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• Moving StarterSTS to the (Azure) Cloud

  - by Your DisplayName here!

  Quite some people asked me about an Azure version of StarterSTS. While I kinda knew what I had to do to make the move, I couldn’t find the time. Until recently. This blog post briefly documents the necessary changes and design decisions for the next version of StarterSTS which will work both on-premise and on Azure. Provider Fortunately StarterSTS is already based on the idea of “providers”. Authentication, roles and claims generation is based on the standard ASP.NET provider infrastructure. This makes the migration to different data stores less painful. In my case I simply moved the ASP.NET provider database to SQL Azure and still use the standard SQL Server based membership, roles and profile provider. In addition StarterSTS has its own providers to abstract resource access for certificates, relying party registration, client certificate registration and delegation. So I only had to provide new implementations. Signing and SSL keys now go in the Azure certificate store and user mappings (client certificates and delegation settings) have been moved to Azure table storage. The one thing I didn’t anticipate when I originally wrote StarterSTS was the need to also encapsulate configuration. Currently configuration is “locked” to the standard .NET configuration system. The new version will have a pluggable SettingsProvider with versions for .NET configuration as well as Azure service configuration. If you want to externalize these settings into e.g. a database, it is now just a matter of supplying a corresponding provider. Moving between the on-premise and Azure version will be just a matter of using different providers. URL Handling Another thing that’s substantially different on Azure (and load balanced scenarios in general) is the handling of URLs. In farm scenarios, the standard APIs like ASP.NET’s Request.Url return the current (internal) machine name, but you typically need the address of the external facing load balancer. There’s a hotfix for WCF 3.5 (included in v4) that fixes this for WCF metadata. This was accomplished by using the HTTP Host header to generate URLs instead of the local machine name. I now use the same approach for generating WS-Federation metadata as well as information card files. New Features I introduced a cache provider. Since we now have slightly more expensive lookups (e.g. relying party data from table storage), it makes sense to cache certain data in the front end. The default implementation uses the ASP.NET web cache and can be easily extended to use products like memcached or AppFabric Caching. Starting with the relying party provider, I now also provide a read/write interface. This allows building management interfaces on top of this provider. I also include a (very) simple web page that allows working with the relying party provider data. I guess I will use the same approach for other providers in the future as well. I am also doing some work on the tracing and health monitoring area. Especially important for the Azure version. Stay tuned.

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• What's new in Servlet 3.1 ? - Java EE 7 moving forward

  - by arungupta

  Servlet 3.0 was released as part of Java EE 6 and made huge changes focused at ease-of-use. The idea was to leverage the latest language features such as annotations and generics and modernize how Servlets can be written. The web.xml was made as optional as possible. Servet 3.1 (JSR 340), scheduled to be part of Java EE 7, is an incremental release focusing on couple of key features and some clarifications in the specification. The main features of Servlet 3.1 are explained below: Non-blocking I/O - Servlet 3.0 allowed asynchronous request processing but only traditional I/O was permitted. This can restrict scalability of your applications. Non-blocking I/O allow to build scalable applications. TOTD #188 provide more details about how non-blocking I/O can be done using Servlet 3.1. HTTP protocol upgrade mechanism - Section 14.42 in the HTTP 1.1 specification (RFC 2616) defines an upgrade mechanism that allows to transition from HTTP 1.1 to some other, incompatible protocol. The capabilities and nature of the application-layer communication after the protocol change is entirely dependent upon the new protocol chosen. After an upgrade is negotiated between the client and the server, the subsequent requests use the new chosen protocol for message exchanges. A typical example is how WebSocket protocol is upgraded from HTTP as described in Opening Handshake section of RFC 6455. The decision to upgrade is made in Servlet.service method. This is achieved by adding a new method: HttpServletRequest.upgrade and two new interfaces: javax.servlet.http.HttpUpgradeHandler and javax.servlet.http.WebConnection. TyrusHttpUpgradeHandler shows how WebSocket protocol upgrade is done in Tyrus (Reference Implementation for Java API for WebSocket). Security enhancements Applying run-as security roles to #init and #destroy methods Session fixation attack by adding HttpServletRequest.changeSessionId and a new interface HttpSessionIdListener. You can listen for any session id changes using these methods. Default security semantic for non-specified HTTP method in <security-constraint> Clarifying the semantics if a parameter is specified in the URI and payload Miscellaneous ServletResponse.reset clears any data that exists in the buffer as well as the status code, headers. In addition, Servlet 3.1 will also clears the state of calling getServletOutputStream or getWriter. ServletResponse.setCharacterEncoding: Sets the character encoding (MIME charset) of the response being sent to the client, for example, to UTF-8. Relative protocol URL can be specified in HttpServletResponse.sendRedirect. This will allow a URL to be specified without a scheme. That means instead of specifying "http://anotherhost.com/foo/bar.jsp" as a redirect address, "//anotherhost.com/foo/bar.jsp" can be specified. In this case the scheme of the corresponding request will be used. Clarification in HttpServletRequest.getPart and .getParts without multipart configuration. Clarification that ServletContainerInitializer is independent of metadata-complete and is instantiated per web application. A complete replay of What's New in Servlet 3.1: An Overview from JavaOne 2012 can be seen here (click on CON6793_mp4_6793_001 in Media). Each feature will be added to the JSR subject to EG approval. You can share your feedback to [email protected]. Here are some more references for you: Servlet 3.1 Public Review Candidate Downloads Servlet 3.1 PR Candidate Spec Servlet 3.1 PR Candidate Javadocs Servlet Specification Project JSR Expert Group Discussion Archive Java EE 7 Specification Status Several features have already been integrated in GlassFish 4 Promoted Builds. Have you tried any of them ? Here are some other Java EE 7 primers published so far: Concurrency Utilities for Java EE (JSR 236) Collaborative Whiteboard using WebSocket in GlassFish 4 (TOTD #189) Non-blocking I/O using Servlet 3.1 (TOTD #188) What's New in EJB 3.2 ? JPA 2.1 Schema Generation (TOTD #187) WebSocket Applications using Java (JSR 356) Jersey 2 in GlassFish 4 (TOTD #182) WebSocket and Java EE 7 (TOTD #181) Java API for JSON Processing (JSR 353) JMS 2.0 Early Draft (JSR 343) And of course, more on their way! Do you want to see any particular one first ?

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• Customer Loyalty vs. Customer Engagement: Who Cares?

  - by Jeb Dasteel-Oracle

  Have you read the recent Forbes OracleVoice blog titled Customer Loyalty is Dead. Long Live Engagement!? If you haven’t, take a look. This article prompted lots of conversation in the social realm. Many who read the article voiced their reactions to the headline and now I’m jumping in to add my view. Normal 0 false false false EN-US X-NONE X-NONE Customer loyalty is still key. It’s the effect and engagement is the cause. We at least know that to be true for our customers. We are in an age where customers are demanding to be heard. We need them to be actively involved – or engaged – as well. Greater levels of customer engagement, properly targeted, positively correlate with satisfaction. Our data has shown us this over and over. Satisfied customers are more loyal and more willing to vocalize their satisfaction through referencing, and are more likely to purchase again, all of which in turn drives incremental revenue – from the customer doing the referencing AND the customer on the receiving end of that reference. Turning this around completely, if we begin to see the level of a customer’s engagement start to wane, this is an indicator that their satisfaction, loyalty, and future revenue are likely at risk. At Oracle, we’ve put in place many programs to target, encourage, and then track engagement, allowing us to measure engagement as a determinant of loyalty. Some of these programs include our Key Accounts, solution design and architectural, Executive Sponsorship, as well as executive advisory boards. Specific programs allow us to engage specific contacts within specific customer organizations (based on role) and then systematically track their engagement activities over time, along side of tracking customer satisfaction, loyalty, referenceability, and incremental revenue contribution. Continuous measurement of engagement allows us to better understand customer views of what it means to partner with a provider and adjust program participation to better meet the needs of the partnership. We can also track across customer segments, and design new programs that are even more effective than the ones we have in place today. In case you missed any of my previous Forbes articles, I’ve included links below for easy access. Award-Winning Companies Put Customers First The Power of Peer Networks: 5 Reasons to Get (and Stay) Involved Technology At Work: Traveling In Style Customer Central: 8 Strategies for Putting Customers at the Core of Your Business Technology at Work: Five Companies Doing IT Right /* 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-top:0in; mso-para-margin-right:0in; mso-para-margin-bottom:10.0pt; mso-para-margin-left:0in; line-height:115%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;}

