i] = pData; } 3: //instead of accessing matrix[i][j] here, we would access matrix[i * 50 + j] char *matrix = malloc(50 * 50); In terms of memory usage, my understanding is that 3 is the most efficient, 2 is next, and 1 is least efficient, for the reasons below: 3: There is only one pointer and one allocation, and therefore, minimal overhead. 2: Once again, there is only one allocation, but there are now 51 pointers. This means there is 50 * sizeof(char *) more overhead. 1: There are 51 allocations and 51 pointers, causing the most overhead of all options. In terms of performance, once again my understanding is that 3 is the most efficient, 2 is next, and 1 is least efficient. Reasons being: 3: Only one memory access is needed. We will have to do a multiplication and an addition as opposed to two additions (as in the case of a pointer to a pointer), but memory access is slow enough that this doesn't matter. 2: We need two memory accesses; once to get a char *, and then to the appropriate char. Only two additions are performed here (once to get to the correct char * pointer from the original memory location, and once to get to the correct char variable from wherever the char * points to), so multiplication (which is slower than addition) is not required. However, on modern CPUs, multiplication is faster than memory access, so this point is moot. 1: Same issues as 2, but now the memory isn't contiguous. This causes cache misses and extra page table lookups, making it the least efficient of the lot. First and foremost: Is this correct? Second: Is there an option 4 that I am missing that would be even more efficient?

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• How to suggest using an ORM instead of stored procedures?

  - by Wayne M

  I work at a company that only uses stored procedures for all data access, which makes it very annoying to keep our local databases in sync as every commit we have to run new procs. I have used some basic ORMs in the past and I find the experience much better and cleaner. I'd like to suggest to the development manager and rest of the team that we look into using an ORM Of some kind for future development (the rest of the team are only familiar with stored procedures and have never used anything else). The current architecture is .NET 3.5 written like .NET 1.1, with "god classes" that use a strange implementation of ActiveRecord and return untyped DataSets which are looped over in code-behind files - the classes work something like this: class Foo { public bool LoadFoo() { bool blnResult = false; if (this.FooID == 0) { throw new Exception("FooID must be set before calling this method."); } DataSet ds = // ... call to Sproc if (ds.Tables[0].Rows.Count > 0) { foo.FooName = ds.Tables[0].Rows[0]["FooName"].ToString(); // other properties set blnResult = true; } return blnResult; } } // Consumer Foo foo = new Foo(); foo.FooID = 1234; foo.LoadFoo(); // do stuff with foo... There is pretty much no application of any design patterns. There are no tests whatsoever (nobody else knows how to write unit tests, and testing is done through manually loading up the website and poking around). Looking through our database we have: 199 tables, 13 views, a whopping 926 stored procedures and 93 functions. About 30 or so tables are used for batch jobs or external things, the remainder are used in our core application. Is it even worth pursuing a different approach in this scenario? I'm talking about moving forward only since we aren't allowed to refactor the existing code since "it works" so we cannot change the existing classes to use an ORM, but I don't know how often we add brand new modules instead of adding to/fixing current modules so I'm not sure if an ORM is the right approach (too much invested in stored procedures and DataSets). If it is the right choice, how should I present the case for using one? Off the top of my head the only benefits I can think of is having cleaner code (although it might not be, since the current architecture isn't built with ORMs in mind so we would basically be jury-rigging ORMs on to future modules but the old ones would still be using the DataSets) and less hassle to have to remember what procedure scripts have been run and which need to be run, etc. but that's it, and I don't know how compelling an argument that would be. Maintainability is another concern but one that nobody except me seems to be concerned about.

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• Wrong statistics in AUX_STATS$ might puzzle the optimizer

  - by Mike Dietrich

  We do recommend the creation of System Statistics for quite a long time. Since Oracle 9i the optimizer works with a CPU and IO cost based model. And in order to give the optimizer some knowledge about the IO subsystem's performance and throughput - once System Statistics are collected - they'll get stored in AUX_STATS$. For this purpose in the old Oracle 9i days some default values had been defined - and you'll still find those defaults in Oracle Database 11g Release 2 in AUX_STATS$. But these old values don't reflect the performance of modern IO systems. So it might be a good best practice post upgrade to create fresh System Statistics if you haven't done this before.  You can collect System Statistics with: exec DBMS_STATS.GATHER_SYSTEM_STATS('start'); and end it later by executing: exec DBMS_STATS.GATHER_SYSTEM_STATS('stop'); You could also run DBMS_STATS.GATHER_SYSTEM_STATS('interval', interval=>N) instead where N is the number of minutes when statistics gathering is stopped automatically. Please make sure you'll do this on a real workload period. It won't make sense to gather these values while the database is in an idle state. You should do this ideally for several hours. It doesn't affect performance in a negative way as the values are anyway collected in V$SYSSTAT and V$SESSTAT. And in case you'd like to delete the stats and revert to the old default values you'd simply execute:exec DBMS_STATS.DELETE_SYSTEM_STATS; The tricky thing in Oracle Database 11.2 - and that's why I'm actually writing this blog post today - is bug9842771. This leads to wrong values in AUX_STATS$ for SREADTIM and MREADTIM by factor 1000 guiding the optimizer sometimes into the totally wrong directon. The workaround is to overwrite these values manually and divide them by 1000. Use the DBMS_STATS.SET_SYSTEM_STATS procedure. See this MOS Note:9842771.8 for the above bug for some further information. This issue is fixed in Oracle Database 11.2.0.3 and above. To get some background information about the statistics collected in please read this section in the Oracle Database 11.2 Performance Tuning Guide. And gathering System Statistics might have some implication if you have mixed workloads - and interacts with DB_FILE_MULTIBLOCK_READ_COUNT. For more information please read section 13.4.1.2.

