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• NetBeans, JSF, and MySQL Primary Keys using AUTO_INCREMENT

  - by MarkH

  I recently had the opportunity to spin up a small web application using JSF and MySQL. Having developed JSF apps with Oracle Database back-ends before and possessing some small familiarity with MySQL (sans JSF), I thought this would be a cakewalk. Things did go pretty smoothly...but there was one little "gotcha" that took more time than the few seconds it really warranted. The Problem Every DBMS has its own way of automatically generating primary keys, and each has its pros and cons. For the Oracle Database, you use a sequence and point your Java classes to it using annotations that look something like this: @GeneratedValue(strategy=GenerationType.SEQUENCE, generator="POC_ID_SEQ") @SequenceGenerator(name="POC_ID_SEQ", sequenceName="POC_ID_SEQ", allocationSize=1) Between creating the actual sequence in the database and making sure you have your annotations right (watch those typos!), it seems a bit cumbersome. But it typically "just works", without fuss. Enter MySQL. Designating an integer-based field as PRIMARY KEY and using the keyword AUTO_INCREMENT makes the same task seem much simpler. And it is, mostly. But while NetBeans cranks out a superb "first cut" for a basic JSF CRUD app, there are a couple of small things you'll need to bring to the mix in order to be able to actually (C)reate records. The (RUD) performs fine out of the gate. The Solution Omitting all design considerations and activity (!), here is the basic sequence of events I followed to create, then resolve, the JSF/MySQL "Primary Key Perfect Storm": Fire up NetBeans. Create JSF project. Create Entity Classes from Database. Create JSF Pages from Entity Classes. Test run. Try to create record and hit error. It's a simple fix, but one that was fun to find in its completeness. :-) Even though you've told it what to do for a primary key, a MySQL table requires a gentle nudge to actually generate that new key value. Two things are needed to make the magic happen. First, you need to ensure the following annotation is in place in your Java entity classes: @GeneratedValue(strategy = GenerationType.IDENTITY) All well and good, but the real key is this: in your controller class(es), you'll have a create() function that looks something like this, minus the comment line and the setId() call in bold red type:     public String create() {         try {             // Assign 0 to ID for MySQL to properly auto_increment the primary key.             current.setId(0);             getFacade().create(current);             JsfUtil.addSuccessMessage(ResourceBundle.getBundle("/Bundle").getString("CategoryCreated"));             return prepareCreate();         } catch (Exception e) {             JsfUtil.addErrorMessage(e, ResourceBundle.getBundle("/Bundle").getString("PersistenceErrorOccured"));             return null;         }     } Setting the current object's primary key attribute to zero (0) prior to saving it tells MySQL to get the next available value and assign it to that record's key field. Short and simple…but not inherently obvious if you've never used that particular combination of NetBeans/JSF/MySQL before. Hope this helps! All the best, Mark

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• To My 24 Year Old Self, Wherever You Are&hellip;

  - by D'Arcy Lussier

  A decade is a milestone in one’s life, regardless of when it occurs. 2011 might seem like a weird year to mark a decade, but 2001 was a defining year for me. It marked my emergence into the technology industry, an unexpected loss of innocence, and triggered an ongoing struggle with faith and belief. Once you go through a valley, climbing the mountain and looking back over where you travelled, you can take in the entirety of the journey. Over the last 10 years I kept journals, and in this new year I took some time to review them. For those today that are me a decade ago, I share with you what I’ve gleamed from my experiences. Take it for what it’s worth, and safe travels on your own journeys through life. Life is a Performance-Based Sport Have confidence, believe you’re capable, but realize that life is a performance-based sport. Everything you get in life is based on whether you can show that you deserve it. Performance is also your best defense against personal attacks. Just make sure you know what standards you’re expected to hit and if people want to poke holes at you let them do the work of trying to find them. Sometimes performance won’t matter though. Good things will happen to bad people, and bad things to good people. What’s important is that you do the right things and ensure the good and bad even out in your own life. How you finish is just as important as how you start. Start strong, end strong. Respect is Your Most Prized Reward Respect is more important than status or ego. The formula is simple: Performing Well + Building Trust + Showing Dedication = Respect Focus on perfecting your craft and helping your team and respect will come. Life is a Team Sport Whatever aspect of your life, you can’t do it alone. You need to rely on the people around you and ensure you’re a positive aspect of their lives; even those that may be difficult or unpleasant. Avoid criticism and instead find ways to help colleagues and superiors better whatever environment you’re in (work, home, etc.). Don’t just highlight gaps and issues, but also come to the table with solutions. At the same time though, stand up for yourself and hold others accountable for the commitments they make to the team. A healthy team needs accountability. Give feedback early and often, and make it verbal. Issues should be dealt with immediately, and positives should be celebrated as they happen. Life is a Contact Sport Difficult moments will happen. Don’t run from them or shield yourself from experiencing them. Embrace them. They will further mold you and reveal who you will become. Find Your Tribe and Embrace Your Community We all need a tribe: a group of people that we gravitate to for support, guidance, wisdom, and friendship. Discover your tribe and immerse yourself in them. Don’t look for a non-existent tribe just to fill the need of belonging though that will leave you empty and bitter when they don’t meet your unrealistic expectations. Try to associate with people more experienced and more knowledgeable than you. You’ll always learn, and you’ll always remember you have much to learn. Put yourself out there, get involved with the community. Opportunities will present themselves. When we open ourselves up to be vulnerable, we also give others the chance to do the same. This helps us all to grow and help each other, it’s very important. And listen to your wife. (Easter *is* a romantic holiday btw, regardless of what you may think.) Don’t Believe Your Own Press Clippings (and by that I mean the ones you write) Until you have a track record of performance to refer to, any notions of grandeur are just that: notions. You lose your rookie status through trials and tribulations, not by the number of stamps in your passport. Be realistic about your own “experience and leadership” and be honest when you aren’t ready for something. And always remember: nobody really cares about you as much as you think they do. Don’t Let Assholes Get You Down The world isn’t evil, but there is evil in the world. Know the difference and don’t paint all people with the same brush. Do be wary of those that use personal beliefs to describe their business (i.e. “We’re a [religion] company”). What matters is the culture of the organization, and that will tell you the moral compass and what is truly valued. Don’t make someone or something a priority that only makes you an option. Life is unfair and enemies/opponents will succeed when you fail. Don’t waste your energy getting upset at this; the only one that will lose out is you. As mentioned earlier, nobody really cares about you as much as you think they do. Misc Ecclesiastes is bullshit. Everything is certainly *not* meaningless. Software development is about delivery, not the process. Having a great process means nothing if you don’t produce anything. Watch “The Weatherman” (“It’s not easy, but easy doesn’t enter into grownup life.”). Read Tony Dungee’s autobiography, even if you don’t like football, and even if you aren’t a Christian. Say no, don’t feel like you have to commit right away when someone asks you to.

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• Computer Networks UNISA - Chap 8 &ndash; Wireless Networking

  - by MarkPearl

  After reading this section you should be able to Explain how nodes exchange wireless signals Identify potential obstacles to successful transmission and their repercussions, such as interference and reflection Understand WLAN architecture Specify the characteristics of popular WLAN transmission methods including 802.11 a/b/g/n Install and configure wireless access points and their clients Describe wireless MAN and WAN technologies, including 802.16 and satellite communications The Wireless Spectrum All wireless signals are carried through the air by electromagnetic waves. The wireless spectrum is a continuum of the electromagnetic waves used for data and voice communication. The wireless spectrum falls between 9KHZ and 300 GHZ. Characteristics of Wireless Transmission Antennas Each type of wireless service requires an antenna specifically designed for that service. The service’s specification determine the antenna’s power output, frequency, and radiation pattern. A directional antenna issues wireless signals along a single direction. An omnidirectional antenna issues and receives wireless signals with equal strength and clarity in all directions The geographical area that an antenna or wireless system can reach is known as its range Signal Propagation LOS (line of sight) uses the least amount of energy and results in the reception of the clearest possible signal. When there is an obstacle in the way, the signal may… pass through the object or be obsrobed by the object or may be subject to reflection, diffraction or scattering. Reflection – waves encounter an object and bounces off it. Diffraction – signal splits into secondary waves when it encounters an obstruction Scattering – is the diffusion or the reflection in multiple different directions of a signal Signal Degradation Fading occurs as a signal hits various objects. Because of fading, the strength of the signal that reaches the receiver is lower than the transmitted signal strength. The further a signal moves from its source, the weaker it gets (this is called attenuation) Signals are also affected by noise – the electromagnetic interference) Interference can distort and weaken a wireless signal in the same way that noise distorts and weakens a wired signal. Frequency Ranges Older wireless devices used the 2.4 GHZ band to send and receive signals. This had 11 communication channels that are unlicensed. Newer wireless devices can also use the 5 GHZ band which has 24 unlicensed bands Narrowband, Broadband, and Spread Spectrum Signals Narrowband – a transmitter concentrates the signal energy at a single frequency or in a very small range of frequencies Broadband – uses a relatively wide band of the wireless spectrum and offers higher throughputs than narrowband technologies The use of multiple frequencies to transmit a signal is known as spread-spectrum technology. In other words a signal never stays continuously within one frequency range during its transmission. One specific implementation of spread spectrum is FHSS (frequency hoping spread spectrum). Another type is known as DSS (direct sequence spread spectrum) Fixed vs. Mobile Each type of wireless communication falls into one of two categories Fixed – the location of the transmitted and receiver do not move (results in energy saved because weaker signal strength is possible with directional antennas) Mobile – the location can change WLAN (Wireless LAN) Architecture There are two main types of arrangements Adhoc – data is sent directly between devices – good for small local devices Infrastructure mode – a wireless access point is placed centrally, that all devices connect with 802.11 WLANs The most popular wireless standards used on contemporary LANs are those developed by IEEE’s 802.11 committee. Over the years several distinct standards related to wireless networking have been released. Four of the best known standards are also referred to as Wi-Fi. They are…. 802.11b 802.11a 802.11g 802.11n These four standards share many characteristics. i.e. All 4 use half duplex signalling Follow the same access method Access Method 802.11 standards specify the use of CSMA/CA (Carrier Sense Multiple Access with Collision Avoidance) to access a shared medium. Using CSMA/CA before a station begins to send data on an 802.11 network, it checks for existing wireless transmissions. If the source node detects no transmission activity on the network, it waits a brief period of time and then sends its transmission. If the source does detect activity, it waits a brief period of time before checking again. The destination node receives the transmission and, after verifying its accuracy, issues an acknowledgement (ACT) packet to the source. If the source receives the ACK it assumes the transmission was successful, – if it does not receive an ACK it assumes the transmission failed and sends it again. Association Two types of scanning… Active – station transmits a special frame, known as a prove, on all available channels within its frequency range. When an access point finds the probe frame, it issues a probe response. Passive – wireless station listens on all channels within its frequency range for a special signal, known as a beacon frame, issued from an access point – the beacon frame contains information necessary to connect to the point. Re-association occurs when a mobile user moves out of one access point’s range and into the range of another. Frames Read page 378 – 381 about frames and specific 802.11 protocols Bluetooth Networks Sony Ericson originally invented the Bluetooth technology in the early 1990s. In 1998 other manufacturers joined Ericsson in the Special Interest Group (SIG) whose aim was to refine and standardize the technology. Bluetooth was designed to be used on small networks composed of personal communications devices. It has become popular wireless technology for communicating among cellular telephones, phone headsets, etc. Wireless WANs and Internet Access Refer to pages 396 – 402 of the textbook for details.

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• Oracle NoSQL Database Exceeds 1 Million Mixed YCSB Ops/Sec

  - by Charles Lamb

  We ran a set of YCSB performance tests on Oracle NoSQL Database using SSD cards and Intel Xeon E5-2690 CPUs with the goal of achieving 1M mixed ops/sec on a 95% read / 5% update workload. We used the standard YCSB parameters: 13 byte keys and 1KB data size (1,102 bytes after serialization). The maximum database size was 2 billion records, or approximately 2 TB of data. We sized the shards to ensure that this was not an "in-memory" test (i.e. the data portion of the B-Trees did not fit into memory). All updates were durable and used the "simple majority" replica ack policy, effectively 'committing to the network'. All read operations used the Consistency.NONE_REQUIRED parameter allowing reads to be performed on any replica. In the past we have achieved 100K ops/sec using SSD cards on a single shard cluster (replication factor 3) so for this test we used 10 shards on 15 Storage Nodes with each SN carrying 2 Rep Nodes and each RN assigned to its own SSD card. After correcting a scaling problem in YCSB, we blew past the 1M ops/sec mark with 8 shards and proceeded to hit 1.2M ops/sec with 10 shards.  Hardware Configuration We used 15 servers, each configured with two 335 GB SSD cards. We did not have homogeneous CPUs across all 15 servers available to us so 12 of the 15 were Xeon E5-2690, 2.9 GHz, 2 sockets, 32 threads, 193 GB RAM, and the other 3 were Xeon E5-2680, 2.7 GHz, 2 sockets, 32 threads, 193 GB RAM.  There might have been some upside in having all 15 machines configured with the faster CPU, but since CPU was not the limiting factor we don't believe the improvement would be significant. The client machines were Xeon X5670, 2.93 GHz, 2 sockets, 24 threads, 96 GB RAM. Although the clients had 96 GB of RAM, neither the NoSQL Database or YCSB clients require anywhere near that amount of memory and the test could have just easily been run with much less. Networking was all 10GigE. YCSB Scaling Problem We made three modifications to the YCSB benchmark. The first was to allow the test to accommodate more than 2 billion records (effectively int's vs long's). To keep the key size constant, we changed the code to use base 32 for the user ids. The second change involved to the way we run the YCSB client in order to make the test itself horizontally scalable.The basic problem has to do with the way the YCSB test creates its Zipfian distribution of keys which is intended to model "real" loads by generating clusters of key collisions. Unfortunately, the percentage of collisions on the most contentious keys remains the same even as the number of keys in the database increases. As we scale up the load, the number of collisions on those keys increases as well, eventually exceeding the capacity of the single server used for a given key.This is not a workload that is realistic or amenable to horizontal scaling. YCSB does provide alternate key distribution algorithms so this is not a shortcoming of YCSB in general. We decided that a better model would be for the key collisions to be limited to a given YCSB client process. That way, as additional YCSB client processes (i.e. additional load) are added, they each maintain the same number of collisions they encounter themselves, but do not increase the number of collisions on a single key in the entire store. We added client processes proportionally to the number of records in the database (and therefore the number of shards). This change to the use of YCSB better models a use case where new groups of users are likely to access either just their own entries, or entries within their own subgroups, rather than all users showing the same interest in a single global collection of keys. If an application finds every user having the same likelihood of wanting to modify a single global key, that application has no real hope of getting horizontal scaling. Finally, we used read/modify/write (also known as "Compare And Set") style updates during the mixed phase. This uses versioned operations to make sure that no updates are lost. This mode of operation provides better application behavior than the way we have typically run YCSB in the past, and is only practical at scale because we eliminated the shared key collision hotspots.It is also a more realistic testing scenario. To reiterate, all updates used a simple majority replica ack policy making them durable. Scalability Results In the table below, the "KVS Size" column is the number of records with the number of shards and the replication factor. Hence, the first row indicates 400m total records in the NoSQL Database (KV Store), 2 shards, and a replication factor of 3. The "Clients" column indicates the number of YCSB client processes. "Threads" is the number of threads per process with the total number of threads. Hence, 90 threads per YCSB process for a total of 360 threads. The client processes were distributed across 10 client machines. Shards KVS Size Clients Mixed (records) Threads OverallThroughput(ops/sec) Read Latencyav/95%/99%(ms) Write Latencyav/95%/99%(ms) 2 400m(2x3) 4 90(360) 302,152 0.76/1/3 3.08/8/35 4 800m(4x3) 8 90(720) 558,569 0.79/1/4 3.82/16/45 8 1600m(8x3) 16 90(1440) 1,028,868 0.85/2/5 4.29/21/51 10 2000m(10x3) 20 90(1800) 1,244,550 0.88/2/6 4.47/23/53