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• Using WKA in Large Coherence Clusters (Disabling Multicast)

  - by jpurdy

  Disabling hardware multicast (by configuring well-known addresses aka WKA) will place significant stress on the network. For messages that must be sent to multiple servers, rather than having a server send a single packet to the switch and having the switch broadcast that packet to the rest of the cluster, the server must send a packet to each of the other servers. While hardware varies significantly, consider that a server with a single gigabit connection can send at most ~70,000 packets per second. To continue with some concrete numbers, in a cluster with 500 members, that means that each server can send at most 140 cluster-wide messages per second. And if there are 10 cluster members on each physical machine, that number shrinks to 14 cluster-wide messages per second (or with only mild hyperbole, roughly zero). It is also important to keep in mind that network I/O is not only expensive in terms of the network itself, but also the consumption of CPU required to send (or receive) a message (due to things like copying the packet bytes, processing a interrupt, etc). Fortunately, Coherence is designed to rely primarily on point-to-point messages, but there are some features that are inherently one-to-many: Announcing the arrival or departure of a member Updating partition assignment maps across the cluster Creating or destroying a NamedCache Invalidating a cache entry from a large number of client-side near caches Distributing a filter-based request across the full set of cache servers (e.g. queries, aggregators and entry processors) Invoking clear() on a NamedCache The first few of these are operations that are primarily routed through a single senior member, and also occur infrequently, so they usually are not a primary consideration. There are cases, however, where the load from introducing new members can be substantial (to the point of destabilizing the cluster). Consider the case where cluster in the first paragraph grows from 500 members to 1000 members (holding the number of physical machines constant). During this period, there will be 500 new member introductions, each of which may consist of several cluster-wide operations (for the cluster membership itself as well as the partitioned cache services, replicated cache services, invocation services, management services, etc). Note that all of these introductions will route through that one senior member, which is sharing its network bandwidth with several other members (which will be communicating to a lesser degree with other members throughout this process). While each service may have a distinct senior member, there's a good chance during initial startup that a single member will be the senior for all services (if those services start on the senior before the second member joins the cluster). It's obvious that this could cause CPU and/or network starvation. In the current release of Coherence (3.7.1.3 as of this writing), the pure unicast code path also has less sophisticated flow-control for cluster-wide messages (compared to the multicast-enabled code path), which may also result in significant heap consumption on the senior member's JVM (from the message backlog). This is almost never a problem in practice, but with sufficient CPU or network starvation, it could become critical. For the non-operational concerns (near caches, queries, etc), the application itself will determine how much load is placed on the cluster. Applications intended for deployment in a pure unicast environment should be careful to avoid excessive dependence on these features. Even in an environment with multicast support, these operations may scale poorly since even with a constant request rate, the underlying workload will increase at roughly the same rate as the underlying resources are added. Unless there is an infrastructural requirement to the contrary, multicast should be enabled. If it can't be enabled, care should be taken to ensure the added overhead doesn't lead to performance or stability issues. This is particularly crucial in large clusters.

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• Access Control Lists for Roles

  - by Kyle Hatlestad

  Back in an earlier post, I wrote about how to enable entity security (access control lists, aka ACLs) for UCM 11g PS3.  Well, there was actually an additional security option that was included in that release but not fully supported yet (only for Fusion Applications).  It's the ability to define Roles as ACLs to entities (documents and folders).  But now in PS5, this security option is now fully supported.   The benefit of defining Roles for ACLs is that those user roles come from the enterprise security directory (e.g. OID, Active Directory, etc) and thus the WebCenter Content administrator does not need to define them like they do with ACL Groups (Aliases).  So it's a bit of best of both worlds.  Users are managed through the LDAP repository and are automatically granted/denied access through their group membership which are mapped to Roles in WCC.  A different way to think about it is being able to add multiple Accounts to content items...which I often get asked about.  Because LDAP groups can map to Accounts, there has always been this association between the LDAP groups and access to the entity in WCC.  But that mapping had to define the specific level of access (RWDA) and you could only apply one Account per content item or folder.  With Roles for ACLs, it basically takes away both of those restrictions by allowing users to define more then one Role and define the level of access on-the-fly. To turn on ACLs for Roles, there is a component to enable.  On the Component Manager page, click the 'advanced component manager' link in the description paragraph at the top.   In the list of Disabled Components, enable the RoleEntityACL component. Then restart.  This is assuming the other configuration settings have been made for the other ACLs in the earlier post.   Once enabled, a new metadata field called xClbraRoleList will be created.  If you are using OracleTextSearch as the search indexer, be sure to run a Fast Rebuild on the collection. For Users and Groups, these values are automatically picked up from the corresponding database tables.  In the case of Roles, there is an explicitly defined list of choices that are made available.  These values must match the roles that are coming from the enterprise security repository. To add these values, go to Administration -> Admin Applets -> Configuration Manager.  On the Views tab, edit the values for the ExternalRolesView.  By default, 'guest' and 'authenticated' are added.  Once added, you can assign the roles to your content or folder. If you are a user that can both access the Security Group for that item and you belong to that particular Role, you now have access to that item.  If you don't belong to that Role, you won't! [Extra] Because the selection mechanism for the list is using a type-ahead field, users may not even know the possible choices to start typing to.  To help them, one thing you can add to the form is a placeholder field which offers the entire list of roles as an option list they can scroll through (assuming its a manageable size)  and view to know what to type to.  By being a placeholder field, it won't need to be added to the custom metadata database table or search engine.  

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• Use a custom value object or a Guid as an entity identifier in a distributed system?

  - by Kazark

  tl;dr I've been told that in domain-driven design, an identifier for an entity could be a custom value object, i.e. something other than Guid, string, int, etc. Can this really be advisable in a distributed system? Long version I will invent an situation analogous to the one I am currently facing. Say I have a distributed system in which a central concept is an egg. The system allows you to order eggs and see spending reports and inventory-centric data such as quantity on hand, usage, valuation and what have you. There area variety of services backing these behaviors. And say there is also another app which allows you to compose recipes that link to a particular egg type. Now egg type is broken down by the species—ostrich, goose, duck, chicken, quail. This is fine and dandy because it means that users don't end up with ostrich eggs when they wanted quail eggs and whatnot. However, we've been getting complaints because jumbo chicken eggs are not even close to equivalent to small ones. The price is different, and they really aren't substitutable in recipes. And here we thought we were doing users a favor by not overwhelming them with too many options. Currently each of the services (say, OrderSubmitter, EggTypeDefiner, SpendingReportsGenerator, InventoryTracker, RecipeCreator, RecipeTracker, or whatever) are identifying egg types with an industry-standard integer representation the species (let's call it speciesCode). We realize we've goofed up because this change could effect every service. There are two basic proposed solutions: Use a predefined identifier type like Guid as the eggTypeID throughout all the services, but make EggTypeDefiner the only service that knows that this maps to a speciesCode and eggSizeCode (and potentially to an isOrganic flag in the future, or whatever). Use an EggTypeID value object which is a combination of speciesCode and eggSizeCode in every service. I've proposed the first solution because I'm hoping it better encapsulates the definition of what an egg type is in the EggTypeDefiner and will be more resilient to changes, say if some people now want to differentiate eggs by whether or not they are "organic". The second solution is being suggested by some people who understand DDD better than I do in the hopes that less enrichment and lookup will be necessary that way, with the justification that in DDD using a value object as an ID is fine. Also, they are saying that EggTypeDefiner is not a domain and EggType is not an entity and as such should not have a Guid for an ID. However, I'm not sure the second solution is viable. This "value object" is going to have to be serialized into JSON and URLs for GET requests and used with a variety of technologies (C#, JavaScript...) which breaks encapsulation and thus removes any behavior of the identifier value object (is either of the fields optional? etc.) Is this a case where we want to avoid something that would normally be fine in DDD because we are trying to do DDD in a distributed fashion? Summary Can it be a good idea to use a custom value object as an identifier in a distributed system (solution #2)?