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• C-states and P-states : confounding factors for benchmarking

  - by Dave

  I was recently looking into a performance issue in the java.util.concurrent (JUC) fork-join pool framework related to particularly long latencies when trying to wake (unpark) threads in the pool. Eventually I tracked the issue down to the power & scaling governor and idle-state policies on x86. Briefly, P-states refer to the set of clock rates (speeds) at which a processor can run. C-states reflect the possible idle states. The deeper the C-state (higher numerical values) the less power the processor will draw, but the longer it takes the processor to respond and exit that sleep state on the next idle to non-idle transition. In some cases the latency can be worse than 100 microseconds. C0 is normal execution state, and P0 is "full speed" with higher Pn values reflecting reduced clock rates. C-states are P-states are orthogonal, although P-states only have meaning at C0. You could also think of the states as occupying a spectrum as follows : P0, P1, P2, Pn, C1, C2, ... Cn, where all the P-states are at C0. Our fork-join framework was calling unpark() to wake a thread from the pool, and that thread was being dispatched onto a processor at deep C-state, so we were observing rather impressive latencies between the time of the unpark and the time the thread actually resumed and was able to accept work. (I originally thought we were seeing situations where the wakee was preempting the waker, but that wasn't the case. I'll save that topic for a future blog entry). It's also worth pointing out that higher P-state values draw less power and there's usually some latency in ramping up the clock (P-states) in response to offered load. The issue of C-states and P-states isn't new and has been described at length elsewhere, but it may be new to Java programmers, adding a new confounding factor to benchmarking methodologies and procedures. To get stable results I'd recommend running at C0 and P0, particularly for server-side applications. As appropriate, disabling "turbo" mode may also be prudent. But it also makes sense to run with the system defaults to understand if your application exhibits any performance sensitivity to power management policies. The operating system power management sub-system typically control the P-state and C-states based on current and recent load. The scaling governor manages P-states. Operating systems often use adaptive policies that try to avoid deep C-states for some period if recent deep idle episodes proved to be very short and futile. This helps make the system more responsive under bursty or otherwise irregular load. But it also means the system is stateful and exhibits a memory effect, which can further complicate benchmarking. Forcing C0 + P0 should avoid this issue.

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• Pretty URL in ADF Faces of JDeveloper 11.1.2.2

  - by Frank Nimphius

  Many features planned for Oracle JDeveloper 12c find their way into current releases of Oracle JDeveloper 11g R1 and JDeveloper 11g R2. One example of such a feature is "pretty URL" - or "clean URL" as the Oracle JDeveloper 11g R2 (11.1.2.2) documentation puts it. "A.2.3.24 Clean URLs Historically, ADF Faces has used URL parameters to hold information, such as window IDs and state. However, URL parameters can prevent search engines from recognizing when URLs are actually the same, and therefore interfere with analytics. URL parameters can also interfere with bookmarking. By default, ADF Faces removes URL parameters using the HTML5 History Management API. If that API is unavailable, then session cookies are used.You can also manually configure how URL parameters are removed using the context parameter oracle.adf.view.rich.prettyURL.OPTIONS. Set the parameter to off so that no parameters are removed. Set the parameter to useHistoryApi to only use the HTML5 History Management API. If a browser does not support this API, then no parameters will be removed. Set the parameter to useCookies to use session cookies to remove parameters. If the browser does not support cookies, then no parameters will be removed." See: http://docs.oracle.com/cd/E26098_01/web.1112/e16181/ap_config.htm#ADFUI12856 So basically, what this part in the documentation says is: In JDeveloper 11g R2 (11.1.2.2), Oracle ADF Faces automatically removes its internally used dynamic parameters from the URL You can influence the setting with the prettyURL.OPTIONS context option, which however is not recommended you to do because the default behavior is able to detect if the browser client supports HTML 5 History management or not. In the latter case it the uses a session cookie and if this doesn't work, falls back to the "old" URL parameter adding. The information that is not so explicit and clearly mentioned in the documentation is that this is only for ADF Faces parameters (such as _afrLoop, Adf-Window-Id, etc.), but not the ADF controller token (_adf.ctrl-state)! Removing the ADF controller token is an enhancement request that will be implemented in Oracle JDeveloper 12c

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• JS closures - Passing a function to a child, how should the shared object be accessed

  - by slicedtoad

  I have a design and am wondering what the appropriate way to access variables is. I'll demonstrate with this example since I can't seem to describe it better than the title. Term is an object representing a bunch of time data (a repeating duration of time defined by a bunch of attributes) Term has some print functionality but does not implement the print functions itself, rather they are passed in as anonymous functions by the parent. This would be similar to how shaders can be passed to a renderer rather than defined by the renderer. A container (let's call it Box) has a Schedule object that can understand and use Term objects. Box creates Term objects and passes them to Schedule as required. Box also defines the print functions stored in Term. A print function usually takes an argument and uses it to return a string based on that argument and Term's internal data. Sometime the print function could also use data stored in Schedule, though. I'm calling this data shared. So, the question is, what is the best way to access this shared data. I have a lot of options since JS has closures and I'm not familiar enough to know if I should be using them or avoiding them in this case. Options: Create a local "reference" (term used lightly) to the shared data (data is not a primitive) when defining the print function by accessing the shared data through Schedule from Box. Example: var schedule = function(){ var sched = Schedule(); var t1 = Term( function(x){ // Term.print() return (x + sched.data).format(); }); }; Bind it to Term explicitly. (Pass it in Term's constructor or something). Or bind it in Sched after Box passes it. And then access it as an attribute of Term. Pass it in at the same time x is passed to the print function, (from sched). This is the most familiar way for my but it doesn't feel right given JS's closure ability. Do something weird like bind some context and arguments to print. I'm hoping the correct answer isn't purely subjective. If it is, then I guess the answer is just "do whatever works". But I feel like there are some significant differences between the approaches that could have a large impact when stretched beyond my small example.

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• Running C++ AMP kernels on the CPU

  - by Daniel Moth

  One of the FAQs we receive is whether C++ AMP can be used to target the CPU. For targeting multi-core we have a technology we released with VS2010 called PPL, which has had enhancements for VS 11 – that is what you should be using! FYI, it also has a Linux implementation via Intel's TBB which conforms to the same interface. When you choose to use C++ AMP, you choose to take advantage of massively parallel hardware, through accelerators like the GPU. Having said that, you can always use the accelerator class to check if you are running on a system where the is no hardware with a DirectX 11 driver, and decide what alternative code path you wish to follow.  In fact, if you do nothing in code, if the runtime does not find DX11 hardware to run your code on, it will choose the WARP accelerator which will run your code on the CPU, taking advantage of multi-core and SSE2 (depending on the CPU capabilities WARP also uses SSE3 and SSE 4.1 – it does not currently use AVX and on such systems you hopefully have a DX 11 GPU anyway). A few things to know about WARP It is our fallback CPU solution, not intended as a primary target of C++ AMP. WARP stands for Windows Advanced Rasterization Platform and you can read old info on this MSDN page on WARP. What is new in Windows 8 Developer Preview is that WARP now supports DirectCompute, which is what C++ AMP builds on. It is not currently clear if we will have a CPU fallback solution for non-Windows 8 platforms when we ship. When you create a WARP accelerator, its is_emulated property returns true. WARP does not currently support double precision.   BTW, when we refer to WARP, we refer to this accelerator described above. If we use lower case "warp", that refers to a bunch of threads that run concurrently in lock step and share the same instruction. In the VS 11 Developer Preview, the size of warp in our Ref emulator is 4 – Ref is another emulator that runs on the CPU, but it is extremely slow not intended for production, just for debugging. Comments about this post by Daniel Moth welcome at the original blog.