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• Webcor Builders Coordinates Construction Schedules and Mitigates Potential Delays More Efficiently with Integrated Project Management

  - by Sylvie MacKenzie, PMP

  Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:"Times New Roman","serif";} With more than 40 years of commercial construction experience, Webcor Builders is a leading builder of distinguished, high-profile projects, including high-rise condominiums and hotels, laboratories, healthcare centers, and public works projects. Webcor is also known for its award-winning concrete, interior construction, historic restoration, and seismic renovation work. The company has completed more than 50 million square feet of projects to date. Considering the variety and complexity of the construction projects Webcor undertakes, an integrated project management solution is critical to ensuring optimal efficiency and completing client projects on time and on budget. The company previously used a number of scheduling systems for its various building projects. These packages provided different levels of schedule detail and required schedulers, engineers, and other employees to learn multiple systems. From an IT cost and complexity perspective, the company had to manage multiple scheduling systems and pay for multiple sets of licenses. The company looked to standardize on an enterprise project management system, and selected Oracle’s Primavera P6 Enterprise Project Portfolio Management. Webcor uses the solution’s advanced capabilities to schedule complex projects, analyze delays, model and propose multiple scenarios to demonstrate and mitigate delays and cost overruns, and process that information efficiently to deliver the scheduling precision that public and private projects require. In fact, the solution was instrumental in helping the company’s expansion into public sector projects during the recent economic downturn, and with Primavera P6 in place, it can deliver the precise schedule reporting required for large public projects. With Primavera P6 in place, the company could deliver the precise scheduling and milestone reporting capabilities required for large public projects. The solution is in managing the high-profile University of California – Berkeley Memorial Stadium project. Webcor was hired as construction manager and general contractor for the stadium renovation project, which is a fast-paced project located near the seismically active Hayward Fault Zone. Due to the University of California’s football schedule, meeting the Universities deadline for the coming season placed Webcor in a situation where risk awareness and early warnings of issues would be paramount. Webcor and the extended project team needed a solution that could instantly analyze alternate scenarios to mitigate potential delays; Primavera would deliver those answers.The team would also need to enable multiple stakeholders to use an internet-based platform to access the schedule from various locations, and model complicated sequencing requirements where swift decisions would be made to keep the project on track. The schedule is an integral part of Webcor’s construction management process for the stadium project. Rather than providing the client with the industry-standard monthly update, Webcor updates the critical path method (CPM) schedule on a weekly basis. The project team also reviews the schedule and updates weekly to confirm that progress and forecasted performance are accurate. Hired by the University for their ability to deliver in high risk environments The Webcor team was hit recently with a design supplement that could have added up to 70 days to the project. Using Oracle Primavera P6 the team sprung into action analyzing multiple “what if” scenarios to review mitigation means and methods.  Determined to make sure the Bears could take the field in the coming season the project team nearly eliminated the impact with their creative analysis in working the schedule. The total time from the issuance of the final design supplement to an agreed mitigation response was less than one week; leveraging the Oracle Primavera solution Webcor was able to deliver superior customer value With the ability to efficiently manage projects and schedules, Webcor can ensure it completes its projects on time and on budget, as well as inform clients about what changes to plans will mean in terms of delays and additional costs. Read the complete customer case study at :  http://www.oracle.com/us/corporate/customers/customersearch/webcor-builders-1-primavera-ss-1639886.html

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• What Counts for a DBA: Humility

  - by drsql

  In football (the American sort, naturally,) there are a select group of players who really hope to never have their names called during the game. They are members of the offensive line, and their job is to protect other players so they can deliver the ball to the goal to score points. When you do hear their name called, it is usually because they made a mistake and the player that they were supposed to protect ended up flat on his back admiring the clouds in the sky instead of advancing towards the goal to scoring point. Even on the rare occasion their name is called for a good reason, it is usually because they were making up for a teammate who had made a mistake and they covered up for them. The role of offensive lineman is a very good analogy for the role of the admin DBA. As a DBA, you are called on to be barely visible and rarely heard, protecting the company data assets tenaciously, even though the enemies to our craft surround us on all sides:. Developers: Cries of ‘foul!’ often ensue when the DBA says that they want data integrity to be stringently enforced and that documentation is needed so they can support systems, mostly because every error occurrence in the enterprise will be initially blamed on the database and fall to the DBA to troubleshoot. Insisting too loudly may bring those cries of ‘foul’ that somewhat remind you of when your 2 year old daughter didn't want to go to bed. The result of this petulance is that the next "enemy" gets involved. Managers: The concerns that motivate DBAs to argue will not excite the kind of manager who gets his technical knowledge from a glossy magazine filled with buzzwords, charts, and pretty pictures. However, the other programmers in the organization will tickle the buzzword void with a stream of new-sounding ideas and technologies constantly, along with warnings that if we did care about data integrity and document things, the budget would explode! In contrast, the arguments for integrity of data and supportability tend to be about as exciting as watching grass grow, and far too many manager types seem to prefer to smoke it than watch it. Packaged Applications: The DBA is rarely given a chance to review a new application that is being demonstrated for the enterprise, and rarer still is the DBA that gets a veto of an application because the database it uses has clearly been created by an architect that won't read a data modeling book because he is already married. More often than not this leads to hours of work for the DBA trying to performance-tune a database with a menagerie of rules that must be followed to stay within the  application support agreement, such as no changing indexes on a third party schema even though there are 10 billion rows instead of the 10 thousand when the system was last optimized. Hardware Failures: Physical disks, networking devices, memory, and backup devices all come with a measure known as ‘mean time before failure’ and it is never listed in centuries or eons. More like years, and the term ‘mean’ indicates that half of the devices are expected to fail before that, which by my calendar means any hour of any day that it wants to fail it will. But the DBA sucks it up and does the task at hand with a humility that makes them nearly invisible to all but the most observant person in the organization. The best DBAs I know are so proactive in their relentless pursuit of perfection that they detect many of the bugs (which they seldom caused) in the system well before they become a problem. In the end the DBA gets noticed for one of same two reasons as the offensive lineman. You make a mistake, like dropping a critical production database that had never been backed up; or when a system crashes for any reason whatsoever and they are on the spot with troubleshooting and system restoration plans that have been well thought out, tested, and tested again. Not because there is any glory in it, but because it is what they do.   Note: The characteristics of the professions referred to in this blog are meant to be overstated stereotypes for humorous effect, and even some DBAs aren't quite this perfect. If you are reading this far and haven’t hand written a 10 page flaming comment about how you are a _______ and you aren’t like this, that is awesome. Not every situation applies to everyone, but if you have never worked with a bad packaged app, a magazine trained manager, programmers that aren’t team players, or hardware that occasionally failed, relax and go have a unicorn sandwich before you wake up.

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• "Imprinting" as a language feature?

  - by MKO

  Idea I had this idea for a language feature that I think would be useful, does anyone know of a language that implements something like this? The idea is that besides inheritance a class can also use something called "imprinting" (for lack of better term). A class can imprint one or several (non-abstract) classes. When a class imprints another class it gets all it's properties and all it's methods. It's like the class storing an instance of the imprinted class and redirecting it's methods/properties to it. A class that imprints another class therefore by definition also implements all it's interfaces and it's abstract class. So what's the point? Well, inheritance and polymorphism is hard to get right. Often composition gives far more flexibility. Multiple inheritance offers a slew of different problems without much benefits (IMO). I often write adapter classes (in C#) by implementing some interface and passing along the actual methods/properties to an encapsulated object. The downside to that approach is that if the interface changes the class breaks. You also you have to put in a lot of code that does nothing but pass things along to the encapsulated object. A classic example is that you have some class that implements IEnumerable or IList and contains an internal class it uses. With this technique things would be much easier Example (c#) [imprint List<Person> as peopleList] public class People : PersonBase { public void SomeMethod() { DoSomething(this.Count); //Count is from List } } //Now People can be treated as an List<Person> People people = new People(); foreach(Person person in people) { ... } peopleList is an alias/variablename (of your choice)used internally to alias the instance but can be skipped if not needed. One thing that's useful is to override an imprinted method, that could be achieved with the ordinary override syntax public override void Add(Person person) { DoSomething(); personList.Add(person); } note that the above is functional equivalent (and could be rewritten by the compiler) to: public class People : PersonBase , IList<Person> { private List<Person> personList = new List<Person>(); public override void Add(object obj) { this.personList.Add(obj) } public override int IndexOf(object obj) { return personList.IndexOf(obj) } //etc etc for each signature in the interface } only if IList changes your class will break. IList won't change but an interface that you, someone in your team, or a thirdparty has designed might just change. Also this saves you writing a whole lot of code for some interfaces/abstract classes. Caveats There's a couple of gotchas. First we, syntax must be added to call the imprinted classes's constructors from the imprinting class constructor. Also, what happends if a class imprints two classes which have the same method? In that case the compiler would detect it and force the class to define an override of that method (where you could chose if you wanted to call either imprinted class or both) So what do you think, would it be useful, any caveats? It seems it would be pretty straightforward to implement something like that in the C# language but I might be missing something :) Sidenote - Why is this different from multiple inheritance Ok, so some people have asked about this. Why is this different from multiple inheritance and why not multiple inheritance. In C# methods are either virtual or not. Say that we have ClassB who inherits from ClassA. ClassA has the methods MethodA and MethodB. ClassB overrides MethodA but not MethodB. Now say that MethodB has a call to MethodA. if MethodA is virtual it will call the implementation that ClassB has, if not it will use the base class, ClassA's MethodA and you'll end up wondering why your class doesn't work as it should. By the terminology sofar you might already confused. So what happens if ClassB inherits both from ClassA and another ClassC. I bet both programmers and compilers will be scratching their heads. The benefit of this approach IMO is that the imprinting classes are totally encapsulated and need not be designed with multiple inheritance in mind. You can basically imprint anything.

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• VS2010 crashes when opening a vsp generated using VS 2012

  - by Tarun Arora

  I recently profiled some web applications using Visual Studio 2012, a vsp (Visual Studio Profile) file was generated as a result of the profiling session. I could successfully open the vsp file in Visual Studio 2012 as expected but when I tried to open the vsp file in Visual Studio 2010 the VS2010 IDE crashed. As a responsible citizen I raised bug # 762202 on Microsoft Connect site using the Microsoft Visual Studio 2012 Feedback Client. Note – In case you didn’t already know, VSP generated in Visual Studio 2012 is not backward compatible. Please refer below for the steps to reproduce the issue and the resolution of the connect bug. 1. Behaviour and Steps to Reproduce the Issue Description I have generated a vsp file by using the Visual Studio 2012 Standalone profiler. When I try and open the vsp file in Visual Studio 2010 the IDE crashes. I understand that a vsp generated by using VS 2012 cannot be opened in VS 2010, but the IDE crashing is not the behaviour I would expect to see. Steps to Reproduce the Issue 1. Pick up the Stand lone profiler from the VS 2012 installation media. The folder has both x 64 and x86 installer, since the machine I am using is x64 bit. I have installed the x64 version of the standalone profiler. 2. I have configured the system path by setting the 'environment variable' path to where the profiler is installed. In my case this is, C:\Program Files (x86)\Microsoft Visual Studio 11.0\Team Tools\Performance Tools 3. Created a new environment variable _NT_SYMBOL_PATH and set its value to CACHE*C:\SYMBOLSCACHE;SRV*C:\SYMBOLSCACHE*HTTP://MSDL.MICROSOFT.COM/DOWNLOAD/SYMBOLS;\\FOO\BUILD1234 4. Open up CMD as an administrator and run 'VSPerfASPNETCmd /tip http://localhost:56180/ /o:C:\Temp\SampleEISK.vsp' 5. This generates the following message on the cmd       Microsoft (R) VSPerf ASP.NET Command, Version 11.0.0.0     Copyright (C) Microsoft Corporation. All rights reserved.     Configuring and attaching to ASP.NET process. Please wait.     Setting up profiling environment.     Starting monitor.     Launching ASP.NET service.     Attaching Monitor to process.     Launching Internet Explorer.     The profiler is attached to ASP.net. Please run your application scenario now.     Press Enter to stop data collection...   6. I perform certain actions and then I come back to the cmd and hit enter to shut down the profiling. Once I do this, the following message is written to the cmd, Press Enter to stop data collection... Profiling now shut down. Report file "C:\Temp\SampleEISK.vsp" was generated. Running VsPerfReport, packing symbols into the .VSP. Shutting down profiling and restarting ASP.NET. Please wait. Restarting w3wp.exe.   7. I look in the C:\Temp folder and I can see the SampleEISK.vsp file generated. I can successfully open this file in Visual Studio 2012. 8. When I am trying to open the vsp file in VS 2010 the VS 2010 IDE crashes. Kaboooom! What I would expect to happen I expect to receive a message "VS 2010 does not support the vsp file generated by VS 2012". What actually happened The VS 2010 IDE crashed 2. Resolution This is a valid bug! However, there isn’t much value in releasing a hotfix for this issue. Refer below to the resolution provided by the Visual Studio Profiler Team.  Thank you for taking the time to report this issue. We completely agree that Visual Studio 2010 should not crash. However in this particular case this is not a bug we are going to retroactively release a fix to 2010 for at this point. Given that a fix would not unblock the scenario of opening a 2012 created file on Visual Studio 2010, and there is not an active update channel for Visual Studio 2010 other than manually locating and installing hot fixes, we will not be fixing this particular issue. Best Regards, Visual Studio Profiler Team   Though it would be great to improve the behaviour however, this is not a defect that would stop you from progressing in any way. It’s important to note however that VSP files generated by Visual Studio 2012 are not backward compatible so you should refrain from opening these files in Visual Studio 2010.