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• Is Visual Source Safe (The latest Version) really that bad? Why? What's the Best Alternative? Why? [closed]

  - by hanzolo

  Over the years I've constantly heard horror stories, had people say "Real Programmers Dont Use VSS", and so on. BUT, then in the workplace I've worked at two companies, one, a very well known public facing high traffic website, and another high end Financial Services "Web-Based" hosted solution catering to some very large, very well known companies, which is where I currently Reside and everything's working just fine (KNOCK KNOCK!!). I'm constantly interfacing with EXTREMELY Old technology with some of these financial institutions.. OLD LIKE YOU WOULDN'T BELIEVE.. which leads me to the conclusion that if it works "LEAVE IT", and that maybe there's some value in old technology? at least enough value to overrule a rewrite!? right?? Is there something fundamentally flawed with the underlying technology that VSS uses? I have a feeling that if i said "someone said VSS Sucks" they would beg to differ, most likely give me this look like i dont know -ish, and I'd never gain back their respect and my credibility (well, that'll be hard to blow.. lol), BUT, give me an argument that I can take to someone whose been coding for 30 years, that builds Platforms that leverage current technology (.NET 3.5 / SQL 2008 R2 ), write's their own ORM with scaffolding and is able to provide a quality platform that supports thousands of concurrent users on a multi-tenant hosted solution, and does not agree with any benefits from having Source Control Integrated, and yet uses the Infamous Visual Source Safe. I have extensive experience with TFS up to 2010, and honestly I think it's great when a team (beyond developers) can embrace it. I've worked side by side with someone whose a die hard SVN'r and from a purist standpoint, I see the beauty in it (I need a bit more, out of my SS, but it surely suffices). So, why are such smarties not running away from Visual Source Safe? surely if it was so bad, it would've have been realized by now, and I would not be sitting here with this simple old, Check In, Check Out, Version Resistant, Label Intensive system. But here I am... I would love to drop an argument that would be the end all argument, but if it's a matter of opinion and personal experience, there seems to be too much leeway for keeping VSS. UPDATE: I guess the best case is to have the VSS supporters check other people's experiences and draw from that until we (please no) experience the breaking factor ourselves. Until then, i wont be engaging in a discussion to migrate off of VSS.. UPDATE 11-2012: So i was able to convince everyone at my work place that since MS is sun downing Visual Source Safe it might be time to migrate over to TFS. I was able to convince them and have recently upgraded our team to Visual Studio 2012 and TFS 2012. The migration was fairly painless, had to run analyze.exe which found a bunch of errors (not sure they'll ever affect the project) and then manually run the VSSConverter.exe. Again, painless, except it took 16 hours to migrate 5 years worth of everything.. and now we're on TFS.. much more integrated.. much more cooler.. so all in all, VSS served it's purpose for years without hick-up. There were no horror stories and Visual Source Save as source control worked just fine. so to all the nay sayers (me included). there's nothing wrong with using VSS. i wouldnt start a new project with it, and i would definitely consider migrating to TFS. (it's really not super difficult and a new "wizard" type converter is due out any day now so migrating should be painless). But from my experience, it worked just fine and got the job done.

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• Why is x=x++ undefined?

  - by ugoren

  It's undefined because the it modifies x twice between sequence points. The standard says it's undefined, therefore it's undefined. That much I know. But why? My understanding is that forbidding this allows compilers to optimize better. This could have made sense when C was invented, but now seems like a weak argument. If we were to reinvent C today, would we do it this way, or can it be done better? Or maybe there's a deeper problem, that makes it hard to define consistent rules for such expressions, so it's best to forbid them? So suppose we were to reinvent C today. I'd like to suggest simple rules for expressions such as x=x++, which seem to me to work better than the existing rules. I'd like to get your opinion on the suggested rules compared to the existing ones, or other suggestions. Suggested Rules: Between sequence points, order of evaluation is unspecified. Side effects take place immediately. There's no undefined behavior involved. Expressions evaluate to this value or that, but surely won't format your hard disk (strangely, I've never seen an implementation where x=x++ formats the hard disk). Example Expressions x=x++ - Well defined, doesn't change x. First, x is incremented (immediately when x++ is evaluated), then it's old value is stored in x. x++ + ++x - Increments x twice, evaluates to 2*x+2. Though either side may be evaluated first, the result is either x + (x+2) (left side first) or (x+1) + (x+1) (right side first). x = x + (x=3) - Unspecified, x set to either x+3 or 6. If the right side is evaluated first, it's x+3. It's also possible that x=3 is evaluated first, so it's 3+3. In either case, the x=3 assignment happens immediately when x=3 is evaluated, so the value stored is overwritten by the other assignment. x+=(x=3) - Well defined, sets x to 6. You could argue that this is just shorthand for the expression above. But I'd say that += must be executed after x=3, and not in two parts (read x, evaluate x=3, add and store new value). What's the Advantage? Some comments raised this good point. It's not that I'm after the pleasure of using x=x++ in my code. It's a strange and misleading expression. What I want is to be able to understand complicated expressions. Normally, a complicated expression is no more than the sum of its parts. If you understand the parts and the operators combining them, you can understand the whole. C's current behavior seems to deviate from this principle. One assignment plus another assignment suddenly doesn't make two assignments. Today, when I look at x=x++, I can't say what it does. With my suggested rules, I can, by simply examining its components and their relations.

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• MySQL Connector/Net 6.6.2 has been released

  - by fernando

  MySQL Connector/Net 6.6.2, a new version of the all-managed .NET driver for MySQL has been released.  This is the first of two beta releases intended to introduce users to the new features in the release.  This release is feature complete it should be stable enough for users to understand the new features and how we expect them to work.  As is the case with all non-GA releases, it should not be used in any production environment.  It is appropriate for use with MySQL server versions 5.0-5.6 It is now available in source and binary form from http://dev.mysql.com/downloads/connector/net/#downloads and mirror sites (note that not all mirror sites may be up to date at this point-if you can't find this version on some mirror, please try again later or choose another download site.) The 6.6 version of MySQL Connector/Net brings the following new features:   * Stored routine debugging   * Entity Framework 4.3 Code First support   * Pluggable authentication (now third parties can plug new authentications mechanisms into the driver).   * Full Visual Studio 2012 support: everything from Server Explorer to Intellisense & the Stored Routine debugger. Stored Procedure Debugging ------------------------------------------- We are very excited to introduce stored procedure debugging into our Visual Studio integration.  It works in a very intuitive manner by simply clicking 'Debug Routine' from Server Explorer. You can debug stored routines, functions & triggers. Some of the new features in this release include:   * Besides normal breakpoints, you can define conditional & pass count breakpoints.   * Now the debugger editor shows colorizing.   * Now you can change the values of locals in a function scope (previously caused deadlock due to functions executing within their own transaction).   * Now you can also debug triggers for 'replace' sql statements.   * In general anything related to locals, watches, breakpoints, stepping & call stack should work in a similar way to the C#'s Visual Studio debugger. Some limitations remains, due to the current debugger architecture:   * Some MySQL functions cannot be debugged currently (get_lock, release_lock, begin, commit, rollback, set transaction level)..   * Only one debug session may be active on a given server. The Debugger is feature complete at this point. We look forward to your feedback. Documentation ------------------------------------- The documentation is still being developed and will be readily available soon (before Beta 2).  You can view current Connector/Net documentation at http://dev.mysql.com/doc/refman/5.5/en/connector-net.html You can find our team blog at http://blogs.oracle.com/MySQLOnWindows. You can also post questions on our forums at http://forums.mysql.com/. Enjoy and thanks for the support! 