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• Multiple country-specific domains or one global domain [closed]

  - by CJM

  Possible Duplicate: How should I structure my urls for both SEO and localization? My company currently has its main (English) site on a .com domain with a .co.uk alias. In addition, we have separate sites for certain other countries - these are also hosted in the UK but are distinct sites with a country-specific domain names (.de, .fr, .se, .es), and the sites have differing amounts of distinct but overlapping content, For example, the .es site is entirely in Spanish and has a page for every section of the UK site but little else. Whereas the .de site has much more content (but still less than the UK site), in German, and geared towards our business focus in that country. The main point is that the content in the additional sites is a subset of the UK, is translated into the local language, and although sometimes is simply only a translated version of UK content, it is usually 'tweaked' for the local market, and in certain areas, contains unique content. The other sites get a fraction of the traffic of the UK site. This is perfectly understandable since the biggest chunk of work comes from the UK, and we've been established here for over 30 years. However, we are wanting to build up our overseas business and part of that is building up our websites to support this. The Question: I posed a suggestion to the business that we might consider consolidating all our websites onto the .com domain but with /en/de/fr/se/etc sections, as plenty of other companies seem to do. The theory was that the non-english sites would benefit from the greater reputation of the parent .com domain, and that all the content would be mutually supporting - my fear is that the child domains on their own are too small to compete on their own compared to competitors who are established in these countries. Speaking to an SEO consultant from my hosting company, he feels that this move would have some benefit (for the reasons mentioned), but they would likely be significantly outweighed by the loss of the benefits of localised domains. Specifically, he said that since the Panda update, and particularly the two sets of changes this year, that we would lose more than we would gain. Having done some Panda research since, I've had my eyes opened on many issues, but curiously I haven't come across much that mentions localised domain names, though I do question whether Google would see it as duplicated content. It's not that I disagree with the consultant, I just want to know more before I make recommendations to my company. What is the prevailing opinion in this case? Would I gain anything from consolidating country-specific content onto one domain? Would Google see this as duplicate content? Would there be an even greater penalty from the loss of country-specific domains? And is there anything else I can do to help support the smaller, country-specific domains?

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• Should I go back to college and graduate with a poor GPA or try to jump into an entry-level development position? [closed]

  - by jshin47

  I once attended a top-10 American university but I am currently not in school for several different reasons. Chief among them is that I did very poorly two semesters and even failed one of them (got two F's) which put me in automatic suspension. My major is not CS but math. I am in a pickle at the moment. After I was suspended I got a job at a niche IT company in the area. I am employed as something of an IT generalist; my primary responsibilities are Windows systems administration/networking but I also do some Android, iOS, and .NET development. I have released a few apps to the app store under my name and my company's name, and we have done work for a few big clients. I started working at my job about 1.5 years ago and I am somewhat happily employed but I do not see it as a long-term fit because it is a small company with little opportunity to advance. I would like to move out to California and particularly to the Bay Area to get a job at a more reputable or exciting company, even at a lower rate of pay, but I am not sure if I should do that or try to go back to school. If I went back to school, it would take 1-1.5 years to graduate and some $. Best case scenario I would graduate with a 2.9 or 3.0 GPA. It is a top-10 school, but that's a crappy GPA. If I do not go back to school, I will be a field where most people have degrees, without a degree. If anything goes wrong I could be really screwed as I feel I will get no respect without a degree. On the other hand I really would like to get started in the field and get more serious about developing good development practices, learning new languages/frameworks, and working with people who know a lot more than I so I can learn and grow as a developer and eventually do my own thing. Basically, I am wondering: Should I just go back to school? How much does the bad GPA / good school reputation weigh in? What about the fact that I am a Math major and not a CS major (have never taken a CS course)? Does my skill set as something of a generalist bode well for me finding work at a start up in the Bay Area? If not (2), should I hunker down and focus on producing a really good (or a few medicore) iOS apps? Android apps? etc... How would you look at someone who did great in HS, kind of goofed off in college and eventually quit, and got into development? Thanks for any thoughts or input.

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• Cloning a dual boot system from HDD to SSD

  - by Alex

  I'm planning on replacing my laptop's HDD with a 256GB SSD, but I have a dual-boot (12.04 and Windows 7) setup and I'd like to be able to directly migrate Ubuntu over without having to reinstall and lose all of my settings. GParted reports the following partition setup on my HDD. I am, of course, able to modify it if necessary. /dev/sda1 (NTFS) 66.92 out of 200.00 MB used I'm honestly not sure what this partition is for. Maybe for Windows 7 system files? I'm hesitant to mess with it. (edit; it turns out it is a partition for Windows recovery files in the event of OS corruption, so I don't want to remove it. Plus it also appears to be a major pain to remove anyways) /dev/sda2 (NTFS) 116.35 out of 339.06 GB used (boot) This partition is the C:/ drive on my Windows installation. I don't use it on my Ubuntu installation, except it is the boot partition and thus has grub on it. /dev/sda4 (extended) > /dev/sda5 (ext4) 14.49 out of 91.34 GB used > /dev/sda6 (linux-swap) 5.92 GB These are my Ubuntu partitions. /sda5 contains my documents and all of the files I use on Ubuntu, and (as far as I know) the system files for Ubuntu itself (it's the partition I created when prompted by the Live-DVD installer). /sda6 is, of course, the swap partition which I only need for hibernation (6GB of RAM). /dev/sda3 (NTFS) 9.89 out of 14.75 GB used This is an annoying partition that Lenovo created to store some drivers and files that I might need later on. For example, it allows me to use OneKeyRecovery for a quick factory recovery if absolutely necessary, not sure if that'll work on an SSD. It also contains not-so-important files for bloatware installation. In total, my HDD only has about 150GB of files on it so it should fit comfortably on the SSD. The problem is, I want to exactly migrate my files, partitions, OSes, MBR, etc. from my HDD to my SSD and I'm not quite sure how to do this. I've seen CloneZilla referenced before, but I'm not all too experienced and the documentation for it quite frankly seems a bit like a foreign language to me. So, put simply, is there any way I can exactly clone this HDD to an SSD without a massive headache? Also, if it matters, I'll probably be using an external hard drive case (as recommended in online tutorials) to externally attach the SSD to my laptop during the cloning process due to the lack of two hard drive slots in the machine.