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• High Availability for IaaS, PaaS and SaaS in the Cloud

  - by BuckWoody

  Outages, natural disasters and unforeseen events have proved that even in a distributed architecture, you need to plan for High Availability (HA). In this entry I'll explain a few considerations for HA within Infrastructure-as-a-Service (IaaS), Platform-as-a-Service (PaaS) and Software-as-a-Service (SaaS). In a separate post I'll talk more about Disaster Recovery (DR), since each paradigm has a different way to handle that. Planning for HA in IaaS IaaS involves Virtual Machines - so in effect, an HA strategy here takes on many of the same characteristics as it would on-premises. The primary difference is that the vendor controls the hardware, so you need to verify what they do for things like local redundancy and so on from the hardware perspective. As far as what you can control and plan for, the primary factors fall into three areas: multiple instances, geographical dispersion and task-switching. In almost every cloud vendor I've studied, to ensure your application will be protected by any level of HA, you need to have at least two of the Instances (VM's) running. This makes sense, but you might assume that the vendor just takes care of that for you - they don't. If a single VM goes down (for whatever reason) then the access to it is lost. Depending on multiple factors, you might be able to recover the data, but you should assume that you can't. You should keep a sync to another location (perhaps the vendor's storage system in another geographic datacenter or to a local location) to ensure you can continue to serve your clients. You'll also need to host the same VM's in another geographical location. Everything from a vendor outage to a network path problem could prevent your users from reaching the system, so you need to have multiple locations to handle this. This means that you'll have to figure out how to manage state between the geo's. If the system goes down in the middle of a transaction, you need to figure out what part of the process the system was in, and then re-create or transfer that state to the second set of systems. If you didn't write the software yourself, this is non-trivial. You'll also need a manual or automatic process to detect the failure and re-route the traffic to your secondary location. You could flip a DNS entry (if your application can tolerate that) or invoke another process to alias the first system to the second, such as load-balancing and so on. There are many options, but all of them involve coding the state into the application layer. If you've simply moved a state-ful application to VM's, you may not be able to easily implement an HA solution. Planning for HA in PaaS Implementing HA in PaaS is a bit simpler, since it's built on the concept of stateless applications deployment. Once again, you need at least two copies of each element in the solution (web roles, worker roles, etc.) to remain available in a single datacenter. Also, you need to deploy the application again in a separate geo, but the advantage here is that you could work out a "shared storage" model such that state is auto-balanced across the world. In fact, you don't have to maintain a "DR" site, the alternate location can be live and serving clients, and only take on extra load if the other site is not available. In Windows Azure, you can use the Traffic Manager service top route the requests as a type of auto balancer. Even with these benefits, I recommend a second backup of storage in another geographic location. Storage is inexpensive; and that second copy can be used for not only HA but DR. Planning for HA in SaaS In Software-as-a-Service (such as Office 365, or Hadoop in Windows Azure) You have far less control over the HA solution, although you still maintain the responsibility to ensure you have it. Since each SaaS is different, check with the vendor on the solution for HA - and make sure you understand what they do and what you are responsible for. They may have no HA for that solution, or pin it to a particular geo, or perhaps they have a massive HA built in with automatic load balancing (which is often the case).   All of these options (with the exception of SaaS) involve higher costs for the design. Do not sacrifice reliability for cost - that will always cost you more in the end. Build in the redundancy and HA at the very outset of the project - if you try to tack it on later in the process the business will push back and potentially not implement HA. References: http://www.bing.com/search?q=windows+azure+High+Availability  (each type of implementation is different, so I'm routing you to a search on the topic - look for the "Patterns and Practices" results for the area in Azure you're interested in)

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• Triangle Picking Picking Back faces

  - by Tangeleno

  I'm having a bit of trouble with 3D picking, at first I thought my ray was inaccurate but it turns out that the picking is happening on faces facing the camera and faces facing away from the camera which I'm currently culling. Here's my ray creation code, I'm pretty sure the problem isn't here but I've been wrong before. private uint Pick() { Ray cursorRay = CalculateCursorRay(); Vector3? point = Control.Mesh.RayCast(cursorRay); if (point != null) { Tile hitTile = Control.TileMesh.GetTileAtPoint(point); return hitTile == null ? uint.MaxValue : (uint)(hitTile.X + hitTile.Y * Control.Generator.TilesWide); } return uint.MaxValue; } private Ray CalculateCursorRay() { Vector3 nearPoint = Control.Camera.Unproject(new Vector3(Cursor.Position.X, Control.ClientRectangle.Height - Cursor.Position.Y, 0f)); Vector3 farPoint = Control.Camera.Unproject(new Vector3(Cursor.Position.X, Control.ClientRectangle.Height - Cursor.Position.Y, 1f)); Vector3 direction = farPoint - nearPoint; direction.Normalize(); return new Ray(nearPoint, direction); } public Vector3 Camera.Unproject(Vector3 source) { Vector4 result; result.X = (source.X - _control.ClientRectangle.X) * 2 / _control.ClientRectangle.Width - 1; result.Y = (source.Y - _control.ClientRectangle.Y) * 2 / _control.ClientRectangle.Height - 1; result.Z = source.Z - 1; if (_farPlane - 1 == 0) result.Z = 0; else result.Z = result.Z / (_farPlane - 1); result.W = 1f; result = Vector4.Transform(result, Matrix4.Invert(ProjectionMatrix)); result = Vector4.Transform(result, Matrix4.Invert(ViewMatrix)); result = Vector4.Transform(result, Matrix4.Invert(_world)); result = Vector4.Divide(result, result.W); return new Vector3(result.X, result.Y, result.Z); } And my triangle intersection code. Ripped mainly from the XNA picking sample. public float? Intersects(Ray ray) { float? closestHit = Bounds.Intersects(ray); if (closestHit != null && Vertices.Length == 3) { Vector3 e1, e2; Vector3.Subtract(ref Vertices[1].Position, ref Vertices[0].Position, out e1); Vector3.Subtract(ref Vertices[2].Position, ref Vertices[0].Position, out e2); Vector3 directionCrossEdge2; Vector3.Cross(ref ray.Direction, ref e2, out directionCrossEdge2); float determinant; Vector3.Dot(ref e1, ref directionCrossEdge2, out determinant); if (determinant > -float.Epsilon && determinant < float.Epsilon) return null; float inverseDeterminant = 1.0f/determinant; Vector3 distanceVector; Vector3.Subtract(ref ray.Position, ref Vertices[0].Position, out distanceVector); float triangleU; Vector3.Dot(ref distanceVector, ref directionCrossEdge2, out triangleU); triangleU *= inverseDeterminant; if (triangleU < 0 || triangleU > 1) return null; Vector3 distanceCrossEdge1; Vector3.Cross(ref distanceVector, ref e1, out distanceCrossEdge1); float triangleV; Vector3.Dot(ref ray.Direction, ref distanceCrossEdge1, out triangleV); triangleV *= inverseDeterminant; if (triangleV < 0 || triangleU + triangleV > 1) return null; float rayDistance; Vector3.Dot(ref e2, ref distanceCrossEdge1, out rayDistance); rayDistance *= inverseDeterminant; if (rayDistance < 0) return null; return rayDistance; } return closestHit; } I'll admit I don't fully understand all of the math behind the intersection and that is something I'm working on, but my understanding was that if rayDistance was less than 0 the face was facing away from the camera, and shouldn't be counted as a hit. So my question is, is there an issue with my intersection or ray creation code, or is there another check I need to perform to tell if the face is facing away from the camera, and if so any hints on what that check might contain would be appreciated.

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• Pirates, Treasure Chests and Architectural Mapping

  Pirate 1: Why do pirates create treasure maps? Pirate 2: I do not know.Pirate 1: So they can find their gold. Yes, that was a bad joke, but it does illustrate a point. Pirates are known for drawing treasure maps to their most prized possession. These documents detail the decisions pirates made in order to hide and find their chests of gold. The map allows them to trace the steps they took originally to hide their treasure so that they may return. As software engineers, programmers, and architects we need to treat software implementations much like our treasure chest. Why is software like a treasure chest? It cost money, time,  and resources to develop (Usually) It can make or save money, time, and resources (Hopefully) If we operate under the assumption that software is like a treasure chest then wouldn’t make sense to document the steps, rationale, concerns, and decisions about how it was designed? Pirates are notorious for documenting where they hide their treasure.  Shouldn’t we as creators of software do the same? By documenting our design decisions and rationale behind them will help others be able to understand and maintain implemented systems. This can only be done if the design decisions are correctly mapped to its corresponding implementation. This allows for architectural decisions to be traced from the conceptual model, architectural design and finally to the implementation. Mapping gives software professional a method to trace the reason why specific areas of code were developed verses other options. Just like the pirates we need to able to trace our steps from the start of a project to its implementation,  so that we will understand why specific choices were chosen. The traceability of a software implementation that actually maps back to its originating design decisions is invaluable for ensuring that architectural drifting and erosion does not take place. The drifting and erosion is prevented by allowing others to understand the rational of why an implementation was created in a specific manor or methodology The process of mapping distinct design concerns/decisions to the location of its implemented is called traceability. In this context traceability is defined as method for connecting distinctive software artifacts. This process allows architectural design models and decisions to be directly connected with its physical implementation. The process of mapping architectural design concerns to a software implementation can be very complex. However, most design decision can be placed in  a few generalized categories. Commonly Mapped Design Decisions Design Rationale Components and Connectors Interfaces Behaviors/Properties Design rational is one of the hardest categories to map directly to an implementation. Typically this rational is mapped or document in code via comments. These comments consist of general design decisions and reasoning because they do not directly refer to a specific part of an application. They typically focus more on the higher level concerns. Components and connectors can directly be mapped to architectural concerns. Typically concerns subdivide an application in to distinct functional areas. These functional areas then can map directly back to their originating concerns.Interfaces can be mapped back to design concerns in one of two ways. Interfaces that pertain to specific function definitions can be directly mapped back to its originating concern(s). However, more complicated interfaces require additional analysis to ensure that the proper mappings are created. Depending on the complexity some Behaviors\Properties can be translated directly into a generic implementation structure that is ready for business logic. In addition, some behaviors can be translated directly in to an actual implementation depending on the complexity and architectural tools used. Mapping design concerns to an implementation is a lot of work to maintain, but is doable. In order to ensure that concerns are mapped correctly and that an implementation correctly reflects its design concerns then one of two standard approaches are usually used. All Changes Come From ArchitectureBy forcing all application changes to come through the architectural model prior to implementation then the existing mappings will be used to locate where in the implementation changes need to occur. Allow Changes From Implementation Or Architecture By allowing changes to come from the implementation and/or the architecture then the other area must be kept in sync. This methodology is more complex compared to the previous approach.  One reason to justify the added complexity for an application is due to the fact that this approach tends to detect and prevent architectural drift and erosion. Additionally, this approach is usually maintained via software because of the complexity. Reference:Taylor, R. N., Medvidovic, N., & Dashofy, E. M. (2009). Software architecture: Foundations, theory, and practice Hoboken, NJ: John Wiley & Sons  

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• Fixing a collision detection bug in Slick2D

  - by Jesse Prescott

  My game has a bug with collision detection. If you go against the wall and tap forward/back sometimes the game thinks the speed you travelled at is 0 and the game doesn't know how to get you out of the wall. My collision detection works by getting the speed you hit the wall at and if it is positive it moves you back, if it is negative it moves you forward. It might help if you download it: https://rapidshare.com/files/1550046269/game.zip Sorry if I explained badly, it's hard to explain. float maxSpeed = 0.3f; float minSpeed = -0.2f; float acceleration = 0.002f; float deacceleration = 0.001f; float slowdownSpeed = 0.002f; float rotateSpeed = 0.08f; static float currentSpeed = 0; boolean up = false; boolean down = false; boolean noKey = false; static float rotate = 0; //Image effect system static String locationCarNormal; static String locationCarFront; static String locationCarBack; static String locationCarBoth; static boolean carFront = false; static boolean carBack = false; static String imageRef; boolean collision = false; public ComponentPlayerMovement(String id, String ScarNormal, String ScarFront, String ScarBack, String ScarBoth) { this.id = id; playerBody = new Rectangle(900/2-16, 700/2-16, 32, 32); locationCarNormal = ScarNormal; locationCarFront = ScarFront; locationCarBack = ScarBack; locationCarBoth = ScarBoth; imageRef = locationCarNormal; } @Override public void update(GameContainer gc, StateBasedGame sbg, int delta) throws SlickException { Input input = gc.getInput(); playerBody.transform(Transform.createRotateTransform(2)); float hip = currentSpeed * delta; float unstuckspeed = 0.05f * delta; if(carBack && !carFront) { imageRef = locationCarBack; ComponentImageRender.updateImage(); } else if(carFront && !carBack) { imageRef = locationCarFront; ComponentImageRender.updateImage(); } else if(carFront && carBack) { imageRef = locationCarBoth; ComponentImageRender.updateImage(); } if(input.isKeyDown(Input.KEY_RIGHT)) { rotate += rotateSpeed * delta; owner.setRotation(rotate); } if(input.isKeyDown(Input.KEY_LEFT)) { rotate -= rotateSpeed * delta; owner.setRotation(rotate); } if(input.isKeyDown(Input.KEY_UP)) { if(!collision) { up = true; noKey = false; if(currentSpeed < maxSpeed) { currentSpeed += acceleration; } MapCoordStorage.mapX += hip * Math.sin(Math.toRadians(rotate)); MapCoordStorage.mapY -= hip * Math.cos(Math.toRadians(rotate)); } else { currentSpeed = 1; } } else if(input.isKeyDown(Input.KEY_DOWN) && !collision) { down = true; noKey = false; if(currentSpeed > minSpeed) { currentSpeed -= slowdownSpeed; } MapCoordStorage.mapX += hip * Math.sin(Math.toRadians(rotate)); MapCoordStorage.mapY -= hip * Math.cos(Math.toRadians(rotate)); } else { noKey = true; if(currentSpeed > 0) { currentSpeed -= deacceleration; } else if(currentSpeed < 0) { currentSpeed += acceleration; } MapCoordStorage.mapX += hip * Math.sin(Math.toRadians(rotate)); MapCoordStorage.mapY -= hip * Math.cos(Math.toRadians(rotate)); } if(entityCollisionWith()) { collision = true; if(currentSpeed > 0 || up) { up = true; currentSpeed = 0; carFront = true; MapCoordStorage.mapX += unstuckspeed * Math.sin(Math.toRadians(rotate-180)); MapCoordStorage.mapY -= unstuckspeed * Math.cos(Math.toRadians(rotate-180)); } else if(currentSpeed < 0 || down) { down = true; currentSpeed = 0; carBack = true; MapCoordStorage.mapX += unstuckspeed * Math.sin(Math.toRadians(rotate)); MapCoordStorage.mapY -= unstuckspeed * Math.cos(Math.toRadians(rotate)); } else { currentSpeed = 0; } } else { collision = false; up = false; down = false; } if(currentSpeed >= -0.01f && currentSpeed <= 0.01f && noKey && !collision) { currentSpeed = 0; } } public static boolean entityCollisionWith() throws SlickException { for (int i = 0; i < BlockMap.entities.size(); i++) { Block entity1 = (Block) BlockMap.entities.get(i); if (playerBody.intersects(entity1.poly)) { return true; } } return false; } }