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• No access to Samba shares

  - by koanhead

  I have three shared folders in my local home directory- that is to say, on my Ubuntu desktop's /home/me/. All were set up using "Sharing Options" in Nautilus' right-click menu. The standard "Music" and "Videos" folders are configured identically: the "Guest Access" box is checked, but the "Allow others to create and delete" is not. The third folder, called "shared", is configured to not allow Guest access but to allow others to modify files. I have not altered /etc/samba/smb.conf by hand, I have only used Sharing Options to create and modify these so-called "shares". My roommates have two Windows 7 computers and one Ubuntu Netbook Remix netbook. I have the aforementioned desktop machine and laptop running 10.04. None of these machines can access any of the shares. Attempts to access the Guest shares result in the message \\machine\directory is not accessible. The network name could not be found. This is the error message generated by a VM running Windows 2000. The other Windows machines generate a similar error. The Ubuntu laptop gives the error Unable to mount location: Failed to mount Windows share. Hurrah, once again, for informative error messages. That really helps a lot. When attempting to browse the folder called "shared" from the laptop, I'm confronted with a password dialog. This behavior is the same will all machines I've tried in the situation. On entering my username and password for the account to which the shares belong, the password dialog briefly disappears and is replaced with an identical dialog. No error message, useful or not, appears. When attempting to browse this folder with the VM, the outcome is the same except that the password dialog helpfully states "incorrect username or password". My assumption is that the username and password in question is that of the user which owns the shares. I have tried all other username and password combinations available in this context and the outcome is the same. I would like to be able to share files. Sharing them with Windows machines is a nice feature, or would be if it was available. Really I consider sharing files between two machines with the same version of the same operating system kind of a minimum condition for network usability. Samba last functioned reliably for me more than ten years ago. I have attempted to use it on and off since then with only intermittent success. Oh, and "Personal File Sharing" from the Preferences menu does not result in an entry in Places → Network → my-server. In fact, the old entry "MY-SERVER" goes away and is replaced by "koanhead's public files on my-server", which when I attempt to open it from the laptop gives a "DBus.Error.NoReply: Message did not receive a reply." I know I come here and gripe about Ubuntu a lot, but on the other hand I spend literally hours every day trying to fix things in Ubuntu. It's a good system which aspires to greatness, which is why things like this either Need to work; or Be adequately documented. Ideally both would be the case. Anyway, rant over. Hopefully someone will have some insight on this issue. Thanks all who bother to read this wall o'text for your time.

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• MySQL, An Ideal Choice for The Cloud

  - by Bertrand Matthelié

  As the world's most popular web database, MySQL has quickly become the leading database for the cloud, with most providers offering MySQL-based services. Normal 0 false false false EN-US X-NONE X-NONE /* 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:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;} Access our Resource Kit to discover: Why MySQL has become the leading database in the cloud, and how it addresses the critical attributes of cloud-based deployments How ISVs rely on MySQL to power their SaaS offerings Best practices to deploy the world’s most popular open source database in public and private clouds Normal 0 false false false EN-US X-NONE X-NONE You will also find out how you can leverage MySQL together with Hadoop and other technologies to unlock the value of Big Data, either on-premise or in the cloud. Access white papers, webinars, case studies and other resources in /* 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:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;} our Resource Kit now!

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• DirectX particle system. ConstantBuffer

  - by Liuka

  I'm new in DirectX and I'm making a 2D game. I want to use a particle system to simulate a 3D starfield, so each star has to set its own constant buffer for the vertexshader es. to set it's world matrix. So if i have 500 stars (that move every frame) i need to call 500 times VSsetconstantbuffer, and map/unmap each buffer. with 500 stars i have an average of 220 fps and that's quite good. My bottelneck is Vs/PsSetconstantbuffer. If i dont call this function i have 400 fps(obliviously nothing is display, since i dont set the position of the stars). So is there a method to speed up the render of the particle system?? Ps. I'm using intel integrate graphic (hd 2000-3000). with a nvidia (or amd) gpu will i have the same bottleneck?? If, for example, i dont call setshaderresource i have 10-20 fps more (for 500 objcets), that is not 180.Why does SetConstantBuffer take so long?? LPVOID VSdataPtr = VSmappedResource.pData; memcpy(VSdataPtr, VSdata, CszVSdata); context->Unmap(VertexBuffer, 0); result = context->Map(PixelBuffer, 0, D3D11_MAP_WRITE_DISCARD, 0, &PSmappedResource); if (FAILED(result)) { outputResult.OutputErrorMessage(TITLE, L"Cannot map the PixelBuffer", &result, OUTPUT_ERROR_FILE); return; } LPVOID PSdataPtr = PSmappedResource.pData; memcpy(PSdataPtr, PSdata, CszPSdata); context->Unmap(PixelBuffer, 0); context->VSSetConstantBuffers(0, 1, &VertexBuffer); context->PSSetConstantBuffers(0, 1, &PixelBuffer); this update and set the buffer. It's part of the render method of a sprite class that contains a the vertex buffer and the texture to apply to the quads(it's a 2d game) too. I have an array of 500 stars (sprite setup with a star texture). Every frame: clear back buffer; draw the array of stars; present the backbuffer; draw also call the function update( which calculate the position of the sprite on screen based on a "camera class") Ok, create a vertex buffer with the vertices of each quads(stars) seems to be good, since the stars don't change their "virtual" position; so.... In a particle system (where particles move) it's better to have all the object in only one vertices array, rather then an array of different sprite/object in order to update all the vertices' position with a single setbuffer call. In this case i have to use a dynamic vertex buffer with the vertices positions like this: verticesForQuad={{ XMFLOAT3((float)halfDImensions.x-1+pos.x, (float)halfDImensions.y-1+pos.y, 1.0f), XMFLOAT2(1.0f, 0.0f) }, { XMFLOAT3((float)halfDImensions.x-1+pos.x, -(float)halfDImensions.y-1+pos.y, 1.0f), XMFLOAT2(1.0f, 1.0f) }, { XMFLOAT3(-(float)halfDImensions.x-1+pos.x, (float)halfDImensions.y-1.pos.y, 1.0f), XMFLOAT2(0.0f, 0.0f) }, { XMFLOAT3(-(float)halfDImensions.x-1.pos.x, -(float)halfDImensions.y-1+pos.y, 1.0f), XMFLOAT2(0.0f, 1.0f) }, ....other quads} where halfDimensions is the halfsize in pixel of a texture and pos the virtual position of a star. than create an array of verticesForQuad and create the vertex buffer ZeroMemory(&vertexDesc, sizeof(vertexDesc)); vertexDesc.Usage = D3D11_USAGE_DEFAULT; vertexDesc.BindFlags = D3D11_BIND_VERTEX_BUFFER; vertexDesc.ByteWidth = sizeof(VertexType)* 4*numStars; ZeroMemory(&resourceData, sizeof(resourceData)); resourceData.pSysMem = verticesForQuad; result = device->CreateBuffer(&vertexDesc, &resourceData, &CvertexBuffer); and call each frame Context->IASetVertexBuffers(0, 1, &CvertexBuffer, &stride, &offset); But if i want to add and remove obj i have to recreate the buffer each time, havent i?? There is a faster way? I think i can create a vertex buffer with a max size (es. 10000 objs) and when i update it set only the 250 position (for 250 onjs for example) and pass this number as the vertexCount to the draw function (numObjs*4), or i'm worng

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• Changing the Operating System with only Ubuntu installed

  - by Games Brainiac

  I really wanted to dive into the world of Open Source operating systems, so I downloaded the latest version of Ubuntu (13.10), and installed it on a clean(no operating system installed, absolutely nothing) Lenovo ThinkPad machine. After a few days, I wanted to try out a different Operating System (Elementary OS). I downloaded the ISO file, burned it to a USB, tested that the USB booted from a different computer (I have 2, one is the Lenovo, the other a HP). I was able to get the bootscreen, and everything worked like a charm after I set the BIOS to boot from USB Disk Drive instead of HD. After this, I went back to Lenovo, and tried to open up the boot menu, by pressing F12, so that I could load from a temporary device. To my surprise, nothing but the HD was listed. There was no Optical Drive, No USB Drive, absolutely nothing. So, I thought that these devices were probably disabled. So I went into my BIOS and checked to see what was the case. I saw that all my devices were enabled. USB and all the other devices such as network cable and the rest were all enabled. So, I thought this probably had something to do wit UEFI and Legacy Boot options. So, I made sure that both were enabled. This did not solve the problem either. Again, I got nothing but the option to boot from my Hard Disk. I thought the USB had to be at fault. I tried different ports, but to no avail. Next, I tried with a Live CD, which had Ubuntu on it. This failed too. I simply could not boot from anything other than my hard disk. Okay, so at this point, I was pretty desperate, so I installed Boot-Repair through: sudo add-apt-repository ppa:yannubuntu/boot-repair sudo apt-get update sudo apt-get install boot-repair What this did is lead me to GRUB. Ideally, its just a screen that gives me the option to load from Ubuntu or Advanced Settings. The Advanced settings had nothing but Ubuntu options in it. So, I kept on pressing ESC and that led me to the the grub console, and thats where I am right now with my Lenovo. I've also tried updating the BIOS, but Lenovo only has packages for Red Hat and Windows. So, a dead end there too. Right now, I need to know if there is any way that I can just delete everything from my Lenovo? I want to revert it back to its blank factory condition. How can I achieve this? I have tried to elaborate my problem as best I could. If there is any important information that I've missed out, please do not hesitate to leave a comment. I would have included some screen shots, but BIOS screen shots are a little hard to manage. However, I can provide a camera Image of the boot screen if needed (doing that as we speak).