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• SEO to ensure visibility for a narrow, non-competitive, non-commercial site

  - by hen3ry

  I'm webmaster of a non-commercial site in English. A non-native-English speaker asked me why our site doesn't produce hits in Google searches she conducts for relevant keywords in her native language. I asked her for a list of keywords in her native language, and I naively tried inserting those into the META info in the page headers and waited a couple of weeks. No help. A little searching informed me that Google doesn't use the META info, and has not done so for a very long time. D'oh! To be entirely concrete, suppose the StackExchange folks want Russian speakers to find this site, Pro Webmasters. The direct translation in Russian of "webmaster" --thanks, Google Translator-- is: "?????????". (Not sure this will render properly, but that's not essential to my question.) Assuming Pro Webmasters has a common template for all pages it generates, inserting "?????????" into the Keywords META for that template won't help, it seems. What could StackExchange do to make this site visible to users searching with the Russian keyword "?????????" ? Pretty much all the advice I've seen boils down to this, if I understand correctly: use the desired search term often (but not too often) among site content, and the problem will be solved. That's great, but I don't think sprinkling "?????????" visibly all over Pro Webmasters is going to fly. Just for completeness, crawlers must be long immune to the invisible-to-visitors scheme, e.g, format "?????????" in a tiny text size in a color the same as an existing background, e.g. white-over-white. Or, put that text inside a div styled: ' style="visibility: hidden" '. Probably some other equivalents. I can only think of one slightly effective method, along these lines: place an unobtrusive link on the common template to a page titled "for international users" , and on that page list desired synonyms for "webmaster" in various languages on that page. A test case --admittedly, just one-- using my site implies that a Google search for "international users" ????????? will produce a hit for this page, and thus make the site minimally visible, despite the fact that the page will almost never be visited. At the moment, anyway. Note: All the SEO discussions I have found so far are about competitive and --almost certainly-- commercial sites. To repeat: my site is non-commercial, and it is about an obscure, narrow topic that is of interest to only a small number of people worldwide. This isn't about clawing our way to the top of competitive rankings, just making this content minimally visible to interested non-native-English speakers. Ideas? TIA

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• Using HBase or Cassandra for a token server

  - by crippy

  I've been trying to figure out how to use HBase/Cassandra for a token system we're re-implementing. I can probably squeeze quite a lot more from MySQL, but it just seems it has come to clinging on to the wrong tool for the task just because we know it well. Eventually will hit a wall (like happened to us in other areas). Naturally I started looking into possible NoSQL solutions. The prominent ones (at least in terms of buzz) are HBase and Cassandra. The story is more or less like this: A user can send a gift other users. Each gift has a list of recipients or is public in which case limited by number or expiration date For each gift sent we generate some token that uniquely identifies that gift. For each gift we track the list of potential recipients and their current status relating to that gift (accepted, declinded etc). A user can request to see all his currently pending gifts A can request a list of users he has sent a gift to today (used to limit number of gifts sent) Required the ability to "dump" or "ignore" expired gifts (x day old gifts are considered expired) There are some other requirements but I believe the above covers the essentials. How would I go and model that using HBase or Cassandra? Well, the wall was performance. A few 10s of millions of records per day over 2 tables kept for 2 weeks (wish I could have kept it for more but there was no way). The response times kept getting slower and slower until eventually we had to start cutting down number of days we kept data. Caching helps here but it's not an ideal solution since a big part of the ops are updates. Also, as I hinted in my original post. We use MySQL extensively. We know exactly what it can and can't do both in naive implementations followed by native partitioning and finally by horizontally sharding our dataset on the application level to reside on multiple DB nodes. It can be done, but that's not really what I'm trying to get from this. I asked a very specific question about designing a solution using a NoSQL solution since it's very hard to find examples for designs out there. Brainlag, not trying to come off as rude. I actually appreciate it a lot that you are the only one who even bothered to respond. but I see it over and over again. People ask questions and others assume they have no idea what they're talking about and give an irrelevant answer. Ignore RDBMS please. The question is about nosql.

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• What algorithms can I use to detect if articles or posts are duplicates?

  - by michael

  I'm trying to detect if an article or forum post is a duplicate entry within the database. I've given this some thought, coming to the conclusion that someone who duplicate content will do so using one of the three (in descending difficult to detect): simple copy paste the whole text copy and paste parts of text merging it with their own copy an article from an external site and masquerade as their own Prepping Text For Analysis Basically any anomalies; the goal is to make the text as "pure" as possible. For more accurate results, the text is "standardized" by: Stripping duplicate white spaces and trimming leading and trailing. Newlines are standardized to \n. HTML tags are removed. Using a RegEx called Daring Fireball URLs are stripped. I use BB code in my application so that goes to. (ä)ccented and foreign (besides Enlgish) are converted to their non foreign form. I store information about each article in (1) statistics table and in (2) keywords table. (1) Statistics Table The following statistics are stored about the textual content (much like this post) text length letter count word count sentence count average words per sentence automated readability index gunning fog score For European languages Coleman-Liau and Automated Readability Index should be used as they do not use syllable counting, so should produce a reasonably accurate score. (2) Keywords Table The keywords are generated by excluding a huge list of stop words (common words), e.g., 'the', 'a', 'of', 'to', etc, etc. Sample Data text_length, 3963 letter_count, 3052 word_count, 684 sentence_count, 33 word_per_sentence, 21 gunning_fog, 11.5 auto_read_index, 9.9 keyword 1, killed keyword 2, officers keyword 3, police It should be noted that once an article gets updated all of the above statistics are regenerated and could be completely different values. How could I use the above information to detect if an article that's being published for the first time, is already existing within the database? I'm aware anything I'll design will not be perfect, the biggest risk being (1) Content that is not a duplicate will be flagged as duplicate (2) The system allows the duplicate content through. So the algorithm should generate a risk assessment number from 0 being no duplicate risk 5 being possible duplicate and 10 being duplicate. Anything above 5 then there's a good possibility that the content is duplicate. In this case the content could be flagged and linked to the article's that are possible duplicates and a human could decide whether to delete or allow. As I said before I'm storing keywords for the whole article, however I wonder if I could do the same on paragraph basis; this would also mean further separating my data in the DB but it would also make it easier for detecting (2) in my initial post. I'm thinking weighted average between the statistics, but in what order and what would be the consequences...