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• Understanding implementation of glu.PickMatrix()

  - by stoney78us

  I am working on an OpenGL project which requires object selection feature. I use OpenTK framework to do this; however OpenTK doesn't support glu.PickMatrix() method to define the picking region. I ended up googling its implementation and here is what i got: void GluPickMatrix(double x, double y, double deltax, double deltay, int[] viewport) { if (deltax <= 0 || deltay <= 0) { return; } GL.Translate((viewport[2] - 2 * (x - viewport[0])) / deltax, (viewport[3] - 2 * (y - viewport[1])) / deltay, 0); GL.Scale(viewport[2] / deltax, viewport[3] / deltay, 1.0); } I totally fail to understand this piece of code. Moreover, this doesn't work with my following code sample: //selectbuffer private int[] _selectBuffer = new int[512]; private void Init() { float[] triangleVertices = new float[] { 0.0f, 1.0f, 0.0f, -1.0f, -1.0f, 0.0f, 1.0f, -1.0f, 0.0f }; float[] _triangleColors = new float[] { 0.0f, 1.0f, 0.0f, 1.0f, 0.0f, 0.0f, 0.0f, 0.0f, 1.0f }; GL.GenBuffers(2, _vBO); GL.BindBuffer(BufferTarget.ArrayBuffer, _vBO[0]); GL.BufferData(BufferTarget.ArrayBuffer, new IntPtr(sizeof(float) * _triangleVertices.Length), _triangleVertices, BufferUsageHint.StaticDraw); GL.VertexPointer(3, VertexPointerType.Float, 0, 0); GL.BindBuffer(BufferTarget.ArrayBuffer, _vBO[1]); GL.BufferData(BufferTarget.ArrayBuffer, new IntPtr(sizeof(float) * _triangleColors.Length), _triangleColors, BufferUsageHint.StaticDraw); GL.ColorPointer(3, ColorPointerType.Float, 0, 0); GL.EnableClientState(ArrayCap.VertexArray); GL.EnableClientState(ArrayCap.ColorArray); //Selectbuffer set up GL.SelectBuffer(512, _selectBuffer); } private void glControlWindow_Paint(object sender, PaintEventArgs e) { GL.Clear(ClearBufferMask.ColorBufferBit); GL.Clear(ClearBufferMask.DepthBufferBit); float[] eyes = { 0.0f, 0.0f, -10.0f }; float[] target = { 0.0f, 0.0f, 0.0f }; Matrix4 projection = Matrix4.CreatePerspectiveFieldOfView(0.785398163f, 4.0f / 3.0f, 0.1f, 100f); //45 degree = 0.785398163 rads Matrix4 view = Matrix4.LookAt(eyes[0], eyes[1], eyes[2], target[0], target[1], target[2], 0, 1, 0); Matrix4 model = Matrix4.Identity; Matrix4 MV = view * model; //First Clear Buffers GL.Clear(ClearBufferMask.ColorBufferBit); GL.Clear(ClearBufferMask.DepthBufferBit); GL.MatrixMode(MatrixMode.Projection); GL.LoadIdentity(); GL.LoadMatrix(ref projection); GL.MatrixMode(MatrixMode.Modelview); GL.LoadIdentity(); GL.LoadMatrix(ref MV); GL.Viewport(0, 0, glControlWindow.Width, glControlWindow.Height); GL.Enable(EnableCap.DepthTest); //Enable correct Z Drawings GL.DepthFunc(DepthFunction.Less); //Enable correct Z Drawings GL.MatrixMode(MatrixMode.Modelview); GL.PushMatrix(); GL.Translate(3.0f, 0.0f, 0.0f); DrawTriangle(); GL.PopMatrix(); GL.PushMatrix(); GL.Translate(-3.0f, 0.0f, 0.0f); DrawTriangle(); GL.PopMatrix(); //Finally... GraphicsContext.CurrentContext.VSync = true; //Caps frame rate as to not over run GPU glControlWindow.SwapBuffers(); //Takes from the 'GL' and puts into control } private void DrawTriangle() { GL.BindBuffer(BufferTarget.ArrayBuffer, _vBO[0]); GL.VertexPointer(3, VertexPointerType.Float, 0, 0); GL.EnableClientState(ArrayCap.VertexArray); GL.DrawArrays(BeginMode.Triangles, 0, 3); GL.DisableClientState(ArrayCap.VertexArray); } //mouse click event implementation private void glControlWindow_MouseClick(object sender, System.Windows.Forms.MouseEventArgs e) { //Enter Select mode. Pretend drawing. GL.RenderMode(RenderingMode.Select); int[] viewport = new int[4]; GL.GetInteger(GetPName.Viewport, viewport); GL.PushMatrix(); GL.MatrixMode(MatrixMode.Projection); GL.LoadIdentity(); GluPickMatrix(e.X, e.Y, 5, 5, viewport); Matrix4 projection = Matrix4.CreatePerspectiveFieldOfView(0.785398163f, 4.0f / 3.0f, 0.1f, 100f); // this projection matrix is the same as one in glControlWindow_Paint method. GL.LoadMatrix(ref projection); GL.MatrixMode(MatrixMode.Modelview); int i = 0; int hits; GL.PushMatrix(); GL.Translate(3.0f, 0.0f, 0.0f); GL.PushName(i); DrawTriangle(); GL.PopName(); GL.PopMatrix(); i++; GL.PushMatrix(); GL.Translate(-3.0f, 0.0f, 0.0f); GL.PushName(i); DrawTriangle(); GL.PopName(); GL.PopMatrix(); hits = GL.RenderMode(RenderingMode.Render); .....hits processing code goes here... GL.PopMatrix(); glControlWindow.Invalidate(); } I expect to get only one hit everytime i click inside a triangle, but i always get 2 no matter where i click. I suspect there is something wrong with the implementation of the GluPickMatrix, I haven't figured out yet.

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• Determining the angle to fire a shot when target and shooter moves, and bullet moves with shooter velocity added in

  - by Azaral

  I saw this question: Predicting enemy position in order to have an object lead its target and followed the link in the answer to stack overflow. In the stack overflow page I used the 2nd answer, the one that is a large mathematical derivation. My situation is a little different though. My first question though is will the answer provided in the stack overflow page even work to begin with, assuming the original circumstances of moving target and stationary shooter. My situation is a little different than that situation. My target moves, the shooter moves, and the bullets from the shooter start off with the velocities in x and y added to the bullets' x and y velocities. If you are sliding to the right, the bullets will remain in front of you as you move so as long as your velocity remains constant. What I'm trying to do is to get the enemy to be able to determine where they need to shoot in order to hit the player. Unless the player and enemy is stationary, the velocity from the ship adding to the velocity of the bullets will cause a miss. I'd rather like to prevent that. I used the formula in the stack overflow answer and did what I thought were the appropriate adjustments. I've been banging at this for the last four hours and I just can't make it click. It is probably something really simple and boneheaded that I am missing (that seems to be a lot of my problems lately). Here is the solution presented from the stack overflow answer: It boils down to solving a quadratic equation of the form: a * sqr(x) + b * x + c == 0 Note that by sqr I mean square, as opposed to square root. Use the following values: a := sqr(target.velocityX) + sqr(target.velocityY) - sqr(projectile_speed) b := 2 * (target.velocityX * (target.startX - cannon.X) + target.velocityY * (target.startY - cannon.Y)) c := sqr(target.startX - cannon.X) + sqr(target.startY - cannon.Y) Now we can look at the discriminant to determine if we have a possible solution. disc := sqr(b) - 4 * a * c If the discriminant is less than 0, forget about hitting your target -- your projectile can never get there in time. Otherwise, look at two candidate solutions: t1 := (-b + sqrt(disc)) / (2 * a) t2 := (-b - sqrt(disc)) / (2 * a) Note that if disc == 0 then t1 and t2 are equal. If there are no other considerations such as intervening obstacles, simply choose the smaller positive value. (Negative t values would require firing backward in time to use!) Substitute the chosen t value back into the target's position equations to get the coordinates of the leading point you should be aiming at: aim.X := t * target.velocityX + target.startX aim.Y := t * target.velocityY + target.startY Here is my code, after being corrected by Sam Hocevar (thank you again for your help!). It still doesn't work. For some reason it never enters the section of code inside the if(disc = 0) (obviously because it is always less than zero but...). However, if I plug the numbers from my game log on the enemy and player positions and velocities it outputs a valid firing solution. I have looked at the code side by side a couple of times now and I can't find any differences. There has got to be something simple I'm missing here. If someone else could look at this code and determine what is going on here I'd appreciate it. I know it's not going through that section because if it were, shouldShoot would become true and the enemy would be blasting away at the player. This section calls the function in question, CalculateShootHeading() if(shouldMove) { UseEngines(); } x += xVelocity; y += yVelocity; CalculateShootHeading(); if(shouldShoot) { ShootWeapons(); } UpdateWeapons(); This is CalculateShootHeading(). This is inside the enemy class so x and y are the enemy's x and y and the same with velocity. One output from my game log gives Player X = 2108, Player Y = -180.956, Player X velocity = 10.9949, Player Y Velocity = -6.26017, Enemy X = 1988.31, Enemy Y = -339.051, Enemy X velocity = 1.81666, Enemy Y velocity = -9.67762, 0 enemy projectiles. The output from the console tester is Bullet position = 2210.49, -239.313 and Player Position = 2210.49, -239.313. This doesn't make any sense. The only thing that could be different is the code or the input into my function in the game and I've checked that and I don't think that it is wrong as it's updated before this and never changed. float const bulletSpeed = 30.f; float const dx = playerX - x; float const dy = playerY - y; float const vx = playerXVelocity - xVelocity; float const vy = playerYVelocity - yVelocity; float const a = vx * vx + vy * vy - bulletSpeed * bulletSpeed; float const b = 2.f * (vx * dx + vy * dy); float const c = dx * dx + dy * dy; float const disc = b * b - 4.f * a * c; shouldShoot = false; if (disc >= 0.f) { float t0 = (-b - std::sqrt(disc)) / (2.f * a); float t1 = (-b + std::sqrt(disc)) / (2.f * a); if (t0 < 0.f || (t1 < t0 && t1 >= 0.f)) { t0 = t1; } if (t0 >= 0.f) { float shootx = vx + dx / t0; float shooty = vy + dy / t0; heading = std::atan2(shooty, shootx) * RAD2DEGREE; } shouldShoot = true; }

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• Enemies don't shoot. What is wrong? [closed]

  - by Bryan

  I want that every enemy shoots independently bullets. If an enemy’s bullet left the screen, the enemy can shoot a new bullet. Not earlier. But for the moment, the enemies don't shoot. Not a single bullet. I guess their is something wrong with my Enemy class, but I can't find a bug and I get no error message. What is wrong? public class Map { Texture2D myEnemy, myBullet ; Player Player; List<Enemy> enemieslist = new List<Enemy>(); List<Bullet> bulletslist = new List<Bullet>(); float fNextEnemy = 0.0f; float fEnemyFreq = 3.0f; int fMaxEnemy = 3 ; Vector2 Startposition = new Vector2(200, 200); GraphicsDeviceManager graphicsDevice; public Map(GraphicsDeviceManager device) { graphicsDevice = device; } public void Load(ContentManager content) { myEnemy = content.Load<Texture2D>("enemy"); myBullet = content.Load<Texture2D>("bullet"); Player = new Player(graphicsDevice); Player.Load(content); } public void Update(GameTime gameTime) { Player.Update(gameTime); float delta = (float)gameTime.ElapsedGameTime.TotalSeconds; for(int i = enemieslist.Count - 1; i >= 0; i--) { // Update Enemy Enemy enemy = enemieslist[i]; enemy.Update(gameTime, this.graphicsDevice, Player.playershape.Position, delta); // Try to remove an enemy if (enemy.Remove == true) { enemieslist.Remove(enemy); enemy.Remove = false; } } this.fNextEnemy += delta; //New enemy if (fMaxEnemy > 0) { if ((this.fNextEnemy >= fEnemyFreq) && (enemieslist.Count < 3)) { Vector2 enemyDirection = Vector2.Normalize(Player.playershape.Position - Startposition) * 100f; enemieslist.Add(new Enemy(Startposition, enemyDirection, Player.playershape.Position)); fMaxEnemy -= 1; fNextEnemy -= fEnemyFreq; } } } public void Draw(SpriteBatch batch) { Player.Draw(batch); foreach (Enemy enemies in enemieslist) { enemies.Draw(batch, myEnemy); } foreach (Bullet bullets in bulletslist) { bullets.Draw(batch, myBullet); } } } public class Enemy { List<Bullet> bulletslist = new List<Bullet>(); private float nextShot = 0; private float shotFrequency = 2.0f; Vector2 vPos; Vector2 vMove; Vector2 vPlayer; public bool Remove; public bool Shot; public Enemy(Vector2 Pos, Vector2 Move, Vector2 Player) { this.vPos = Pos; this.vMove = Move; this.vPlayer = Player; this.Remove = false; this.Shot = false; } public void Update(GameTime gameTime, GraphicsDeviceManager graphics, Vector2 PlayerPos, float delta) { nextShot += delta; for (int i = bulletslist.Count - 1; i >= 0; i--) { // Update Bullet Bullet bullets = bulletslist[i]; bullets.Update(gameTime, graphics, delta); // Try to remove a bullet... Collision, hit, or outside screen. if (bullets.Remove == true) { bulletslist.Remove(bullets); bullets.Remove = false; } } if (nextShot >= shotFrequency) { this.Shot = true; nextShot -= shotFrequency; } // Does the enemy shot? if ((Shot == true) && (bulletslist.Count < 1)) // New bullet { Vector2 bulletDirection = Vector2.Normalize(PlayerPos - this.vPos) * 200f; bulletslist.Add(new Bullet(this.vPos, bulletDirection, PlayerPos)); Shot = false; } if (!Remove) { this.vMove = Vector2.Normalize(PlayerPos - this.vPos) * 100f; this.vPos += this.vMove * delta; if (this.vPos.X > graphics.PreferredBackBufferWidth + 1) { this.Remove = true; } else if (this.vPos.X < -20) { this.Remove = true; } if (this.vPos.Y > graphics.PreferredBackBufferHeight + 1) { this.Remove = true; } else if (this.vPos.Y < -20) { this.Remove = true; } } } public void Draw(SpriteBatch batch, Texture2D myTexture) { if (!Remove) { batch.Draw(myTexture, this.vPos, Color.White); } } } public class Bullet { Vector2 vPos; Vector2 vMove; Vector2 vPlayer; public bool Remove; public Bullet(Vector2 Pos, Vector2 Move, Vector2 Player) { this.Remove = false; this.vPos = Pos; this.vMove = Move; this.vPlayer = Player; } public void Update(GameTime gameTime, GraphicsDeviceManager graphics, float delta) { if (!Remove) { this.vPos += this.vMove * delta; if (this.vPos.X > graphics.PreferredBackBufferWidth +1) { this.Remove = true; } else if (this.vPos.X < -20) { this.Remove = true; } if (this.vPos.Y > graphics.PreferredBackBufferHeight +1) { this.Remove = true; } else if (this.vPos.Y < -20) { this.Remove = true; } } } public void Draw(SpriteBatch spriteBatch, Texture2D myTexture) { if (!Remove) { spriteBatch.Draw(myTexture, this.vPos, Color.White); } } }

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• Different fan behaviour in my laptop after upgrade, what to do now?