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• On a BPM Mission with Process Accelerators. Part 1: BPM as an ATV

  - by Cesare Rotundo

  Normal 0 false false false EN-US X-NONE X-NONE /* 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-top:0in; mso-para-margin-right:0in; mso-para-margin-bottom:10.0pt; mso-para-margin-left:0in; line-height:115%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;} Part 1: BPM as an ATV It’s always exciting to talk to customers that are in the middle of a BPM transformational journey. Their thirst for new processes to improve with BPM makes them explorers in a landscape of opportunities. They have discovered that with BPM the can “go places” they couldn’t reach before. In a way, learning how to generate value with BPM is like adopting a new mean of transportation. Apps are like regular cars: very efficient, but to be used on paved roads: the road/process has been traced, and there are fixed paths to follow to get from “opportunity to quote” or from “quote to cash”. Getting off the road is risky, and laying down new asphalt is slow and expensive. Custom development is like running: you can go virtually anywhere, following any path you like, yet it’s slow, and a lot of sweat. BPM allows you to go “off the beaten path” laid out by packaged apps, yet make fast progress compared to custom development. BPM is therefore more like an All-Terrain Vehicle (ATV): less efficient than a car, but much faster than running, with a powerful enough engine that can get you places. The similarities between BPM and ATVs don’t stop here: you must learn to ride it even if you already know how to drive a car; you can reach places but figuring out the path to your destination is harder. Ultimately, with BPM as with an ATV, you reach places that you thought you could never reach, and you discover new destinations that provide great benefit to you … and that you didn’t even know existed! That’s where the sense of accomplishment that we heard from our BPM customers comes from, as well as the desire to share their experience, or even, as in the case of a County, the willingness to contribute their BPM solutions to help other agencies that face the same challenges. The question we wanted to answer is how can we teach organizations to drive ATV/BPM, thus leading them to deeper success with BPM, while increasing their awareness of the potential for reaching new targets, and finally equip them with the right tools. Like with ATVs, getting from point A to point B is more of a work of art than cruising on the highway by car. There is a lot we can do: after all many sought after destinations are common: someone else has been on the same path before. If only you could learn from their experience …

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• "The connection has timed out" - Please help!

  - by gon

  I recently installed a fresh Ubuntu 12.04 LTS on a desktop, and the installation itself was successful (other than 'grub rescue' issue that I encountered but fixed) but this connection problem is really giving me a headache. Symptoms: 1. When I open the FireFox browser and try to connect to a website, it just hangs for a while saying "Connecting..." but eventually loads an error page "The connection has timed out". 2. It's not a browser problem (and I tried setting ipv6 thing to "true" at about:config) because running "sudo apt-get install [some-random-package]" at terminal fails ("E: Unable to locate package [package]") too. All other operations that need internet access are not working. 3. I certainly see a wired network (called "eth1") at the Network Manager, and it says "Connection Established" after disconnecting and then connecting again. I have tried almost everything that could be found from google search results still no luck. Their problems slightly differ from mine or the solutions just don't work. By the way it didn't have internet access when installing Ubuntu 12.04. (I ignored the message that I need internet to install Ubuntu) Could this be a problem? I'm sorry I don't remember if internet worked or not on the previous version of Ubuntu. :( I would really appreciate your help... I don't even know what more to do if this fails too.. Thanks!! Thanks for your comment. Here is the result of ifconfig: eth0 Link encap:Ethernet HWaddr 78:ac:c0:3d:b2:b9 inet addr:10.10.65.185 Bcast:10.10.65.255 Mask:255.255.255.0 inet6 addr: fe80::7aac:c0ff:fe3d:b2b9/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:3907 errors:0 dropped:0 overruns:0 frame:0 TX packets:771 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:393118 (393.1 KB) TX bytes:73472 (73.4 KB) Interrupt:16 eth1 Link encap:Ethernet HWaddr 78:ac:c0:3d:b2:b8 UP BROADCAST MULTICAST MTU:1500 Metric:1 RX packets:0 errors:0 dropped:0 overruns:0 frame:0 TX packets:0 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:0 (0.0 B) TX bytes:0 (0.0 B) Interrupt:17 lo Link encap:Local Loopback inet addr:127.0.0.1 Mask:255.0.0.0 inet6 addr: ::1/128 Scope:Host UP LOOPBACK RUNNING MTU:16436 Metric:1 RX packets:4 errors:0 dropped:0 overruns:0 frame:0 TX packets:4 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 RX bytes:204 (204.0 B) TX bytes:204 (204.0 B) route -n: Kernel IP routing table Destination Gateway Genmask Flags Metric Ref Use Iface 0.0.0.0 10.10.65.1 0.0.0.0 UG 0 0 0 eth0 10.10.65.0 0.0.0.0 255.255.255.0 U 1 0 0 eth0 169.254.0.0 0.0.0.0 255.255.0.0 U 1000 0 0 eth0 /etc/resolv.conf: # Dynamic resolv.conf(5) file for glibc resolver(3) generated by resolvconf(8) # DO NOT EDIT THIS FILE BY HAND -- YOUR CHANGES WILL BE OVERWRITTEN nameserver 8.8.8.8 nameserver 8.8.4.4 nameserver 10.81.1.8 nameserver 10.1.2.10 nameserver 127.0.0.1 search yamatake.local /etc/network/interfaces: auto lo iface lo inet loopback #auto eth0 #iface eth0 inet dhcp #auto eth1 #iface eth1 inet dhcp And I'll also include the result of 'sudo lshw -C network' in case it might help: *-network description: Ethernet interface product: NetXtreme BCM5764M Gigabit Ethernet PCIe vendor: Broadcom Corporation physical id: 0 bus info: pci@0000:02:00.0 logical name: eth0 version: 10 serial: 78:ac:c0:3d:b2:b9 size: 100Mbit/s capacity: 1Gbit/s width: 64 bits clock: 33MHz capabilities: pm vpd msi pciexpress bus_master cap_list ethernet physical tp 10bt 10bt-fd 100bt 100bt-fd 1000bt 1000bt-fd autonegotiation configuration: autonegotiation=on broadcast=yes driver=tg3 driverversion=3.121 duplex=full firmware=5764m-v3.35 ip=10.10.65.185 latency=0 link=yes multicast=yes port=twisted pair speed=100Mbit/s resources: irq:93 memory:fc000000-fc00ffff *-network description: Ethernet interface product: NetXtreme BCM5764M Gigabit Ethernet PCIe vendor: Broadcom Corporation physical id: 0 bus info: pci@0000:01:00.0 logical name: eth1 version: 10 serial: 78:ac:c0:3d:b2:b8 size: 100Mbit/s capacity: 1Gbit/s width: 64 bits clock: 33MHz capabilities: pm vpd msi pciexpress bus_master cap_list ethernet physical tp 10bt 10bt-fd 100bt 100bt-fd 1000bt 1000bt-fd autonegotiation configuration: autonegotiation=on broadcast=yes driver=tg3 driverversion=3.121 duplex=full firmware=5764m-v3.35 latency=0 link=no multicast=yes port=twisted pair speed=100Mbit/s resources: irq:94 memory:fb000000-fb00ffff

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• Selective Suppression of Log Messages