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• Why doesn't my texture display with this GLSL shader?

  - by Chewy Gumball

  I am trying to display a DXT1 compressed texture on a quad using a VBO and shaders, but I have been unable to get it working. All I get is a black square. I know my texture is uploaded properly because when I use immediate mode without shaders the texture displays fine but I will include that part just in case. Also, when I change the gl_FragColor to something like vec4 (0.0, 1.0, 1.0, 1.0) then I get a nice blue quad so I know that my shader is able to set the colour. It appears to be either the texture is not being bound correctly in the shader or the texture coordinates are not being picked up. However, I can't find the error! What am I doing wrong? I am using OpenTK in C# (not xna). Vertex Shader: void main() { gl_TexCoord[0] = gl_MultiTexCoord0; // Set the position of the current vertex gl_Position = gl_ModelViewProjectionMatrix * gl_Vertex; } Fragment Shader: uniform sampler2D diffuseTexture; void main() { // Set the output color of our current pixel gl_FragColor = texture2D(diffuseTexture, gl_TexCoord[0].st); //gl_FragColor = vec4 (0.0,1.0,1.0,1.0); } Drawing Code: int vb, eb; GL.GenBuffers(1, out vb); GL.GenBuffers(1, out eb); // Position Texture float[] verts = { 0.1f, 0.1f, 0.0f, 0.0f, 0.0f, 1.9f, 0.1f, 0.0f, 1.0f, 0.0f, 1.9f, 1.9f, 0.0f, 1.0f, 1.0f, 0.1f, 1.9f, 0.0f, 0.0f, 1.0f }; uint[] indices = { 0, 1, 2, 0, 2, 3 }; //upload data to the VBO GL.BindBuffer(BufferTarget.ArrayBuffer, vb); GL.BindBuffer(BufferTarget.ElementArrayBuffer, eb); GL.BufferData(BufferTarget.ArrayBuffer, (IntPtr)(verts.Length * sizeof(float)), verts, BufferUsageHint.StaticDraw); GL.BufferData(BufferTarget.ElementArrayBuffer, (IntPtr)(indices.Length * sizeof(uint)), indices, BufferUsageHint.StaticDraw); //Upload texture int buffer = GL.GenTexture(); GL.BindTexture(TextureTarget.Texture2D, buffer); GL.TexParameter(TextureTarget.Texture2D, TextureParameterName.TextureWrapS, (float)TextureWrapMode.Repeat); GL.TexParameter(TextureTarget.Texture2D, TextureParameterName.TextureWrapT, (float)TextureWrapMode.Repeat); GL.TexParameter(TextureTarget.Texture2D, TextureParameterName.TextureMagFilter, (float)TextureMagFilter.Linear); GL.TexParameter(TextureTarget.Texture2D, TextureParameterName.TextureMinFilter, (float)TextureMinFilter.Linear); GL.TexEnv(TextureEnvTarget.TextureEnv, TextureEnvParameter.TextureEnvMode, (float)TextureEnvMode.Modulate); GL.CompressedTexImage2D(TextureTarget.Texture2D, 0, texture.format, texture.width, texture.height, 0, texture.data.Length, texture.data); //Draw GL.UseProgram(shaderProgram); GL.EnableClientState(ArrayCap.VertexArray); GL.EnableClientState(ArrayCap.TextureCoordArray); GL.VertexPointer(3, VertexPointerType.Float, 5 * sizeof(float), 0); GL.TexCoordPointer(2, TexCoordPointerType.Float, 5 * sizeof(float), 3); GL.ActiveTexture(TextureUnit.Texture0); GL.Uniform1(GL.GetUniformLocation(shaderProgram, "diffuseTexture"), 0); GL.DrawElements(BeginMode.Triangles, indices.Length, DrawElementsType.UnsignedInt, 0);

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• Enum types, FlagAttribute & Zero value

  - by nmgomes

  We all know about Enums types and use them every single day. What is not that often used is to decorate the Enum type with the FlagsAttribute. When an Enum type has the FlagsAttribute we can assign multiple values to it and thus combine multiple information into a single enum. The enum values should be a power of two so that a bit set is achieved. Here is a typical Enum type: public enum OperationMode { /// <summary> /// No operation mode /// </summary> None = 0, /// <summary> /// Standard operation mode /// </summary> Standard = 1, /// <summary> /// Accept bubble requests mode /// </summary> Parent = 2 } In such scenario no values combination are possible. In the following scenario a default operation mode exists and combination is used: [Flags] public enum OperationMode { /// <summary> /// Asynchronous operation mode /// </summary> Async = 0, /// <summary> /// Synchronous operation mode /// </summary> Sync = 1, /// <summary> /// Accept bubble requests mode /// </summary> Parent = 2 } Now, it’s possible to do statements like: [DefaultValue(OperationMode.Async)] [TypeConverter(typeof(EnumConverter))] public OperationMode Mode { get; set; } /// <summary> /// Gets a value indicating whether this instance supports request from childrens. /// </summary> public bool IsParent { get { return (this.Mode & OperationMode.Parent) == OperationMode.Parent; } } or switch (this.Mode) { case OperationMode.Sync | OperationMode.Parent: Console.WriteLine("Sync,Parent"); break;[…]  But there is something that you should never forget: Zero is the absorber element for the bitwise AND operation. So, checking for OperationMode.Async (the Zero value) mode just like the OperationMode.Parent mode makes no sense since it will always be true: (this.Mode & 0x0) == 0x0 Instead, inverse logic should be used: OperationMode.Async = !OperationMode.Sync public bool IsAsync { get { return (this.Mode & ContentManagerOperationMode.Sync) != ContentManagerOperationMode.Sync; } } or public bool IsAsync { get { return (int)this.Mode == 0; } } Final Note: Benefits Allow multiple values combination The above samples snippets were taken from an ASP.NET control and enabled the following markup usage: <my:Control runat="server" Mode="Sync,Parent"> Drawback Zero value is the absorber element for the bitwise AND operation Be very carefully when evaluating the Zero value, either evaluate the enum value as an integer or use inverse logic.