  - by student

  After upgrading from lubuntu 13.10 to 14.04 the fan of my laptop seems to run much more often than in 13.10. When it runs, it doesn't run continously but starts and stops every second. fwts fan results in Results generated by fwts: Version V14.03.01 (2014-03-27 02:14:17). Some of this work - Copyright (c) 1999 - 2014, Intel Corp. All rights reserved. Some of this work - Copyright (c) 2010 - 2014, Canonical. This test run on 12/05/14 at 21:40:13 on host Linux einstein 3.13.0-24-generic #47-Ubuntu SMP Fri May 2 23:30:00 UTC 2014 x86_64. Command: "fwts fan". Running tests: fan. fan: Simple fan tests. -------------------------------------------------------------------------------- Test 1 of 2: Test fan status. Test how many fans there are in the system. Check for the current status of the fan(s). PASSED: Test 1, Fan cooling_device0 of type Processor has max cooling state 10 and current cooling state 0. PASSED: Test 1, Fan cooling_device1 of type Processor has max cooling state 10 and current cooling state 0. PASSED: Test 1, Fan cooling_device2 of type LCD has max cooling state 15 and current cooling state 10. Test 2 of 2: Load system, check CPU fan status. Test how many fans there are in the system. Check for the current status of the fan(s). Loading CPUs for 20 seconds to try and get fan speeds to change. Fan cooling_device0 current state did not change from value 0 while CPUs were busy. Fan cooling_device1 current state did not change from value 0 while CPUs were busy. ADVICE: Did not detect any change in the CPU related thermal cooling device states. It could be that the devices are returning static information back to the driver and/or the fan speed is automatically being controlled by firmware using System Management Mode in which case the kernel interfaces being examined may not work anyway. ================================================================================ 3 passed, 0 failed, 0 warning, 0 aborted, 0 skipped, 0 info only. ================================================================================ 3 passed, 0 failed, 0 warning, 0 aborted, 0 skipped, 0 info only. Test Failure Summary ================================================================================ Critical failures: NONE High failures: NONE Medium failures: NONE Low failures: NONE Other failures: NONE Test |Pass |Fail |Abort|Warn |Skip |Info | ---------------+-----+-----+-----+-----+-----+-----+ fan | 3| | | | | | ---------------+-----+-----+-----+-----+-----+-----+ Total: | 3| 0| 0| 0| 0| 0| ---------------+-----+-----+-----+-----+-----+-----+ Here is the output of lsmod lsmod Module Size Used by i8k 14421 0 zram 18478 2 dm_crypt 23177 0 gpio_ich 13476 0 dell_wmi 12761 0 sparse_keymap 13948 1 dell_wmi snd_hda_codec_hdmi 46207 1 snd_hda_codec_idt 54645 1 rfcomm 69160 0 arc4 12608 2 dell_laptop 18168 0 bnep 19624 2 dcdbas 14928 1 dell_laptop bluetooth 395423 10 bnep,rfcomm iwldvm 232285 0 mac80211 626511 1 iwldvm snd_hda_intel 52355 3 snd_hda_codec 192906 3 snd_hda_codec_hdmi,snd_hda_codec_idt,snd_hda_intel snd_hwdep 13602 1 snd_hda_codec snd_pcm 102099 3 snd_hda_codec_hdmi,snd_hda_codec,snd_hda_intel snd_page_alloc 18710 2 snd_pcm,snd_hda_intel snd_seq_midi 13324 0 snd_seq_midi_event 14899 1 snd_seq_midi snd_rawmidi 30144 1 snd_seq_midi coretemp 13435 0 kvm_intel 143060 0 kvm 451511 1 kvm_intel snd_seq 61560 2 snd_seq_midi_event,snd_seq_midi joydev 17381 0 serio_raw 13462 0 iwlwifi 169932 1 iwldvm pcmcia 62299 0 snd_seq_device 14497 3 snd_seq,snd_rawmidi,snd_seq_midi snd_timer 29482 2 snd_pcm,snd_seq lpc_ich 21080 0 cfg80211 484040 3 iwlwifi,mac80211,iwldvm yenta_socket 41027 0 pcmcia_rsrc 18407 1 yenta_socket pcmcia_core 23592 3 pcmcia,pcmcia_rsrc,yenta_socket binfmt_misc 17468 1 snd 69238 17 snd_hwdep,snd_timer,snd_hda_codec_hdmi,snd_hda_codec_idt,snd_pcm,snd_seq,snd_rawmidi,snd_hda_codec,snd_hda_intel,snd_seq_device,snd_seq_midi soundcore 12680 1 snd parport_pc 32701 0 mac_hid 13205 0 ppdev 17671 0 lp 17759 0 parport 42348 3 lp,ppdev,parport_pc firewire_ohci 40409 0 psmouse 102222 0 sdhci_pci 23172 0 sdhci 43015 1 sdhci_pci firewire_core 68769 1 firewire_ohci crc_itu_t 12707 1 firewire_core ahci 25819 2 libahci 32168 1 ahci i915 783485 2 wmi 19177 1 dell_wmi i2c_algo_bit 13413 1 i915 drm_kms_helper 52758 1 i915 e1000e 254433 0 drm 302817 3 i915,drm_kms_helper ptp 18933 1 e1000e pps_core 19382 1 ptp video 19476 1 i915 I tried one answer to the similar question: loud fan on Ubuntu 14.04 and created a /etc/i8kmon.conf like the following: # Run as daemon, override with --daemon option set config(daemon) 1 # Automatic fan control, override with --auto option set config(auto) 1 # Status check timeout (seconds), override with --timeout option set config(timeout) 2 # Report status on stdout, override with --verbose option set config(verbose) 1 # Temperature thresholds: {fan_speeds low_ac high_ac low_batt high_batt} set config(0) {{0 0} -1 55 -1 55} set config(1) {{0 1} 50 60 55 65} set config(2) {{1 1} 55 80 60 85} set config(3) {{2 2} 70 128 75 128} With this setup the fan goes on even if the temperature is below 50 degree celsius (I don't see a pattern). However I get the impression that the CPU got's hotter in average than without this file. What changes from 13.10 to 14.04 may be responsible for this? If this is a bug, for which package I should report the bug?

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• BIP 11g Dynamic SQL

  - by Tim Dexter

  Back in the 10g release, if you wanted something beyond the standard query for your report extract; you needed to break out your favorite text editor. You gotta love 'vi' and hate emacs, am I right? And get to building a data template, they were/are lovely to write, such fun ... not! Its not fun writing them by hand but, you do get to do some cool stuff around the data extract including dynamic SQL. By that I mean the ability to add content dynamically to your your query at runtime. With 11g, we spoiled you with a visual builder, no more vi or notepad sessions, a friendly drag and drop interface allowing you to build hierarchical data sets, calculated columns, summary columns, etc. You can still create the dynamic SQL statements, its not so well documented right now, in lieu of doc updates here's the skinny. If you check out the 10g process to create dynamic sql in the docs. You need to create a data trigger function where you assign the dynamic sql to a global variable that's matched in your report SQL. In 11g, the process is really the same, BI Publisher just provides a bit more help to define what trigger code needs to be called. You still need to create the function and place it inside a package in the db. Here's a simple plsql package with the 'beforedata' function trigger. Spec create or replace PACKAGE BIREPORTS AS whereCols varchar2(2000); FUNCTION beforeReportTrig return boolean; end BIREPORTS; Body create or replace PACKAGE BODY BIREPORTS AS   FUNCTION beforeReportTrig return boolean AS   BEGIN       whereCols := ' and d.department_id = 100';     RETURN true;   END beforeReportTrig; END BIREPORTS; you'll notice the additional where clause (whereCols - declared as a public variable) is hard coded. I'll cover parameterizing that in my next post. If you can not wait, check the 10g docs for an example. I have my package compiling successfully in the db. Now, onto the BIP data model definition. 1. Create a new data model and go ahead and create your query(s) as you would normally. 2. In the query dialog box, add in the variables you want replaced at runtime using an ampersand rather than a colon e.g. &whereCols.   select     d.DEPARTMENT_NAME, ...  from    "OE"."EMPLOYEES" e,     "OE"."DEPARTMENTS" d  where   d."DEPARTMENT_ID"= e."DEPARTMENT_ID" &whereCols   Note that 'whereCols' matches the global variable name in our package. When you click OK to clear the dialog, you'll be asked for a default value for the variable, just use ' and 1=1' That leading space is important to keep the SQL valid ie required whitespace. This value will be used for the where clause if case its not set by the function code. 3. Now click on the Event Triggers tree node and create a new trigger of the type Before Data. Type in the default package name, in my example, 'BIREPORTS'. Then hit the update button to get BIP to fetch the valid functions.In my case I get to see the following: Select the BEFOREREPORTTRIG function (or your name) and shuttle it across. 4. Save your data model and now test it. For now, you can update the where clause via the plsql package. Next time ... parametrizing the dynamic clause.

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• Scripting with the Sun ZFS Storage 7000 Appliance