  - by Duncan Mills

  Those of you who regularly read this blog will probably have noticed that I have a strange predilection for logging related topics, so why break this habit I ask?  Anyway here's an issue which came up recently that I thought was a good one to mention in a brief post.  The scenario really applies to production applications where you are seeing entries in the log files which are harmless, you know why they are there and are happy to ignore them, but at the same time you either can't or don't want to risk changing the deployed code to "fix" it to remove the underlying cause. (I'm not judging here). The good news is that the logging mechanism provides a filtering capability which can be applied to a particular logger to selectively "let a message through" or suppress it. This is the technique outlined below. First Create Your Filter  You create a logging filter by implementing the java.util.logging.Filter interface. This is a very simple interface and basically defines one method isLoggable() which simply has to return a boolean value. A return of false will suppress that particular log message and not pass it onto the handler. The method is passed the log record of type java.util.logging.LogRecord which provides you with access to everything you need to decide if you want to let this log message pass through or not, for example  getLoggerName(), getMessage() and so on. So an example implementation might look like this if we wanted to filter out all the log messages that start with the string "DEBUG" when the logging level is not set to FINEST:  public class MyLoggingFilter implements Filter {     public boolean isLoggable(LogRecord record) {         if ( !record.getLevel().equals(Level.FINEST) && record.getMessage().startsWith("DEBUG")){          return false;            }         return true;     } } Deploying   This code needs to be put into a JAR and added to your WebLogic classpath.  It's too late to load it as part of an application, so instead you need to put the JAR file into the WebLogic classpath using a mechanism such as the PRE_CLASSPATH setting in your domain setDomainEnv script. Then restart WLS of course. Using The final piece if to actually assign the filter.  The simplest way to do this is to add the filter attribute to the logger definition in the logging.xml file. For example, you may choose to define a logger for a specific class that is raising these messages and only apply the filter in that case.  <logger name="some.vendor.adf.ClassICantChange"         filter="oracle.demo.MyLoggingFilter"/> You can also apply the filter using WLST if you want a more script-y solution.

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• Criminals and Other Illegal Characters

  - by Most Valuable Yak (Rob Volk)

  SQLTeam's favorite Slovenian blogger Mladen (b | t) had an interesting question on Twitter: http://www.twitter.com/MladenPrajdic/status/347057950470307841 I liked Kendal Van Dyke's (b | t) reply: http://twitter.com/SQLDBA/status/347058908801667072 And he was right!  This is one of those pretty-useless-but-sounds-interesting propositions that I've based all my presentations on, and most of my blog posts. If you read all the replies you'll see a lot of good suggestions.  I particularly like Aaron Bertrand's (b | t) idea of going into the Unicode character set, since there are over 65,000 characters available.  But how to find an illegal character?  Detective work? I'm working on the premise that if SQL Server will reject it as a name it would throw an error.  So all we have to do is generate all Unicode characters, rename a database with that character, and catch any errors. It turns out that dynamic SQL can lend a hand here: IF DB_ID(N'a') IS NULL CREATE DATABASE [a]; DECLARE @c INT=1, @sql NVARCHAR(MAX)=N'', @err NVARCHAR(MAX)=N''; WHILE @c<65536 BEGIN BEGIN TRY SET @sql=N'alter database ' + QUOTENAME(CASE WHEN @c=1 THEN N'a' ELSE NCHAR(@c-1) END) + N' modify name=' + QUOTENAME(NCHAR(@c)); RAISERROR(N'*** Trying %d',10,1,@c) WITH NOWAIT; EXEC(@sql); SET @c+=1; END TRY BEGIN CATCH SET @err=ERROR_MESSAGE(); RAISERROR(N'Ooops - %d - %s',10,1,@c,@err) WITH NOWAIT; BREAK; END CATCH END SET @sql=N'alter database ' + QUOTENAME(NCHAR(@c-1)) + N' modify name=[a]'; EXEC(@sql); The script creates a dummy database "a" if it doesn't already exist, and only tests single characters as a database name.  If you have databases with single character names then you shouldn't run this on that server. It takes a few minutes to run, but if you do you'll see that no errors are thrown for any of the characters.  It seems that SQL Server will accept any character, no matter where they're from.  (Well, there's one, but I won't tell you which. Actually there's 2, but one of them requires some deep existential thinking.) The output is also interesting, as quite a few codes do some weird things there.  I'm pretty sure it's due to the font used in SSMS for the messages output window, not all characters are available.  If you run it using the SQLCMD utility, and use the -o switch to output to a file, and -u for Unicode output, you can open the file in Notepad or another text editor and see the whole thing. I'm not sure what character I'd recommend to answer Mladen's question.  I think the standard tab (ASCII 9) is fine.  There's also several specific separator characters in the original ASCII character set (decimal 28-31). But of all the choices available in Unicode whitespace, I think my favorite would be the Mongolian Vowel Separator.  Or maybe the zero-width space. (that'll be fun to print!)  And since this is Mladen we're talking about, here's a good selection of "intriguing" characters he could use.

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• Come up with a real-world problem in which only the best solution will do (a problem from Introduction to algorithms) [closed]

  - by Mike

  EDITED (I realized that the question certainly needs a context) The problem 1.1-5 in the book of Thomas Cormen et al Introduction to algorithms is: "Come up with a real-world problem in which only the best solution will do. Then come up with one in which a solution that is “approximately” the best is good enough." I'm interested in its first statement. And (from my understanding) it is asked to name a real-world problem where only the exact solution will work as opposed to a real-world problem where good-enough solution will be ok. So what is the difference between the exact and good enough solution. Consider some physics problem for example the simulation of the fulid flow in the permeable medium. To make this simulation happen some simplyfing assumptions have to be made when deriving a mathematical model. Otherwise the model becomes at least complex and unsolvable. Virtually any particle in the universe has its influence on the fluid flow. But not all particles are equal. Those that form the permeable medium are much more influental than the ones located light years away. Then when the mathematical model needs to be solved an exact solution can rarely be found unless the mathematical model is simple enough (wich probably means the model isn't close to reality). We take an approximate numerical method and after hours of coding and days of verification come up with the program or algorithm which is a solution. And if the model and an algorithm give results close to a real problem by some degree that is good enough soultion. Its worth noting the difference between exact solution algorithm and exact computation result. When considering real-world problems and real-world computation machines I believe all physical problems solutions where any calculations are taken can not be exact because universal physical constants are represented approximately in the computer. Any numbers are represented with the limited precision, at least limited by amount of memory available to computing machine. I can imagine plenty of problems where good-enough, good to some degree solution will work, like train scheduling, automated trading, satellite orbit calculation, health care expert systems. In that cases exact solutions can't be derived due to constraints on computation time, limitations in computer memory or due to the nature of problems. I googled this question and like what this guy suggests: there're kinds of mathematical problems that need exact solutions (little note here: because the question is taken from the book "Introduction to algorithms" the term "solution" means an algorithm or a program, which in this case gives exact answer on each input). But that's probably more of theoretical interest. So I would like to narrow down the question to: What are the real-world practical problems where only the best (exact) solution algorithm or program will do (but not the good-enough solution)? There are problems like breaking of cryptographic ciphers where only exact solution matters in practice and again in practice the process of deciphering without knowing a secret should take reasonable amount of time. Returning to the original question this is the problem where good-enough (fast-enough) solution will do there's no practical need in instant crack though it's desired. So the quality of "best" can be understood in any sense: exact, fastest, requiring least memory, having minimal possible network traffic etc. And still I want this question to be theoretical if possible. In a sense that there may be example of computer X that has limited resource R of amount Y where the best solution to problem P is the one that takes not more than available Y for inputs of size N*Y. But that's the problem of finding solution for P on computer X which is... well, good enough. My final thought that we live in a world where it is required from programming solutions to practical purposes to be good enough. In rare cases really very very good but still not the best ones. Isn't it? :) If it's not can you provide an example? Or can you name any such unsolved problem of practical interest?