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• Representing complex object dependencies

  - by max

  I have several classes with a reasonably complex (but acyclic) dependency graph. All the dependencies are of the form: class X instance contains an attribute of class Y. All such attributes are set during initialization and never changed again. Each class' constructor has just a couple parameters, and each object knows the proper parameters to pass to the constructors of the objects it contains. class Outer is at the top of the dependency hierarchy, i.e., no class depends on it. Currently, the UI layer only creates an Outer instance; the parameters for Outer constructor are derived from the user input. Of course, Outer in the process of initialization, creates the objects it needs, which in turn create the objects they need, and so on. The new development is that the a user who knows the dependency graph may want to reach deep into it, and set the values of some of the arguments passed to constructors of the inner classes (essentially overriding the values used currently). How should I change the design to support this? I could keep the current approach where all the inner classes are created by the classes that need them. In this case, the information about "user overrides" would need to be passed to Outer class' constructor in some complex user_overrides structure. Perhaps user_overrides could be the full logical representation of the dependency graph, with the overrides attached to the appropriate edges. Outer class would pass user_overrides to every object it creates, and they would do the same. Each object, before initializing lower level objects, will find its location in that graph and check if the user requested an override to any of the constructor arguments. Alternatively, I could rewrite all the objects' constructors to take as parameters the full objects they require. Thus, the creation of all the inner objects would be moved outside the whole hierarchy, into a new controller layer that lies between Outer and UI layer. The controller layer would essentially traverse the dependency graph from the bottom, creating all the objects as it goes. The controller layer would have to ask the higher-level objects for parameter values for the lower-level objects whenever the relevant parameter isn't provided by the user. Neither approach looks terribly simple. Is there any other approach? Has this problem come up enough in the past to have a pattern that I can read about? I'm using Python, but I don't think it matters much at the design level.

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• Why would more CPU cores on virtual machine slow compile times?

  - by Sid

  [edit#2] If anyone from VMWare can hit me up with a copy of VMWare Fusion, I'd be more than happy to do the same as a VirtualBox vs VMWare comparison. Somehow I suspect the VMWare hypervisor will be better tuned for hyperthreading (see my answer too) I'm seeing something curious. As I increase the number of cores on my Windows 7 x64 virtual machine, the overall compile time increases instead of decreasing. Compiling is usually very well suited for parallel processing as in the middle part (post dependency mapping) you can simply call a compiler instance on each of your .c/.cpp/.cs/whatever file to build partial objects for the linker to take over. So I would have imagined that compiling would actually scale very well with # of cores. But what I'm seeing is: 8 cores: 1.89 sec 4 cores: 1.33 sec 2 cores: 1.24 sec 1 core: 1.15 sec Is this simply a design artifact due to a particular vendor's hypervisor implementation (type2:virtualbox in my case) or something more pervasive across more VMs to make hypervisor implementations more simpler? With so many factors, I seem to be able to make arguments both for and against this behavior - so if someone knows more about this than me, I'd be curious to read your answer. Thanks Sid [edit:addressing comments] @MartinBeckett: Cold compiles were discarded. @MonsterTruck: Couldn't find an opensource project to compile directly. Would be great but can't screwup my dev env right now. @Mr Lister, @philosodad: Have 8 hw threads, using VirtualBox, so should be 1:1 mapping without emulation @Thorbjorn: I have 6.5GB for the VM and a smallish VS2012 project - it's quite unlikely that I'm swapping in/out trashing the page file. @All: If someone can point to an open source VS2010/VS2012 project, that might be a better community reference than my (proprietary) VS2012 project. Orchard and DNN seem to need environment tweaking to compile in VS2012. I really would like to see if someone with VMWare Fusion also sees this (for VMWare vs VirtualBox compartmentalization) Test details: Hardware: Macbook Pro Retina CPU : Core i7 @ 2.3Ghz (quad core, hyper threaded = 8 cores in windows task manager) Memory : 16 GB Disk : 256GB SSD Host OS: Mac OS X 10.8 VM type: VirtualBox 4.1.18 (type 2 hypervisor) Guest OS: Windows 7 x64 SP1 Compiler: VS2012 compiling a solution with 3 C# Azure projects Compile times measure by VS2012 plugin called 'VSCommands' All tests run 5 times, first 2 runs discarded, last 3 averaged

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• One Year Oracle SocialChat - The Movie

  - by mprove

  Tweet | Like | Watch on Vimeo You’ve just watched – hopefully – my first short movie. Thank you! Here is a bit of the back stage story. About 6 weeks ago colleagues from SNBC (Social Network and Business Collaboration) announced a Social Use Case Competition. It was expected to submit a video of 2 to 5 minutes duration on the Social Enterprise (our internal phrase for Enterprise 2.0). Hmm – I had a few vague ideas, but no script – no actors – no experience in film making. Really the best conditions to try something! I chose our weekly SocialChats as my main topic. But if you don’t do Danish Dogma cinema, you still need a script. Hence I played around with the SocialChat’s archive, and all of a sudden a script and even the actors appeared in front of me. The words that you have just seen are weekly topics. Slightly abridged and rearranged to form a story. Exciting, next phase. How to get it on digital celluloid? I have to confess I am still impressed by epic. (Keep in mind, epic was done in 2004.) And my actors – words – call for a typographic style already. The main part was done over a weekend with Apple Keynote. And I even found a wonderful matching soundtrack among my albums: Didge Goes World by Delago. I picked parts of Second Day and Seventh Day. Literally, the rhythm was set, and I "just" had to complete the movie. Tools used – apart from trial and error: Keynote, Pixelmator, GarageBand, iMovie. Finally I want to mention that I am extremely thankful to BSC Music for granting permissions to use the tracks for this short film! Without this sound it would have been just an ordinary slide show. – Internal note: The next SocialChat is on Death by PowerPoint vs. Presentation Zen. CU this Friday 3pm Greenwich / 7am Pacific.