  - by Geoff Ongley

  The Sun ZFS Storage 7000 appliance has a user friendly and easy to understand graphical web based interface we call the "BUI" or "Browser User Interface".This interface is very useful for many tasks, but in some cases a script (or workflow) may be more appropriate, such as:Repetitive tasksTasks which work on (or obtain information about) a large number of shares or usersTasks which are triggered by an alert threshold (workflows)Tasks where you want a only very basic input, but a consistent output (workflows)The appliance scripting language is based on ECMAscript 3 (close to javascript). I'm not going to cover ECMAscript 3 in great depth (I'm far from an expert here), but I would like to show you some neat things you can do with the appliance, to get you started based on what I have found from my own playing around.I'm making the assumption you have some sort of programming background, and understand variables, arrays, functions to some extent - but of course if something is not clear, please let me know so I can fix it up or clarify it.Variable Declarations and ArraysVariablesECMAScript is a dynamically and weakly typed language. If you don't know what that means, google is your friend - but at a high level it means we can just declare variables with no specific type and on the fly.For example, I can declare a variable and use it straight away in the middle of my code, for example:projects=list();Which makes projects an array of values that are returned from the list(); function (which is usable in most contexts). With this kind of variable, I can do things like:projects.length (this property on array tells you how many objects are in it, good for for loops etc). Alternatively, I could say:projects=3;and now projects is just a simple number.Should we declare variables like this so loosely? In my opinion, the answer is no - I feel it is a better practice to declare variables you are going to use, before you use them - and given them an initial value. You can do so as follows:var myVariable=0;To demonstrate the ability to just randomly assign and change the type of variables, you can create a simple script at the cli as follows (bold for input):fishy10:> script("." to run)> run("cd /");("." to run)> run ("shares");("." to run)> var projects;("." to run)> projects=list();("." to run)> printf("Number of projects is: %d\n",projects.length);("." to run)> projects=152;("." to run)> printf("Value of the projects variable as an integer is now: %d\n",projects);("." to run)> .Number of projects is: 7Value of the projects variable as an integer is now: 152You can also confirm this behaviour by checking the typeof variable we are dealing with:fishy10:> script("." to run)> run("cd /");("." to run)> run ("shares");("." to run)> var projects;("." to run)> projects=list();("." to run)> printf("var projects is of type %s\n",typeof(projects));("." to run)> projects=152;("." to run)> printf("var projects is of type %s\n",typeof(projects));("." to run)> .var projects is of type objectvar projects is of type numberArraysSo you likely noticed that we have already touched on arrays, as the list(); (in the shares context) stored an array into the 'projects' variable.But what if you want to declare your own array? Easy! This is very similar to Java and other languages, we just instantiate a brand new "Array" object using the keyword new:var myArray = new Array();will create an array called "myArray".A quick example:fishy10:> script("." to run)> testArray = new Array();("." to run)> testArray[0]="This";("." to run)> testArray[1]="is";("." to run)> testArray[2]="just";("." to run)> testArray[3]="a";("." to run)> testArray[4]="test";("." to run)> for (i=0; i < testArray.length; i++)("." to run)> {("." to run)>    printf("Array element %d is %s\n",i,testArray[i]);("." to run)> }("." to run)> .Array element 0 is ThisArray element 1 is isArray element 2 is justArray element 3 is aArray element 4 is testWorking With LoopsFor LoopFor loops are very similar to those you will see in C, java and several other languages. One of the key differences here is, as you were made aware earlier, we can be a bit more sloppy with our variable declarations.The general way you would likely use a for loop is as follows:for (variable; test-case; modifier for variable){}For example, you may wish to declare a variable i as 0; and a MAX_ITERATIONS variable to determine how many times this loop should repeat:var i=0;var MAX_ITERATIONS=10;And then, use this variable to be tested against some case existing (has i reached MAX_ITERATIONS? - if not, increment i using i++);for (i=0; i < MAX_ITERATIONS; i++){ // some work to do}So lets run something like this on the appliance:fishy10:> script("." to run)> var i=0;("." to run)> var MAX_ITERATIONS=10;("." to run)> for (i=0; i < MAX_ITERATIONS; i++)("." to run)> {("." to run)>    printf("The number is %d\n",i);("." to run)> }("." to run)> .The number is 0The number is 1The number is 2The number is 3The number is 4The number is 5The number is 6The number is 7The number is 8The number is 9While LoopWhile loops again are very similar to other languages, we loop "while" a condition is met. For example:fishy10:> script("." to run)> var isTen=false;("." to run)> var counter=0;("." to run)> while(isTen==false)("." to run)> {("." to run)>    if (counter==10) ("." to run)>    { ("." to run)>            isTen=true;   ("." to run)>    } ("." to run)>    printf("Counter is %d\n",counter);("." to run)>    counter++;    ("." to run)> }("." to run)> printf("Loop has ended and Counter is %d\n",counter);("." to run)> .Counter is 0Counter is 1Counter is 2Counter is 3Counter is 4Counter is 5Counter is 6Counter is 7Counter is 8Counter is 9Counter is 10Loop has ended and Counter is 11So what do we notice here? Something has actually gone wrong - counter will technically be 11 once the loop completes... Why is this?Well, if we have a loop like this, where the 'while' condition that will end the loop may be set based on some other condition(s) existing (such as the counter has reached 10) - we must ensure that we  terminate this iteration of the loop when the condition is met - otherwise the rest of the code will be followed which may not be desirable. In other words, like in other languages, we will only ever check the loop condition once we are ready to perform the next iteration, so any other code after we set "isTen" to be true, will still be executed as we can see it was above.We can avoid this by adding a break into our loop once we know we have set the condition - this will stop the rest of the logic being processed in this iteration (and as such, counter will not be incremented). So lets try that again:fishy10:> script("." to run)> var isTen=false;("." to run)> var counter=0;("." to run)> while(isTen==false)("." to run)> {("." to run)>    if (counter==10) ("." to run)>    { ("." to run)>            isTen=true;   ("." to run)>            break;("." to run)>    } ("." to run)>    printf("Counter is %d\n",counter);("." to run)>    counter++;    ("." to run)> }("." to run)> printf("Loop has ended and Counter is %d\n", counter);("." to run)> .Counter is 0Counter is 1Counter is 2Counter is 3Counter is 4Counter is 5Counter is 6Counter is 7Counter is 8Counter is 9Loop has ended and Counter is 10Much better!Methods to Obtain and Manipulate DataGet MethodThe get method allows you to get simple properties from an object, for example a quota from a user. The syntax is fairly simple:var myVariable=get('property');An example of where you may wish to use this, is when you are getting a bunch of information about a user (such as quota information when in a shares context):var users=list();for(k=0; k < users.length; k++){     user=users[k];     run('select ' + user);     var username=get('name');     var usage=get('usage');     var quota=get('quota');...Which you can then use to your advantage - to print or manipulate infomation (you could change a user's information with a set method, based on the information returned from the get method). The set method is explained next.Set MethodThe set method can be used in a simple manner, similar to get. The syntax for set is:set('property','value'); // where value is a string, if it was a number, you don't need quotesFor example, we could set the quota on a share as follows (first observing the initial value):fishy10:shares default/test-geoff> script("." to run)> var currentQuota=get('quota');("." to run)> printf("Current Quota is: %s\n",currentQuota);("." to run)> set('quota','30G');("." to run)> run('commit');("." to run)> currentQuota=get('quota');("." to run)> printf("Current Quota is: %s\n",currentQuota);("." to run)> .Current Quota is: 0Current Quota is: 32212254720This shows us using both the get and set methods as can be used in scripts, of course when only setting an individual share, the above is overkill - it would be much easier to set it manually at the cli using 'set quota=3G' and then 'commit'.List MethodThe list method can be very powerful, especially in more complex scripts which iterate over large amounts of data and manipulate it if so desired. The general way you will use list is as follows:var myVar=list();Which will make "myVar" an array, containing all the objects in the relevant context (this could be a list of users, shares, projects, etc). You can then gather or manipulate data very easily.We could list all the shares and mountpoints in a given project for example:fishy10:shares another-project> script("." to run)> var shares=list();("." to run)> for (i=0; i < shares.length; i++)("." to run)> {("." to run)>    run('select ' + shares[i]);("." to run)>    var mountpoint=get('mountpoint');("." to run)>    printf("Share %s discovered, has mountpoint %s\n",shares[i],mountpoint);("." to run)>    run('done');("." to run)> }("." to run)> .Share and-another discovered, has mountpoint /export/another-project/and-anotherShare another-share discovered, has mountpoint /export/another-project/another-shareShare bob discovered, has mountpoint /export/another-projectShare more-shares-for-all discovered, has mountpoint /export/another-project/more-shares-for-allShare yep discovered, has mountpoint /export/another-project/yepWriting More Complex and Re-Usable CodeFunctionsThe best way to be able to write more complex code is to use functions to split up repeatable or reusable sections of your code. This also makes your more complex code easier to read and understand for other programmers.We write functions as follows:function functionName(variable1,variable2,...,variableN){}For example, we could have a function that takes a project name as input, and lists shares for that project (assuming we're already in the 'project' context - context is important!):function getShares(proj){        run('select ' + proj);        shares=list();        printf("Project: %s\n", proj);        for(j=0; j < shares.length; j++)        {                printf("Discovered share: %s\n",shares[i]);        }        run('done'); // exit selected project}Commenting your CodeLike any other language, a large part of making it readable and understandable is to comment it. You can use the same comment style as in C and Java amongst other languages.In other words, sngle line comments use://at the beginning of the comment.Multi line comments use:/*at the beginning, and:*/ at the end.For example, here we will use both:fishy10:> script("." to run)> // This is a test comment("." to run)> printf("doing some work...\n");("." to run)> /* This is a multi-line("." to run)> comment which I will span across("." to run)> three lines in total */("." to run)> printf("doing some more work...\n");("." to run)> .doing some work...doing some more work...Your comments do not have to be on their own, they can begin (particularly with single line comments this is handy) at the end of a statement, for examplevar projects=list(); // The variable projects is an array containing all projects on the system.Try and Catch StatementsYou may be used to using try and catch statements in other languages, and they can (and should) be utilised in your code to catch expected or unexpected error conditions, that you do NOT wish to stop your code from executing (if you do not catch these errors, your script will exit!):try{  // do some work}catch(err) // Catch any error that could occur{ // do something here under the error condition}For example, you may wish to only execute some code if a context can be reached. If you can't perform certain actions under certain circumstances, that may be perfectly acceptable.For example if you want to test a condition that only makes sense when looking at a SMB/NFS share, but does not make sense when you hit an iscsi or FC LUN, you don't want to stop all processing of other shares you may not have covered yet.For example we may wish to obtain quota information on all shares for all users on a share (but this makes no sense for a LUN):function getShareQuota(shar) // Get quota for each user of this share{        run('select ' + shar);        printf("  SHARE: %s\n", shar);        try        {                run('users');                printf("    %20s        %11s    %11s    %3s\n","Username","Usage(G)","Quota(G)","Quota(%)");                printf("    %20s        %11s    %11s    %4s\n","--------","--------","--------","----");                                users=list();                for(k=0; k < users.length; k++)                {                        user=users[k];                        getUserQuota(user);                }                run('done'); // exit user context        }        catch(err)        {                printf("    SKIPPING %s - This is NOT a NFS or CIFs share, not looking for users\n", shar);        }        run('done'); // done with this share}Running Scripts Remotely over SSHAs you have likely noticed, writing and running scripts for all but the simplest jobs directly on the appliance is not going to be a lot of fun.There's a couple of choices on what you can do here:Create scripts on a remote system and run them over sshCreate scripts, wrapping them in workflow code, so they are stored on the appliance and can be triggered under certain circumstances (like a threshold being reached)We'll cover the first one here, and then cover workflows later on (as these are for the most part just scripts with some wrapper information around them).Creating a SSH Public/Private SSH Key PairLog on to your handy Solaris box (You wouldn't be using any other OS, right? :P) and use ssh-keygen to create a pair of ssh keys. I'm storing this separate to my normal key:[geoff@lightning ~] ssh-keygen -t rsa -b 1024Generating public/private rsa key pair.Enter file in which to save the key (/export/home/geoff/.ssh/id_rsa): /export/home/geoff/.ssh/nas_key_rsaEnter passphrase (empty for no passphrase): Enter same passphrase again: Your identification has been saved in /export/home/geoff/.ssh/nas_key_rsa.Your public key has been saved in /export/home/geoff/.ssh/nas_key_rsa.pub.The key fingerprint is:7f:3d:53:f0:2a:5e:8b:2d:94:2a:55:77:66:5c:9b:14 geoff@lightningInstalling the Public Key on the ApplianceOn your Solaris host, observe the public key:[geoff@lightning ~] cat .ssh/nas_key_rsa.pub ssh-rsa AAAAB3NzaC1yc2EAAAABIwAAAIEAvYfK3RIaAYmMHBOvyhKM41NaSmcgUMC3igPN5gUKJQvSnYmjuWG6CBr1CkF5UcDji7v19jG3qAD5lAMFn+L0CxgRr8TNaAU+hA4/tpAGkjm+dKYSyJgEdMIURweyyfUFXoerweR8AWW5xlovGKEWZTAfvJX9Zqvh8oMQ5UJLUUc= geoff@lightningNow, copy and paste everything after "ssh-rsa" and before "user@hostname" - in this case, geoff@lightning. That is, this bit:AAAAB3NzaC1yc2EAAAABIwAAAIEAvYfK3RIaAYmMHBOvyhKM41NaSmcgUMC3igPN5gUKJQvSnYmjuWG6CBr1CkF5UcDji7v19jG3qAD5lAMFn+L0CxgRr8TNaAU+hA4/tpAGkjm+dKYSyJgEdMIURweyyfUFXoerweR8AWW5xlovGKEWZTAfvJX9Zqvh8oMQ5UJLUUc=Logon to your appliance and get into the preferences -> keys area for this user (root):[geoff@lightning ~] ssh [email protected]: Last login: Mon Dec  6 17:13:28 2010 from 192.168.0.2fishy10:> configuration usersfishy10:configuration users> select rootfishy10:configuration users root> preferences fishy10:configuration users root preferences> keysOR do it all in one hit:fishy10:> configuration users select root preferences keysNow, we create a new public key that will be accepted for this user and set the type to RSA:fishy10:configuration users root preferences keys> createfishy10:configuration users root preferences key (uncommitted)> set type=RSASet the key itself using the string copied previously (between ssh-rsa and user@host), and set the key ensuring you put double quotes around it (eg. set key="<key>"):fishy10:configuration users root preferences key (uncommitted)> set key="AAAAB3NzaC1yc2EAAAABIwAAAIEAvYfK3RIaAYmMHBOvyhKM41NaSmcgUMC3igPN5gUKJQvSnYmjuWG6CBr1CkF5UcDji7v19jG3qAD5lAMFn+L0CxgRr8TNaAU+hA4/tpAGkjm+dKYSyJgEdMIURweyyfUFXoerweR8AWW5xlovGKEWZTAfvJX9Zqvh8oMQ5UJLUUc="Now set the comment for this key (do not use spaces):fishy10:configuration users root preferences key (uncommitted)> set comment="LightningRSAKey" Commit the new key:fishy10:configuration users root preferences key (uncommitted)> commitVerify the key is there:fishy10:configuration users root preferences keys> lsKeys:NAME     MODIFIED              TYPE   COMMENT                                  key-000  2010-10-25 20:56:42   RSA    cycloneRSAKey                           key-001  2010-12-6 17:44:53    RSA    LightningRSAKey                         As you can see, we now have my new key, and a previous key I have created on this appliance.Running your Script over SSH from a Remote SystemHere I have created a basic test script, and saved it as test.ecma3:[geoff@lightning ~] cat test.ecma3 script// This is a test script, By Geoff Ongley 2010.printf("Testing script remotely over ssh\n");.Now, we can run this script remotely with our keyless login:[geoff@lightning ~] ssh -i .ssh/nas_key_rsa root@fishy10 < test.ecma3Pseudo-terminal will not be allocated because stdin is not a terminal.Testing script remotely over sshPutting it Together - An Example Completed Quota Gathering ScriptSo now we have a lot of the basics to creating a script, let us do something useful, like, find out how much every user is using, on every share on the system (you will recognise some of the code from my previous examples): script/************************************** Quick and Dirty Quota Check script ** Written By Geoff Ongley            ** 25 October 2010                    **************************************/function getUserQuota(usr){        run('select ' + usr);        var username=get('name');        var usage=get('usage');        var quota=get('quota');        var usage_g=usage / 1073741824; // convert bytes to gigabytes        var quota_g=quota / 1073741824; // as above        var quota_percent=0        if (quota > 0)        {                quota_percent=(usage / quota)*(100/1);        }        printf("    %20s        %8.2f           %8.2f           %d%%\n",username,usage_g,quota_g,quota_percent);        run('done'); // done with this selected user}function getShareQuota(shar){        //printf("DEBUG: selecting share %s\n", shar);        run('select ' + shar);        printf("  SHARE: %s\n", shar);        try        {                run('users');                printf("    %20s        %11s    %11s    %3s\n","Username","Usage(G)","Quota(G)","Quota(%)");                printf("    %20s        %11s    %11s    %4s\n","--------","--------","--------","--------");                                users=list();                for(k=0; k < users.length; k++)                {                        user=users[k];                        getUserQuota(user);                }                run('done'); // exit user context        }        catch(err)        {                printf("    SKIPPING %s - This is NOT a NFS or CIFs share, not looking for users\n", shar);        }        run('done'); // done with this share}function getShares(proj){        //printf("DEBUG: selecting project %s\n",proj);        run('select ' + proj);        shares=list();        printf("Project: %s\n", proj);        for(j=0; j < shares.length; j++)        {                share=shares[j];                getShareQuota(share);        }        run('done'); // exit selected project}function getProjects(){        run('cd /');        run('shares');        projects=list();                for (i=0; i < projects.length; i++)        {                var project=projects[i];                getShares(project);        }        run('done'); // exit context for all projects}getProjects();.Which can be run as follows, and will print information like this:[geoff@lightning ~/FISHWORKS_SCRIPTS] ssh -i ~/.ssh/nas_key_rsa root@fishy10 < get_quota_utilisation.ecma3Pseudo-terminal will not be allocated because stdin is not a terminal.Project: another-project  SHARE: and-another                Username           Usage(G)       Quota(G)    Quota(%)                --------           --------       --------    --------                  nobody            0.00            0.00        0%                 geoffro            0.05            0.00        0%                   Billy            0.10            0.00        0%                    root            0.00            0.00        0%            testing-user            0.05            0.00        0%  SHARE: another-share                Username           Usage(G)       Quota(G)    Quota(%)                --------           --------       --------    --------                    root            0.00            0.00        0%                  nobody            0.00            0.00        0%                 geoffro            0.05            0.49        9%            testing-user            0.05            0.02        249%                   Billy            0.10            0.29        33%  SHARE: bob                Username           Usage(G)       Quota(G)    Quota(%)                --------           --------       --------    --------                  nobody            0.00            0.00        0%                    root            0.00            0.00        0%  SHARE: more-shares-for-all                Username           Usage(G)       Quota(G)    Quota(%)                --------           --------       --------    --------                   Billy            0.10            0.00        0%            testing-user            0.05            0.00        0%                  nobody            0.00            0.00        0%                    root            0.00            0.00        0%                 geoffro            0.05            0.00        0%  SHARE: yep                Username           Usage(G)       Quota(G)    Quota(%)                --------           --------       --------    --------                    root            0.00            0.00        0%                  nobody            0.00            0.00        0%                   Billy            0.10            0.01        999%            testing-user            0.05            0.49        9%                 geoffro            0.05            0.00        0%Project: default  SHARE: Test-LUN    SKIPPING Test-LUN - This is NOT a NFS or CIFs share, not looking for users  SHARE: test-geoff                Username           Usage(G)       Quota(G)    Quota(%)                --------           --------       --------    --------                 geoffro            0.05            0.00        0%                    root            3.18           10.00        31%                    uucp            0.00            0.00        0%                  nobody            0.59            0.49        119%^CKilled by signal 2.Creating a WorkflowWorkflows are scripts that we store on the appliance, and can have the script execute either on request (even from the BUI), or on an event such as a threshold being met.Workflow BasicsA workflow allows you to create a simple process that can be executed either via the BUI interface interactively, or by an alert being raised (for some threshold being reached, for example).The basics parameters you will have to set for your "workflow object" (notice you're creating a variable, that embodies ECMAScript) are as follows (parameters is optional):name: A name for this workflowdescription: A Description for the workflowparameters: A set of input parameters (useful when you need user input to execute the workflow)execute: The code, the script itself to execute, which will be function (parameters)With parameters, you can specify things like this (slightly modified sample taken from the System Administration Guide):          ...parameters:        variableParam1:         {                             label: 'Name of Share',                             type: 'String'                  },                  variableParam2                  {                             label: 'Share Size',                             type: 'size'                  },execute: ....};  Note the commas separating the sections of name, parameters, execute, and so on. This is important!Also - there is plenty of properties you can set on the parameters for your workflow, these are described in the Sun ZFS Storage System Administration Guide.Creating a Basic Workflow from a Basic ScriptTo make a basic script into a basic workflow, you need to wrap the following around your script to create a 'workflow' object:var workflow = {name: 'Get User Quotas',description: 'Displays Quota Utilisation for each user on each share',execute: function() {// (basic script goes here, minus the "script" at the beginning, and "." at the end)}};However, it appears (at least in my experience to date) that the workflow object may only be happy with one function in the execute parameter - either that or I'm doing something wrong. As far as I can tell, after execute: you should only have a basic one function context like so:execute: function(){}To deal with this, and to give an example similar to our script earlier, I have created another simple quota check, to show the same basic functionality, but in a workflow format:var workflow = {name: 'Get User Quotas',description: 'Displays Quota Utilisation for each user on each share',execute: function () {        run('cd /');        run('shares');        projects=list();                for (i=0; i < projects.length; i++)        {                run('select ' + projects[i]);                shares=list('filesystem');                printf("Project: %s\n", projects[i]);                for(j=0; j < shares.length; j++)                {                        run('select ' +shares[j]);                        try                        {                                run('users');                                printf("  SHARE: %s\n", shares[j]);                                printf("    %20s        %11s    %11s    %3s\n","Username","Usage(G)","Quota(G)","Quota(%)");                                printf("    %20s        %11s    %11s    %4s\n","--------","--------","--------","-------");                                users=list();                                for(k=0; k < users.length; k++)                                {                                        run('select ' + users[k]);                                        username=get('name');                                        usage=get('usage');                                        quota=get('quota');                                        usage_g=usage / 1073741824; // convert bytes to gigabytes                                        quota_g=quota / 1073741824; // as above                                        quota_percent=0                                        if (quota > 0)                                        {                                                quota_percent=(usage / quota)*(100/1);                                        }                                        printf("    %20s        %8.2f   %8.2f   %d%%\n",username,usage_g,quota_g,quota_percent);                                        run('done');                                }                                run('done'); // exit user context                        }                        catch(err)                        {                        //      printf("    %s is a LUN, Not looking for users\n", shares[j]);                        }                        run('done'); // exit selected share context                }                run('done'); // exit project context        }        }};SummaryThe Sun ZFS Storage 7000 Appliance offers lots of different and interesting features to Sun/Oracle customers, including the world renowned Analytics. Hopefully the above will help you to think of new creative things you could be doing by taking advantage of one of the other neat features, the internal scripting engine!Some references are below to help you continue learning more, I'll update this post as I do the same! Enjoy...More information on ECMAScript 3A complete reference to ECMAScript 3 which will help you learn more of the details you may be interested in, can be found here:http://www.ecma-international.org/publications/files/ECMA-ST-ARCH/ECMA-262,%203rd%20edition,%20December%201999.pdfMore Information on Administering the Sun ZFS Storage 7000The Sun ZFS Storage 7000 System Administration guide can be a useful reference point, and can be found here:http://wikis.sun.com/download/attachments/186238602/2010_Q3_2_ADMIN.pdf