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• ADF page security - the untold password rule

  - by ankuchak

  I'm kinda new to Oracle ADF. So, in this blog post I'm going to share something with you that I faced (and recovered from) recently. Initially I thought if I should at all put a blog post on this, because it's totally simple. Still, simplicity is a relative term. So without wasting further time, let's kick off.    I was exploring the ADF security aspect to secure a page through html basic authentication. The idea is very simple and the credential store etc. come into picture. But I was not able to run a successful test of this phenomenally simple thing even after trying for over 30 minutes. This is what I did.   I created a simple jsf page and put a panel in it. And I put a simple el to show the current user name.  Next I created a user that I should test with. I named the password as myuser, just to keep it simple. Then I created an enterprise role and mapped the user that I just created. Then I created an application role and mapped the enterprise role to it. Then I mapped the resource, the simple jsf page in this case, to this application role. This way, only users with the given application role can only access this page (as if you didn't know this duh!).  Of course, I had to create the page definition for the page before I could map it to an application role. What else! done! Then I hit the run menu item and it all went well...   Until... I got this message. I put the correct credentials repeatedly 2-3 times. Still I got the same error. Why? I didn't get any error message during the deployment. nope.  Then, as I said before, I spent over 30 minutes trying different things out, things like mapping only the user(not the role) to the page, changing the context root etc. Nothing worked!  Then of course, I bothered to look at the logs and found this. See the first red line. That says it all. So the problem was with that password. The password must have at least one special character and one digit in it. I think I was misled by the missing password hint/rule and the fact that the deployment didn't fail even if the user was not created properly. Well, yes, I agree that I was fool enough not to look at the logs.  Later I changed the password to something like myuser123# . And it worked. I hope it helped.

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• Rethinking Oracle Optimizer Statistics for P6 Part 2

  - by Brian Diehl

  In the previous post (Part 1), I tried to draw some key insights about the relationship between P6 and Oracle Optimizer Statistics.  The first is that average cardinality has the greatest impact on query optimization and that the particular queries generated by P6 are more likely to use this average during calculations. The second is that these are statistics that are unlikely to change greatly over the life of the application. Ultimately, our goal is to get the best query optimization possible.  Or is it? Stability No application administrator wants to get the call at 9am that their application users cannot get there work done because everything is running slow. This is a possibility with a regularly scheduled nightly collection of statistics. It may not just be slow performance, but a complete loss of service because one or more queries are optimized poorly. Ideally, this should not be the case. The database optimizer should make better decisions with more up-to-date data. Better statistics may give incremental performance benefit. However, this benefit must be balanced against the potential cost of system down time.  It is stability that we ultimately desire and not absolute optimal performance. We do want the benefit from more accurate statistics and better query plans, but not at the risk of an unusable system. As a result, I've developed the following methodology around managing database statistics for the P6 database.  1. No Automatic Re-Gathering - The daily, weekly, or other interval of statistic gathering is unlikely to be beneficial. Quite the opposite. It is more likely to cause problems. 2. Smart Re-Gathering - The time to collect statistics is when things have changed significantly. For a new installation of P6, this is happening more often because the data is growing from a few rows to thousands and more. But for a mature system, the data is not changing significantly from week-to-week. There are times to collect statistics: New releases of the application Changes in the underlying hardware or software versions (ex. new Oracle RDBMS version) When additional user groups are added. The new groups may use the software in significantly different ways. After significant changes in the data. This may be monthly, quarterly or yearly.  3. Always Test - If you take away one thing from this post, it would be to always have a plan to test after changing statistics. In reality, statistics can be collected as often as you desire provided there are tests in place to verify that performance is the same or better. These might be automated tests or simply a manual script of application functions. 4. Have a Way Out - Never change the statistics without a way to return to the previous set. Think of the statistics as one part of the overall application code that also includes the source code--both application and RDBMS. It would be foolish to change to the new code without a way to get back to the previous version. In the final post, I will talk about the actual script I created for P6 PMDB and possible future direction for managing query performance. 

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• glutPostRedisplay() does not update display

  - by A D

  I am currently drawing a rectangle to the screen and would like to move it by using the arrow keys. However, when I press an arrow key the vertex data changes but the display does refresh to reflect these changes, even though I am calling glutPostRedisplay(). Is there something else that I must do? My code: #include <GL/glew.h> #include <GL/freeglut.h> #include <GL/freeglut_ext.h> #include <iostream> #include "Shaders.h" using namespace std; const int NUM_VERTICES = 6; const GLfloat POS_Y = -0.1; const GLfloat NEG_Y = -0.01; struct Vertex { GLfloat x; GLfloat y; Vertex() : x(0), y(0) {} Vertex(GLfloat givenX, GLfloat givenY) : x(givenX), y(givenY) {} }; Vertex left_paddle[NUM_VERTICES]; void init() { glClearColor(1.0f, 1.0f, 1.0f, 0.0f); left_paddle[0] = Vertex(-0.95f, 0.95f); left_paddle[1] = Vertex(-0.95f, 0.0f); left_paddle[2] = Vertex(-0.85f, 0.95f); left_paddle[3] = Vertex(-0.85f, 0.95f); left_paddle[4] = Vertex(-0.95f, 0.0f); left_paddle[5] = Vertex(-0.85f, 0.0f); GLuint vao; glGenVertexArrays( 1, &vao ); glBindVertexArray( vao ); GLuint buffer; glGenBuffers(1, &buffer); glBindBuffer(GL_ARRAY_BUFFER, buffer); glBufferData(GL_ARRAY_BUFFER, sizeof(left_paddle), NULL, GL_STATIC_DRAW); GLuint program = init_shaders( "vshader.glsl", "fshader.glsl" ); glUseProgram( program ); GLuint loc = glGetAttribLocation( program, "vPosition" ); glEnableVertexAttribArray( loc ); glVertexAttribPointer( loc, 2, GL_FLOAT, GL_FALSE, 0, 0); glBindVertexArray(vao); } void movePaddle(Vertex* array, GLfloat change) { for(int i = 0; i < NUM_VERTICES; i++) { array[i].y = array[i].y + change; } glutPostRedisplay(); } void special( int key, int x, int y ) { switch ( key ) { case GLUT_KEY_DOWN: movePaddle(left_paddle, NEG_Y); break; } } void display() { glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); glDrawArrays(GL_TRIANGLES, 0, 6); glutSwapBuffers(); } int main(int argc, char **argv) { glutInit(&argc, argv); glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGB); glutInitWindowSize(500,500); glutCreateWindow("Rectangle"); glewInit(); init(); glutDisplayFunc(display); glutSpecialFunc(special); glutMainLoop(); return 0; }

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• Delegates: A Practical Understanding

  - by samerpaul

  It's been a while since I have written on this blog, and I'm planning on reviving it this summer, since I have more time to do so again.I've also recently started working on the iPhone platform, so I haven't been as busy in .NET as before.In either case, today's blog post applies to both C# and Objective-C, because it's more about a practical understanding of delegates than it is about code. When I was learning coding, I felt like delegates was one of the hardest things to conceptually understand, and a lot of books don't really do a good job (in my opinion) of explaining it. So here's my stab at it.A Real Life Example of DelegatesLet's say there are three of you. You, your friend, and your brother. You're each in a different room in your house so you can't hear each other, even if you shout. 1)You are playing a computer game2) Friend is building a puzzle3) Brother is nappingNow, you three are going to stay in your room but you want to be informed if anything interesting is happening to the one of you. Let's say you (playing the computer game) want to know when your brother wakes up.You could keep walking to the room, checking to see if he's napping, and then walking back to your room. But that would waste a lot of time / resources, and what if you miss when he's awake before he goes back to sleep? That would be bad.Instead, you hand him a 2-way radio that works between your room and his room. And you inform him that when he wakes up, he should press a button on the radio and say "I'm awake". You are going to be listening to that radio, waiting for him to say he's awake. This, in essence, is how a delegate works.You're creating an "object" (the radio) that allows you to listen in on an event you specify. You don't want him to send any other messages to you right now, except when he wakes up. And you want to know immediately when he does, so you can go over to his room and say hi. (the methods that are called when a delegate event fires). You're also currently specifying that only you are listening on his radio.Let's say you want your friend to come into the room at the same time as you, and do something else entirely, like fluff your brother's pillow. You will then give him an identical radio, that also hooks into your brother's radio, and inform him to wait and listen for the "i'm awake" signal.Then, when your brother wakes up, he says "I'm awake!" and both you and your friend walk into the room. You say hi, and your friend fluffs the pillow, then you both exit.Later, if you decide you don't care to say hi anymore, you turn off your radio. Now, you have no idea when your brother is awake or not, because you aren't listening anymore.So again, you are each classes in this example, and each of you have your own methods. You're playing a computer game (PlayComputerGame()), your friend is building a puzzle (BuildPuzzle()) and your brother is napping (Napping()). You create a delegate (ImAwake) that you set your brother to do, when he wakes up. You listen in on that delegate (giving yourself a radio and turning it on), and when you receive the message, you fire a new method called SayHi()). Your friend is also wired up to the same delegate (using an identical radio) and fires the method FluffPillow().Hopefully this makes sense, and helps shed some light on how delegates operate. Let me know! Feel free to drop me a line at Twitter (preferred method of contact) here: samerabousalbi