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• At $20/month Windows Azure host my website with 99.97% uptime

  - by Gopinath

  Couple of years ago a reliable and decent performing Windows hosting was not affordable to many enthusiastic developers who want to try a startup idea or build a hobby site. I tried to start an ASP.NET website few years ago to provide services like – Mobile Tracing, Vehicle Tracing. But due to high cost of Windows hosting I developed those services using PHP (not an easy task for .NET developer) and hosted on them Linux servers.  But with recent evolution of Windows Azure, hosting ASP.NET websites on highly reliable servers is affordable. Today anyone can host a high responsive and available ASP.NET website for just $20/month using Windows Azure. My website coziie.com is running on Windows Azure and serves close to quarter millions visitors a month with 99.97% of uptime and most of the page load times are less than 3 seconds. All I spend to run this website is just around $20, if you translate it to India rupees its roughly Rs.1000. The web sever of coziie.com is powered by a single Extra Small Web role instance and the backend is powered by a SQL Azure instance. Azure is quite impressive to provide 99.97% of uptime. Response times during peak are around 3 seconds and on nomarl loads it is around 1.5 seconds. Here is the report of uptime provided by Royal Pingdom over last one year For just $20/month Windows Azure takes care of the following apart from hosting Patches up Windows OS to the latest version Upgrades ASP.NET to the latest version – coziie.com is running on ASP.NET MVC 3 and soon I’ll upgrade it to ASP.NET MVC 4 Hosts data on latest and best version Sql Server database SQL Azure maintains 3 copies of database and automatically recovers in case of server failures and disasters. I never worry about database backups/restore. Provides staging environment for deploying applications for testing purpose and move them to production – I upgrade  twice a month on average With Windows Azure I no longer focus on server maintenance or data backups. They are taken up by Microsoft team and I just focus on building my website. Wish there is a low cost Linux version of Windows Azure so that I can stop worrying about server maintenance of this blog!! If you are looking for a Windows hosting, look no further than Windows Azure. If you find $20/month is a bit expensive to start with you may explore Azure Website (sort of shared hosted environment) which is free to start with and as your traffic grows you can move to paid hosting.

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• Real-Time Multi-User Gaming Platform

  - by Victor Engel

  I asked this question at Stack Overflow but was told it's more appropriate here, so I'm posting it again here. I'm considering developing a real-time multi-user game, and I want to gather some information about possibilities before I do some real development. I've thought about how best to ask the question, and for simplicity, the best way that occurred to me was to make an analogy to the field (or playground) game darebase. In the field game of darebase, there are two or more bases. To start, there is one team on each base. The game is a fancy game of tag. When two people meet out in the field, the person who left his base most recently timewise captures the other person. They then return to that person's base. Play continues until everyone is part of the same team. So, analogizing this to an online computer game, let's suppose there are an indefinite number of bases. When a person starts up the game, he has a team that is located at, for example, his current GPS coordinates. It could be a virtual world, but for sake of argument, let's suppose the virtual world corresponds to the player's actual GPS coordinates. The game software then consults the database to see where the closest other base is that is online, and the two teams play their game of virtual tag. Note that the user of the other base could have a different base than the one run by the current user as the closest base to him, in which case, he would be in two simultaneous battles, one with each base. When they go offline, the state of their players is saved on a server somewhere. Game logic calls for the players to have some automaton-logic of some sort, so they can fend for themselves in a limited way using basic rules, until their user goes online again. The user doesn't control the players' movements directly, but issues general directives that influence the players' movement logic. I think this analogy is good enough to frame my question. What sort of platforms are available to develop this sort of game? I've been looking at smartfoxserver, but I'm not convinced yet that it is the best option or even that it will work at all. One possibility, of course, would be to roll out my own web server, but I'd rather not do that if there is an existing service out there already that I could tap into. I will be developing for iOS devices at first. So any suggestions would be greatly appreciated. I think I need to establish the architecture first before proceeding with this project. Note that darbase is not the game I intend to implement, but, upon reflection, that might not be a bad idea either.

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• Oracle Partner Architects Training

  - by mseika

  Dear Oracle Partner, There is a lot more to Oracle technology than meets the eye. Sure, you already belong to a small circle of our most experienced and committed partners. But are you making the best use possible of our technology solutions? Put it to the test.  Join the “Oracle Partner Architects Training”. It is aimed at providing your experts, architects and consultants with in-depth architectural knowledge about Oracle technology. Here is your chance to learn from the best. Seasoned speakers, exclusive content and no product marketing. Oracle technology beyond the obvious. Choose from any of the 40 recorded training sessions. Topics include:  • Security• Service integration • Database and options• Data integration • BI and applications• Applications and infrastructure• Hardware and software combinations The market and Oracle value specialized partners More information about specialization can be found on opn.oracle.com. Click through to OPN Program/Specialize “What’s in it for us?” Quite simply: the opportunity to gain the differentiation and competitive edge you need to stand out in the marketplace. • Differentiate your company through expertise in leading Oracle IT solutions;• Get your experts, architects and consultants up to speed on specialized services and solutions;• Make our customers’ shortlists. They are looking for value-added solutions for their business.   Recordings All sessions are recorded. After registering for a session in oraevents, you will receive the info to access the webex recording. Your timing, your tempo.  Registration and more information Visit architects.oraevents.eu to sign up for the recorded sessions. NOTE: Looking to get your consultants Oracle certified? One more reason to join the Oracle Partner Architects Training. It is the fast track to getting their expertise validated with an Oracle certificate. Training schedule  Choose from any of the 40 recorded training sessions: SECURITY THE PRACTICAL APPROACH •  Identity governance• Access management• Data privacy and protection• End-to-end security, layers of exposures•  Identity & access management, why and where to start?• Data security, how? SERVICE INTEGRATION A NEW ROADTO ENTERPRISE-WIDE SERVICE INTEGRATION • Oracle RUEI: maximize business value by insight into real end-user experiences•  Governance challenges in the services landscape•  Creating an agile enterprise (by Jeff Davies)• Oracle’s approach to SOA (by Jeff Davies) - guiding and accelerating SOA success• Technical case study – the SOA challenge• Oracle’s unified business process management suite 11g (incl. demo) DATABASE DATABASE AND OPTIONS, GOINGWIDE •  Understanding service level agreements for databases• Database lifecycle management• Data centric information lifecycle management DATA INTEGRATION  DIS FOR ARCHITECTS • Data integration solutions: an overview• ODI and goldengate• Data quality