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• IIS7 web farm - local or shared content?

  - by rbeier

  We're setting up an IIS7 web farm with two servers. Should each server have its own local copy of the content, or should they pull content directly from a UNC share? What are the pros and cons of each approach? We currently have a single live server WEB1, with content stored locally on a separate partition. A job periodically syncs WEB1 to a standby server WEB2, using robocopy for content and msdeploy for config. If WEB1 goes down, Nagios notifies us, and we manually run a script to move the IP addresses to WEB2's network interface. Both servers are actually VMs running on separate VMWare ESX 4 hosts. The servers are domain-joined. We have around 50-60 live sites on WEB1 - mostly ASP.NET, with a few that are just static HTML. Most are low-traffic "microsites". A few have moderate traffic, but none are massive. We'd like to change this so both WEB1 and WEB2 are actively serving content. This is mainly for reliability - if WEB1 goes down, we don't want to have to manually intervene to fail things over. Spreading the load is also nice, but the load is not high enough right now for us to need this. We're planning to configure our firewall to balance traffic across the two servers. It will detect when a server goes down and will send all the traffic to the remaining live server. We're planning to use sticky sessions for now... eventually we may move to SQL Server session state and stateless load balancing. But we need a way for the servers to share content. We were originally planning to move all the content to a UNC share. Our storage provider says they can set up a highly available SMB share for us. So if we go the UNC route, the storage shouldn't be a single point of failure. But we're wondering about the downsides to this approach: We'll need to change the physical paths for each site and virtual directory. There are also some projects that have absolute paths in their web.config files - we'll have to update those as well. We'll need to create a domain user for the web servers to access the share, and grant that user appropriate permissions. I haven't looked into this yet - I'm not sure if the application pool identity needs to be changed to this user, or if there's another way to tell IIS to use this account when connecting to the share. Sites will no longer be able to access their content if there's ever an Active Directory problem. In general, it just seems a lot more complicated, with more moving parts that could break. Our storage provider would create a volume for us on their redundant SAN. If I understand correctly, this SAN volume would be mounted on a VM running in their redundant VMWare environment; this VM would then expose the SMB share to our web servers. On the other hand, a benefit of the shared content approach is that we'd only need to deploy code to one place, and there would never be a temporary inconsistency between multiple copies of the content. This thread is pretty interesting, though some of these people are working at a much larger scale. I've just been discussing content so far, but we also need to think about configuration. I don't know if we can just use DFS replication for the applicationHost.config and other files, or if it's best to use the shared configuration feature with the config on a UNC share. What do you think? Thanks for your help, Richard

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• svnstat script

  - by Kyle Hodgson

  So I'm building out a shell script to check out all of our relevant svn repositories for analysis in svnstat. I've gotten all of this to work manually, now I'm writing up a bash script in cygwin on my Vista laptop, as I intend to move this to a Linux server at some point. Edit: I gave up on this and wrote a simple .bat script. I'll figure out the Linux deployment some other way. Edit: added the sleep 30 and svn log commands. I can tell now, with the svn log command, that it's not getting to the svn log ... this time, it did Applications, and ran the log, and then check out Database, and froze. I'll put the sleep 30 before and after the log this time. co2.sh #!/bin/bash function checkout { mkdir $1 svn checkout svn://dev-server/$1 $1 svn log --verbose --xml >> svn.log $1 sleep 30 } cd /cygdrive/c/Users/My\ User/Documents/Repos/wc checkout Applications checkout Database checkout WebServer/www.mysite.com checkout WebServer/anotherhost.mysite.com checkout WebServer/AnotherApp checkout WebServer/thirdhost.mysite.com checkout WebServer/fourthhost.mysite.com checkout WebServer/WebServices It works, for the most part - but for some reason it has a tendency to stop working after a few repositories, usually right after finishing a repository before going to the next one. When it fails, it will not recover on its own. I've tried commenting out the svn line, it goes in and creates all the directories just fine when I do that - so its not that. I'm looking for direction as well as direct advice. Cygwin has been very stable for me, but I did start using the native rxvt instead of "bash in a cmd.exe window" recently. I don't think that's the problem, as I've left top on remote systems running all night and rxvt didn't seem to mind. Also I haven't done any bash scripting in cygwin so I suppose this might not be recommended; though I can't see why not. I don't want all of WebServer, hence me only checking out certain folders like that. What I suspect is that something is hanging up the svn checkout. Any ideas here? Edit: this time when I hit ctrl+z to cancel out, I forgot I was on Windows and typed ps to see if the job was still running; and as you can see there are lots of svn processes hanging around... strange. Kyle Hodgson@KyleHodgson-PC ~/winUser/Documents/Repos $ Kyle Hodgson@KyleHodgson-PC ~/winUser/Documents/Repos $ jobs [1]- Stopped bash co2.sh [2]+ Stopped ./co2.sh Kyle Hodgson@KyleHodgson-PC ~/winUser/Documents/Repos $ kill %1 [1]- Stopped bash co2.sh Kyle Hodgson@KyleHodgson-PC ~/winUser/Documents/Repos $ [1]- Terminated bash co2.sh Kyle Hodgson@KyleHodgson-PC ~/winUser/Documents/Repos $ Kyle Hodgson@KyleHodgson-PC ~/winUser/Documents/Repos $ Kyle Hodgson@KyleHodgson-PC ~/winUser/Documents/Repos $ ps PID PPID PGID WINPID TTY UID STIME COMMAND 7872 1 7872 2340 0 1000 Jun 29 /usr/bin/svn 7752 1 6140 7828 1 1000 Jun 29 /usr/bin/svn 6192 1 5044 2192 1 1000 Jun 30 /usr/bin/svn 7292 1 7452 1796 1 1000 Jun 30 /usr/bin/svn 6236 1 7304 7468 2 1000 Jul 2 /usr/bin/svn 1564 1 5032 7144 2 1000 Jul 2 /usr/bin/svn 9072 1 3960 6276 3 1000 Jul 3 /usr/bin/svn 5876 1 5876 5876 con 1000 11:22:10 /usr/bin/rxvt 924 5876 924 10192 4 1000 11:22:10 /usr/bin/bash 7212 1 7332 5584 4 1000 13:17:54 /usr/bin/svn 9412 1 5480 8840 4 1000 15:38:16 /usr/bin/svn S 8128 924 8128 9452 4 1000 17:38:05 /usr/bin/bash 9132 8128 8128 8172 4 1000 17:43:25 /usr/bin/svn 3512 1 3512 3512 con 1000 17:43:50 /usr/bin/rxvt I 10200 3512 10200 6616 5 1000 17:43:51 /usr/bin/bash 9732 1 9732 9732 con 1000 17:45:55 /usr/bin/rxvt 3148 9732 3148 8976 6 1000 17:45:55 /usr/bin/bash 5856 3148 5856 876 6 1000 17:51:00 /usr/bin/vim 7736 924 7736 8036 4 1000 17:53:26 /usr/bin/ps Kyle Hodgson@KyleHodgson-PC ~/winUser/Documents/Repos $ jobs [2]+ Stopped ./co2.sh Kyle Hodgson@KyleHodgson-PC ~/winUser/Documents/Repos $ Here's an strace on the PID of the hung svn program, it's been like this for hours. Looks like its just doing nothing. I keep suspecting that some interruption on the server is causing this; does svn have a locking mechanism I'm not aware of? Kyle Hodgson@KyleHodgson-PC ~/winUser/Documents/Repos $ strace -p 7304 ********************************************** Program name: C:\cygwin\bin\svn.exe (pid 7304, ppid 6408) App version: 1005.25, api: 0.156 DLL version: 1005.25, api: 0.156 DLL build: 2008-06-12 19:34 OS version: Windows NT-6.0 Heap size: 402653184 Date/Time: 2009-07-06 18:20:11 **********************************************

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• Why do we get a sudden spike in response times?

  - by Christian Hagelid

  We have an API that is implemented using ServiceStack which is hosted in IIS. While performing load testing of the API we discovered that the response times are good but that they deteriorate rapidly as soon as we hit about 3,500 concurrent users per server. We have two servers and when hitting them with 7,000 users the average response times sit below 500ms for all endpoints. The boxes are behind a load balancer so we get 3,500 concurrents per server. However as soon as we increase the number of total concurrent users we see a significant increase in response times. Increasing the concurrent users to 5,000 per server gives us an average response time per endpoint of around 7 seconds. The memory and CPU on the servers are quite low, both while the response times are good and when after they deteriorate. At peak with 10,000 concurrent users the CPU averages just below 50% and the RAM sits around 3-4 GB out of 16. This leaves us thinking that we are hitting some kind of limit somewhere. The below screenshot shows some key counters in perfmon during a load test with a total of 10,000 concurrent users. The highlighted counter is requests/second. To the right of the screenshot you can see the requests per second graph becoming really erratic. This is the main indicator for slow response times. As soon as we see this pattern we notice slow response times in the load test. How do we go about troubleshooting this performance issue? We are trying to identify if this is a coding issue or a configuration issue. Are there any settings in web.config or IIS that could explain this behaviour? The application pool is running .NET v4.0 and the IIS version is 7.5. The only change we have made from the default settings is to update the application pool Queue Length value from 1,000 to 5,000. We have also added the following config settings to the Aspnet.config file: <system.web> <applicationPool maxConcurrentRequestsPerCPU="5000" maxConcurrentThreadsPerCPU="0" requestQueueLimit="5000" /> </system.web> More details: The purpose of the API is to combine data from various external sources and return as JSON. It is currently using an InMemory cache implementation to cache individual external calls at the data layer. The first request to a resource will fetch all data required and any subsequent requests for the same resource will get results from the cache. We have a 'cache runner' that is implemented as a background process that updates the information in the cache at certain set intervals. We have added locking around the code that fetches data from the external resources. We have also implemented the services to fetch the data from the external sources in an asynchronous fashion so that the endpoint should only be as slow as the slowest external call (unless we have data in the cache of course). This is done using the System.Threading.Tasks.Task class. Could we be hitting a limitation in terms of number of threads available to the process?