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• Webcast On-Demand: Building Java EE Apps That Scale

  - by jeckels

  With some awesome work by one of our architects, Randy Stafford, we recently completed a webcast on scaling Java EE apps efficiently. Did you miss it? No problem. We have a replay available on-demand for you. Just hit the '+' sign drop-down for access.Topics include: Domain object caching Service response caching Session state caching JSR-107 HotCache and more! Further, we had several interesting questions asked by our audience, and we thought we'd share a sampling of those here for you - just in case you had the same queries yourself. Enjoy! What is the largest Coherence deployment out there? We have seen deployments with over 500 JVMs in the Coherence cluster, and deployments with over 1000 JVMs using the Coherence jar file, in one system. On the management side there is an ecosystem of monitoring tools from Oracle and third parties with dashboards graphing values from Coherence's JMX instrumentation. For lifecycle management we have seen a lot of custom scripting over the years, but we've also integrated closely with WebLogic to leverage its management ecosystem for deploying Coherence-based applications and managing process life cycles. That integration introduces a new Java EE archive type, the Grid Archive or GAR, which embeds in an EAR and can be seen by a WAR in WebLogic. That integration also doesn't require any extra WebLogic licensing if Coherence is licensed. How is Coherence different from a NoSQL Database like MongoDB? Coherence can be considered a NoSQL technology. It pre-dates the NoSQL movement, having been first released in 2001 whereas the term "NoSQL" was coined in 2009. Coherence has a key-value data model primarily but can also be used for document data models. Coherence manages data in memory currently, though disk persistence is in a future release currently in beta testing. Where the data is managed yields a few differences from the most well-known NoSQL products: access latency is faster with Coherence, though well-known NoSQL databases can manage more data. Coherence also has features that well-known NoSQL database lack, such as grid computing, eventing, and data source integration. Finally Coherence has had 15 years of maturation and hardening from usage in mission-critical systems across a variety of industries, particularly financial services. Can I use Coherence for local caching? Yes, you get additional features beyond just a java.util.Map: you get expiration capabilities, size-limitation capabilities, eventing capabilites, etc. Are there APIs available for GoldenGate HotCache? It's mostly a black box. You configure it, and it just puts objects into your caches. However you can treat it as a glass box, and use Coherence event interceptors to enhance its behavior - and there are use cases for that. Are Coherence caches updated transactionally? Coherence provides several mechanisms for concurrency control. If a project insists on full-blown JTA / XA distributed transactions, Coherence caches can participate as resources. But nobody does that because it's a performance and scalability anti-pattern. At finer granularity, Coherence guarantees strict ordering of all operations (reads and writes) against a single cache key if the operations are done using Coherence's "EntryProcessor" feature. And Coherence has a unique feature called "partition-level transactions" which guarantees atomic writes of multiple cache entries (even in different caches) without requiring JTA / XA distributed transaction semantics.

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• No access to Samba shares

  - by koanhead

  I have three shared folders in my local home directory- that is to say, on my Ubuntu desktop's /home/me/. All were set up using "Sharing Options" in Nautilus' right-click menu. The standard "Music" and "Videos" folders are configured identically: the "Guest Access" box is checked, but the "Allow others to create and delete" is not. The third folder, called "shared", is configured to not allow Guest access but to allow others to modify files. I have not altered /etc/samba/smb.conf by hand, I have only used Sharing Options to create and modify these so-called "shares". My roommates have two Windows 7 computers and one Ubuntu Netbook Remix netbook. I have the aforementioned desktop machine and laptop running 10.04. None of these machines can access any of the shares. Attempts to access the Guest shares result in the message \\machine\directory is not accessible. The network name could not be found. This is the error message generated by a VM running Windows 2000. The other Windows machines generate a similar error. The Ubuntu laptop gives the error Unable to mount location: Failed to mount Windows share. Hurrah, once again, for informative error messages. That really helps a lot. When attempting to browse the folder called "shared" from the laptop, I'm confronted with a password dialog. This behavior is the same will all machines I've tried in the situation. On entering my username and password for the account to which the shares belong, the password dialog briefly disappears and is replaced with an identical dialog. No error message, useful or not, appears. When attempting to browse this folder with the VM, the outcome is the same except that the password dialog helpfully states "incorrect username or password". My assumption is that the username and password in question is that of the user which owns the shares. I have tried all other username and password combinations available in this context and the outcome is the same. I would like to be able to share files. Sharing them with Windows machines is a nice feature, or would be if it was available. Really I consider sharing files between two machines with the same version of the same operating system kind of a minimum condition for network usability. Samba last functioned reliably for me more than ten years ago. I have attempted to use it on and off since then with only intermittent success. Oh, and "Personal File Sharing" from the Preferences menu does not result in an entry in Places → Network → my-server. In fact, the old entry "MY-SERVER" goes away and is replaced by "koanhead's public files on my-server", which when I attempt to open it from the laptop gives a "DBus.Error.NoReply: Message did not receive a reply." I know I come here and gripe about Ubuntu a lot, but on the other hand I spend literally hours every day trying to fix things in Ubuntu. It's a good system which aspires to greatness, which is why things like this either Need to work; or Be adequately documented. Ideally both would be the case. Anyway, rant over. Hopefully someone will have some insight on this issue. Thanks all who bother to read this wall o'text for your time.

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• Is changing my job now a wise decision? [closed]

  - by FlaminPhoenix

  First a little background about myself. I am a javascript programmer with 3.8 years of experience. I joined my current company a year and 3 months ago, and I was recruited as a javascript programmer. I was under the impression I was a programmer in a programming team but this was not the case. No one else except me and my manager knows anything about programming in my team. The other two teammates, copy paste stuff from websites into excel sheets. I was told I was being recruited for a new project, and it was true. The only problem was that the server side language they were using was PHP. They were using a popular library with PHP, and I had never worked with PHP before. Nevertheless, I learnt it well enough to get things working, and received high praise from my boss's boss on whichever project I worked on. Words like "wow" , "This looks great, the clients gonna be impressed with this." were sprinkled every now and then on reviewing my work. They even managed to sell my work to a couple of clients and as I understand, both of my projects are going to fetch them a pretty buck. The problem: I was asked to move into a project which my manager was handling. I asked them for training on the project which never came, and sure enough I couldnt complete my first task on the new project without shortcomings. I told my manager there were things I didnt know how to get done in the new project due to lack of training. His project had 0 documentation. I was told he would "take care" of everything relating to those shortcomings. In the meantime, I was asked to switch to another project. My manager made the necessary changes and later told me that the build had "broken" on the production server and that I needed to "test" my changes before saying things were done. I never deployed it on the production server. He did. I never saw / had the opportunity to see the final build before it went to production. He called me for a separate meeting and started pointing fingers at me, but I took full responsibility even if I didnt have to. He later on got on a call with his boss, in my presence, and gave him the impression that it was all my fault. I did not confront him about this so far. I have worked late / done overtime without them asking a lot, but last week, I just got home from work, and I got calls asking me to solve an issue which till then they had kept quiet about even though they were informed about it. I asked my manager why I hadnt been tasked with this when I was in office. He started telling me which statements to put where, as if to mock me, and that this "is hardly an overtime issue" and this pissed me off. Also, during the previous meeting, he was constantly talking highly about his work, at the same time trying to demean mine. In the meantime, I have attended an interview with another MNC, and the interviewers there were fully respectful of my decision to leave my current company. Its a software company, so I can expect my colleagues to know a lot more than me. Im told I can expect their offer anytime this week. My questions: Is my anger towards my manager justified? While leaving, do I tell him that its because of his actions that Im leaving? Do I erupt in anger and tell him that he shouldnt have put the blame on me since he was the one doing the deployment? This is going to be my second resignation to this company. The first time I wanted to resign, I was asked to stay back and my manager promised a lot of changes, a couple of which were made. How do I keep myself from getting into such situations with my employers in the future?

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