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• LWJGL - Mixing 2D and 3D

  - by nathan

  I'm trying to mix 2D and 3D using LWJGL. I have wrote 2D little method that allow me to easily switch between 2D and 3D. protected static void make2D() { glEnable(GL_BLEND); GL11.glMatrixMode(GL11.GL_PROJECTION); GL11.glLoadIdentity(); glOrtho(0.0f, SCREEN_WIDTH, SCREEN_HEIGHT, 0.0f, 0.0f, 1.0f); GL11.glMatrixMode(GL11.GL_MODELVIEW); GL11.glLoadIdentity(); } protected static void make3D() { glDisable(GL_BLEND); GL11.glMatrixMode(GL11.GL_PROJECTION); GL11.glLoadIdentity(); // Reset The Projection Matrix GLU.gluPerspective(45.0f, ((float) SCREEN_WIDTH / (float) SCREEN_HEIGHT), 0.1f, 100.0f); // Calculate The Aspect Ratio Of The Window GL11.glMatrixMode(GL11.GL_MODELVIEW); glLoadIdentity(); } The in my rendering code i would do something like: make2D(); //draw 2D stuffs here make3D(); //draw 3D stuffs here What i'm trying to do is to draw a 3D shape (in my case a quad) and i 2D image. I found this example and i took the code from TextureLoader, Texture and Sprite to load and render a 2D image. Here is how i load the image. TextureLoader loader = new TextureLoader(); Sprite s = new Sprite(loader, "player.png") And how i render it: make2D(); s.draw(0, 0); It works great. Here is how i render my quad: glTranslatef(0.0f, 0.0f, 30.0f); glScalef(12.0f, 9.0f, 1.0f); DrawUtils.drawQuad(); Once again, no problem, the quad is properly rendered. DrawUtils is a simple class i wrote containing utility method to draw primitives shapes. Now my problem is when i want to mix both of the above, loading/rendering the 2D image, rendering the quad. When i try to load my 2D image with the following: s = new Sprite(loader, "player.png); My quad is not rendered anymore (i'm not even trying to render the 2D image at this point). Only the fact of creating the texture create the issue. After looking a bit at the code of Sprite and TextureLoader i found that the problem appears after the call of the glTexImage2d. In the TextureLoader class: glTexImage2D(target, 0, dstPixelFormat, get2Fold(bufferedImage.getWidth()), get2Fold(bufferedImage.getHeight()), 0, srcPixelFormat, GL_UNSIGNED_BYTE, textureBuffer); Commenting this like make the problem disappear. My question is then why? Is there anything special to do after calling this function to do 3D? Does this function alter the render part, the projection matrix?

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• How to resolve concurrent ramp collisions in 2d platformer?

  - by Shaun Inman

  A bit about the physics engine: Bodies are all rectangles. Bodies are sorted at the beginning of every update loop based on the body-in-motion's horizontal and vertical velocity (to avoid sticky walls/floors). Solid bodies are resolved by testing the body-in-motion's new X with the old Y and adjusting if necessary before testing the new X with the new Y, again adjusting if necessary. Works great. Ramps (rectangles with a flag set indicating bottom-left, bottom-right, etc) are resolved by calculating the ratio of penetration along the x-axis and setting a new Y accordingly (with some checks to make sure the body-in-motion isn't attacking from the tall or flat side, in which case the ramp is treated as a normal rectangle). This also works great. Side-by-side ramps, eg. \/ and /\, work fine but things get jittery and unpredictable when a top-down ramp is directly above a bottom-up ramp, eg. < or > or when a bottom-up ramp runs right up to the ceiling/top-down ramp runs right down to the floor. I've been able to lock it down somewhat by detecting whether the body-in-motion hadFloor when also colliding with a top-down ramp or hadCeiling when also colliding with a bottom-up ramp then resolving by calculating the ratio of penetration along the y-axis and setting the new X accordingly (the opposite of the normal behavior). But as soon as the body-in-motion jumps the hasFloor flag becomes false, the first ramp resolution pushes the body into collision with the second ramp and collision resolution becomes jittery again for a few frames. I'm sure I'm making this more complicated than it needs to be. Can anyone recommend a good resource that outlines the best way to address this problem? (Please don't recommend I use something like Box2d or Chipmunk. Also, "redesign your levels" isn't an answer; the body-in-motion may at times be riding another body-in-motion, eg. a platform, that pushes it into a ramp so I'd like to be able to resolve this properly.) Thanks!

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• What Counts for a DBA: Passion

  - by drsql

  One of my first questions, when interviewing for a DBA/Programmer position, is always: “Why do you want this job?” The answers I receive range from cheesy hyperbole (“I want to enhance your services with my vast knowledge”) to deadpan realism (“I have N kids who all have a hole in the front of their face where food goes"). Both answers are fine in their own way, at least displaying some self-confidence, humour and honesty, but once in a while, I'll hear the answer that is music to me ears... “I LOVE DATABASES!” Whenever I hear it, my nerves tingle in hopeful anticipation; have I found someone for whom working with database isn't just a job, but a passion? Inevitably, I'm often disappointed. What initially seemed like passion turns out to be rather shallow enthusiasm; the person is enthusiastic about working with databases in the same way he or she might be about eating a bag of Cajun spiced kettle chips; enjoyable, but not something to think about too deeply or take too seriously. Enthusiasm comes, and enthusiasm goes. I've seen countless technical forum users burst onto the scene in a blaze of frantic question-answering, only to fade away within days, never to be heard from again. Passion, however, is more of a longstanding commitment. The biographies of the great technologists and authors of the recent past are full of the sort of passion and engrossment that lead a person to write a novel non-stop for a fortnight with no sleep and only dog food to eat (Philip K. Dick), or refuse to leave the works of the first tunnel under the Thames, even though it was flooded (Brunel). In a similar (though more modest) way, my passion for working with databases has led me to acts that might cause someone for whom it was "just a job" to roll their eyes in disbelief. Most evenings you're more likely to find me reading a database book than watching TV. I've spent hundreds of hours of my spare time writing blogs and articles (some of which are only read by tens of people); I've spent hundreds of dollars travelling to conferences, paying my own flight and hotel expenses, so that I can share a little of what I know, and mix with some like-minded people. And I know I'm far from alone in this, in the SQL Server community. Passion isn't everything, of course, and it isn't always accompanied by any great skill, but in almost every case, that skill can be cultivated over time. If you are doing what you are passionate about, work turns into more than just a way to feed your kids; it becomes your hobby, entertainment, and preoccupation. And it is this passion that gives a DBA the obsessive stubbornness, the refusal to be beaten by even the most difficult problem, which is often so crucial. A final word of warning though: passion without limits can turn weird. Never let it get in the way of your wife, kids, bills, or personal hygiene.

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