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• Varnish cached 'MISS status' object?

  - by Hesey

  My site uses nginx, varnish, jboss. And some url will be cached by varnish, it depends a response header from jboss. The first time, jboss tells varnish doesn't cache this url. Then the second request, jboss tells varnish to cache, but varnish won't cache it. I used varnishstat and found that 1 object is cached in Varnish, is that the 'MISS status' object? I remove grace code and the problem still exists. When I PURGE this url, varnish works fine and cache the url then. But I can't PURGE so much urls every startup time, how can I fix this? The configuration: acl local { "localhost"; } backend default { .host = "localhost"; .port = "8080"; .probe = { .url = "/preload.htm"; .interval = 3s; .timeout = 1s; .window = 5; .threshold = 3; } } sub vcl_deliver { if (req.request == "PURGE") { remove resp.http.X-Varnish; remove resp.http.Via; remove resp.http.Age; remove resp.http.Content-Type; remove resp.http.Server; remove resp.http.Date; remove resp.http.Accept-Ranges; remove resp.http.Connection; set resp.http.keeplive="true"; } else { if (obj.hits > 0) { set resp.http.X-Cache = "HIT"; } else { set resp.http.X-Cache = "MISS"; } } } sub vcl_recv { if(req.url ~ "/check.htm"){ error 404 "N"; } if( req.http.host ~ "store." || req.request == "POST"){ return (pipe); } if (req.backend.healthy) { set req.grace = 30s; } else { set req.grace = 10m; } set req.http.x-cacheKey = "0"; if(req.url ~ "/shop/view_shop.htm" || req.url ~ "/shop/viewShop.htm" || req.url ~ "/index.htm"){ if(req.url ~ "search=y"){ set req.http.x-cacheKey = req.http.host + "/search.htm"; }else if(req.url !~ "bbs=y" && req.url !~ "shopIntro=y" && req.url !~ "shop_intro=y"){ set req.http.x-cacheKey = req.http.host + "/index.htm"; } }else if(req.url ~ "/search"){ set req.http.x-cacheKey = req.http.host + "/search.htm"; } if( req.http.x-cacheKey == "0" && req.url !~ "/i/"){ return (pipe); } if (req.request == "PURGE") { if (client.ip ~ local) { return (lookup); } else { error 405 "Not allowed."; } } if (req.url ~ "/i/") { set req.http.x-shop-url = req.original_url; }else { unset req.http.cookie; } } sub vcl_fetch { set beresp.grace = 10m; #unset beresp.http.x-cacheKey; if (req.url ~ "/i/" || req.url ~ "status" ){ set beresp.ttl = 0s; /* ttl=0 for dynamic content */ } else if(beresp.http.x-varnish-cache != "1"){ set beresp.do_esi = true; /* Do ESI processing */ set beresp.ttl = 0s; unset beresp.http.set-cookie; } else { set beresp.do_esi = true; /* Do ESI processing */ set beresp.ttl = 1800s; unset beresp.http.set-cookie; } } sub vcl_hash { hash_data(req.http.x-cacheKey); return (hash); } sub vcl_error { if (req.request == "PURGE") { return (deliver); } else { set obj.http.Content-Type = "text/html; charset=gbk"; synthetic {"<!--ve-->"}; return (deliver); } } sub vcl_hit { if (req.request == "PURGE") { set obj.ttl = 0s; error 200 "Purged."; } } sub vcl_miss { if (req.request == "PURGE") { error 404 "N"; } }

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• Diagnosing Solaris 8 server memory and swap space usage

  - by datSilencer

  Hello everyone. Essentially, my question is related to memory allocation for Solaris virtual machines. I am running a couple of old Sun ONE 6 Java web servers on two Solaris 8 virtual machines. I see that there's a reasonable amount of swap space being used, but I'm not exactly sure if this could indicate a need to add more RAM to these machines. At service peak hours (mornings usually), the response time of the web application these servers host jumps up to at most 11 seconds (somewhat detrimental for a relatively simple web page loading action). Average response time at non peak times is about 5 seconds. What would you be able to infer about the RAM usage for these machines from the ouput below? Is this information reasonably sufficient? Or would I need to run some other commands to rule out server memory starvation? Finally, since there is a Java application at the core of the setup, I've also thought about: 1) Trace the heap's Object allocation to detect potential memory leaks. 2) Do some performance profiling to see if this instead related to networking delays. I mention this since the application talks with a single Oracle Database, but I would doubt this to be the case since they're pretty close from a network segmentation perspective. I appreciate any kind of insight and feedback you could provide. Thanks for your time and help. Server 1: 40 processes: 38 sleeping, 1 zombie, 1 on cpu CPU states: 99.1% idle, 0.4% user, 0.4% kernel, 0.0% iowait, 0.0% swap Memory: 2048M real, 295M free, 865M swap in use, 3788M swap free PID USERNAME THR PRI NICE SIZE RES STATE TIME CPU COMMAND 12676 webservd 112 29 10 616M 242M sleep 103:37 0.48% webservd 18317 root 1 59 0 23M 19M sleep 67:24 0.08% perl 9479 support 1 59 0 6696K 2448K cpu/1 0:11 0.05% top 8012 root 10 59 0 34M 704K sleep 80:54 0.04% java 1881 root 33 29 10 110M 13M sleep 33:03 0.02% webservd 7808 root 1 59 0 83M 67M sleep 7:59 0.00% perl 1461 root 20 59 0 5328K 1392K sleep 6:49 0.00% syslogd 1691 root 2 59 0 27M 680K sleep 4:22 0.00% webservd 24386 root 1 59 0 15M 11M sleep 2:50 0.00% perl 23259 root 1 59 0 11M 4240K sleep 2:42 0.00% perl 24718 root 1 59 0 11M 5464K sleep 2:29 0.00% perl 22810 root 1 59 0 19M 11M sleep 2:21 0.00% perl 24451 root 1 53 2 11M 3800K sleep 2:18 0.00% perl 18501 root 1 56 1 11M 3960K sleep 2:18 0.00% perl 14450 root 1 56 1 15M 6920K sleep 1:49 0.00% perl Server 2 42 processes: 40 sleeping, 1 zombie, 1 on cpu CPU states: 98.8% idle, 0.4% user, 0.8% kernel, 0.0% iowait, 0.0% swap Memory: 1024M real, 31M free, 554M swap in use, 3696M swap free PID USERNAME THR PRI NICE SIZE RES STATE TIME CPU COMMAND 5607 webservd 74 29 10 284M 173M sleep 20:14 0.21% webservd 15919 support 1 59 0 4056K 2520K cpu/1 0:08 0.09% top 13138 root 10 59 0 34M 1952K sleep 210:51 0.08% java 13753 root 1 59 0 22M 12M sleep 170:15 0.07% perl 22979 root 33 29 10 112M 7864K sleep 85:07 0.04% webservd 22930 root 1 59 0 3424K 1552K sleep 17:47 0.01% xntpd 22978 root 2 59 0 27M 2296K sleep 10:49 0.00% webservd 13571 root 1 59 0 9400K 5112K sleep 5:52 0.00% perl 5606 root 2 29 10 29M 9056K sleep 0:36 0.00% webservd 15910 support 1 59 0 9128K 2616K sleep 0:00 0.00% sshd 13106 root 1 59 0 82M 3520K sleep 7:47 0.00% perl 13547 root 1 59 0 12M 5528K sleep 6:38 0.00% perl 13518 root 1 59 0 9336K 3792K sleep 6:24 0.00% perl 13399 root 1 56 1 8072K 3616K sleep 5:18 0.00% perl 13557 root 1 53 2 8248K 3624K sleep 5:12 0.00% perl

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• Have I pushed the limits of my current VPS or is there room for optimization?

  - by JRameau

  I am currently on a mediatemple DV server (basic) 512mb dedicated ram, this is a CentOS based VPS with Plesk and Virtuozzo. My experience with it from day 1 has been bad and I only could sooth my server issues with several caching "Band-aids," but my sites are not as small as they were a year ago either so the issues have worsen. I have 3 Drupal installs running on separate (plesk) domains, 1 of those drupal installs is a multisite, that consists of 5-6 sites 2 of those sites are bringing in actual traffic. Those caching "Band-aids" I mentioned are APC, which seemed to help alot initially, and Drupal's Boost, which is considered a poorman's Varnish, it makes all my pages static for anonymous users. Last 30day combined estimate on Google Ananlytics: 90k visitors 260k pageviews. Issue: alot of downtime, I am continually checking if my sites are up, and lately I have been finding it down more than 3 times daily. Restarting Apache will bring it back up, for some time. I have google search every error message and looked up ways to optimize my DV server, and I am beyond stump what is my next move. Is this server bad, have I hit a impossibly low restriction such as the 12mb kernel memory barrier (kmemsize), is it on my end, do I need to optimize some more? *I have provided as much information as I can below, any help or suggestions given will be appreciated Common Error messages I see in the log: [error] (12)Cannot allocate memory: fork: Unable to fork new process [error] make_obcallback: could not import mod_python.apache.\n Traceback (most recent call last): File "/usr/lib/python2.4/site-packages/mod_python/apache.py", line 21, in ? import traceback File "/usr/lib/python2.4/traceback.py", line 3, in ? import linecache ImportError: No module named linecache [error] python_handler: no interpreter callback found. [warn-phpd] mmap cache can't open /var/www/vhosts/***/httpdocs/*** - Too many open files in system (pid ***) [alert] Child 8125 returned a Fatal error... Apache is exiting! [emerg] (43)Identifier removed: couldn't grab the accept mutex [emerg] (22)Invalid argument: couldn't release the accept mutex cat /proc/user_beancounters: Version: 2.5 uid resource held maxheld barrier limit failcnt 41548: kmemsize 4582652 5306699 12288832 13517715 21105036 lockedpages 0 0 600 600 0 privvmpages 38151 42676 229036 249036 0 shmpages 16274 16274 17237 17237 2 dummy 0 0 0 0 0 numproc 43 46 300 300 0 physpages 27260 29528 0 2147483647 0 vmguarpages 0 0 131072 2147483647 0 oomguarpages 27270 29538 131072 2147483647 0 numtcpsock 21 29 300 300 0 numflock 8 8 480 528 0 numpty 1 1 30 30 0 numsiginfo 0 1 1024 1024 0 tcpsndbuf 648440 675272 2867477 4096277 1711499 tcprcvbuf 301620 359716 2867477 4096277 0 othersockbuf 4472 4472 1433738 2662538 0 dgramrcvbuf 0 0 1433738 1433738 0 numothersock 12 12 300 300 0 dcachesize 0 0 2684271 2764800 0 numfile 3447 3496 6300 6300 3872 dummy 0 0 0 0 0 dummy 0 0 0 0 0 dummy 0 0 0 0 0 numiptent 14 14 200 200 0 TOP: (In January the load avg was really high 3-10, I was able to bring it down where it is currently is by giving APC more memory play around with) top - 16:46:07 up 2:13, 1 user, load average: 0.34, 0.20, 0.20 Tasks: 40 total, 2 running, 37 sleeping, 0 stopped, 1 zombie Cpu(s): 0.3% us, 0.1% sy, 0.0% ni, 99.7% id, 0.0% wa, 0.0% hi, 0.0% si Mem: 916144k total, 156668k used, 759476k free, 0k buffers Swap: 0k total, 0k used, 0k free, 0k cached MySQLTuner: (after optimizing every table and repairing any table with overage I got the fragmented count down to 86) [--] Data in MyISAM tables: 285M (Tables: 1105) [!!] Total fragmented tables: 86 [--] Up for: 2h 44m 38s (409K q [41.421 qps], 6K conn, TX: 1B, RX: 174M) [--] Reads / Writes: 79% / 21% [--] Total buffers: 58.0M global + 2.7M per thread (100 max threads) [!!] Query cache prunes per day: 675307 [!!] Temporary tables created on disk: 35% (7K on disk / 20K total)

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• Netgear VPN endpoint drops connectivity to single IP address

  - by Justin Bowers

  I'm having a strange issue with one of the networks I manage recently. We have about 14 different networks connected together through a Netgear hardware VPN. Everything has been running fine (other than standard connectivity problems) for a few years now, but I've hit a wall with a problem that's just cropped up at one of the VPN endpoint locations. Our primary VPN network is on the 192.168.1.0/24 subnet and our other 13 networks are on the 192.168.2.0/24 - 192.168.14.0/24 subnets. We run a terminal server on the 192.168.1.0/24 network with IP address 192.168.1.100. Starting Thursday of last week, we had a problem with connectivity of the 192.168.2.0/24 network to 192.168.1.100. When troubleshooting the problem, I found that Network 2 (192.168.2.0/24) still had connectivity to the Internet as well as VPN connectivity to Network 1 (192.168.1.0/24). We could ping and connect to any other device other than the server with IP address 192.168.1.100. Also, none of our networks had an issue accessing 192.168.1.100. I ran a scan on Network 2 after assigning static IP addresses to one of the workstations but received no response from 192.168.1.100 (looking for possibly a new device that someone had plugged into Network 2 that had a duplicate IP address with the server). Asking the staff, noone had reported connecting a new device to Network 2 as well. I then assigned a secondary IP address of 192.168.1.88 to the server and could ping and connect to the secondary IP address from Network 2, but still couldn't access it via 192.168.1.100. I then just rebooted the Netgear VPN Firewall (FVS318v3) and after it came back up, connectivity to 192.168.1.100 was restored. Beforehand, when checking for devices with a possible duplicate IP address, I did run a check for available wireless access points and stations and found none (our wireless is secured via MAC address access control through a WG102 device). I thought that it may have been a fluke for some reason since everything came back up after a power cycle of the VPN Firewall. Things ran fine for a few days until this afternoon, when the problem happened again. One of our users claimed that they had connectivity problems to the server and after connecting to the computer, I found that I couldn't ping the server address anymore. I could still ping the alternate IP address of the server though, so I went ahead and rebooted the VPN firewall again and connectivity was restored. Unfortunately, I can't find anything in the security or VPN logs of the firewall that helps point me in the right direction, so I thought I would go ahead and ask to see if anyone else has any other insight into why we've started having this problem. I am aware that it could still be a device with a duplicate IP address of the server on Network 2, but every employee claim states that there's been no such new device brought in to the network. I know this is a long read, but any help is appreciated! Thanks, Justin

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