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• Memory Efficient Windows SOA Server

  - by Antony Reynolds

  Installing a Memory Efficient SOA Suite 11.1.1.6 on Windows Server Well 11.1.1.6 is now available for download so I thought I would build a Windows Server environment to run it.  I will minimize the memory footprint of the installation by putting all functionality into the Admin Server of the SOA Suite domain. Required Software 64-bit JDK SOA Suite If you want 64-bit then choose “Generic” rather than “Microsoft Windows 32bit JVM” or “Linux 32bit JVM” This has links to all the required software. If you choose “Generic” then the Repository Creation Utility link does not show, you still need this so change the platform to “Microsoft Windows 32bit JVM” or “Linux 32bit JVM” to get the software. Similarly if you need a database then you need to change the platform to get the link to XE for Windows or Linux. If possible I recommend installing a 64-bit JDK as this allows you to assign more memory to individual JVMs. Windows XE will work, but it is better if you can use a full Oracle database because of the limitations on XE that sometimes cause it to run out of space with large or multiple SOA deployments. Installation Steps The following flow chart outlines the steps required in installing and configuring SOA Suite. The steps in the diagram are explained below. 64-bit? Is a 64-bit installation required?  The Windows & Linux installers will install 32-bit versions of the Sun JDK and JRockit.  A separate JDK must be installed for 64-bit. Install 64-bit JDK The 64-bit JDK can be either Hotspot or JRockit.  You can choose either JDK 1.7 or 1.6. Install WebLogic If you are using 64-bit then install WebLogic using “java –jar wls1036_generic.jar”.  Make sure you include Coherence in the installation, the easiest way to do this is to accept the “Typical” installation. SOA Suite Required? If you are not installing SOA Suite then you can jump straight ahead and create a WebLogic domain. Install SOA Suite Run the SOA Suite installer and point it at the existing Middleware Home created for WebLogic.  Note to run the SOA installer on Windows the user must have admin privileges.  I also found that on Windows Server 2008R2 I had to start the installer from a command prompt with administrative privileges, granting it privileges when it ran caused it to ignore the jreLoc parameter. Database Available? Do you have access to a database into which you can install the SOA schema.  SOA Suite requires access to an Oracle database (it is supported on other databases but I would always use an oracle database). Install Database I use an 11gR2 Oracle database to avoid XE limitations.  Make sure that you set the database character set to be unicode (AL32UTF8).  I also disabled the new security settings because they get in the way for a developer database.  Don’t forget to check that number of processes is at least 150 and number of sessions is not set, or is set to at least 200 (in the DB init parameters). Run RCU The SOA Suite database schemas are created by running the Repository Creation Utility.  Install the “SOA and BPM Infrastructure” component to support SOA Suite.  If you keep the schema prefix as “DEV” then the config wizard is easier to complete. Run Config Wizard The Config wizard creates the domain which hosts the WebLogic server instances.  To get a minimum footprint SOA installation choose the “Oracle Enterprise Manager” and “Oracle SOA Suite for developers” products.  All other required products will be automatically selected. The “for developers” installs target the appropriate components at the AdminServer rather than creating a separate managed server to house them.  This reduces the number of JVMs required to run the system and hence the amount of memory required.  This is not suitable for anything other than a developer environment as it mixes the admin and runtime functions together in a single server.  It also takes a long time to load all the required modules, making start up a slow process. If it exists I would recommend running the config wizard found in the “oracle_common/common/bin” directory under the middleware home.  This should have access to all the templates, including SOA. If you also want to run BAM in the same JVM as everything else then you need to “Select Optional Configuration” for “Managed Servers, Clusters and Machines”. To target BAM at the AdminServer delete the “bam_server1” managed server that is created by default.  This will result in BAM being targeted at the AdminServer. Installation Issues I had a few problems when I came to test everything in my mega-JVM. Following applications were not targeted and so I needed to target them at the AdminServer: b2bui composer Healthcare UI FMW Welcome Page Application (11.1.0.0.0) How Memory Efficient is It? On a Windows 2008R2 Server running under VirtualBox I was able to bring up both the 11gR2 database and SOA/BPM/BAM in 3G memory.  I allocated a minimum 512M to the PermGen and a minimum of 1.5G for the heap.  The setting from setSOADomainEnv are shown below: set DEFAULT_MEM_ARGS=-Xms1536m -Xmx2048m set PORT_MEM_ARGS=-Xms1536m -Xmx2048m set DEFAULT_MEM_ARGS=%DEFAULT_MEM_ARGS% -XX:PermSize=512m -XX:MaxPermSize=768m set PORT_MEM_ARGS=%PORT_MEM_ARGS% -XX:PermSize=512m -XX:MaxPermSize=768m I arrived at these numbers by monitoring JVM memory usage in JConsole. Task Manager showed total system memory usage at 2.9G – just below the 3G I allocated to the VM. Performance is not stellar but it runs and I could run JDeveloper alongside it on my 8G laptop, so in that sense it was a result!

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• Querying Visual Studio project files using T-SQL and Powershell

  - by jamiet

  Earlier today I had a need to get some information out of a Visual Studio project file and in this blog post I’m going to share a couple of ways of going about that because I’m pretty sure I won’t be the only person that ever wants to do this. The specific problem I was trying to solve was finding out how many objects in my database project (i.e. in my .dbproj file) had any warnings suppressed but the techniques discussed below will work pretty well for any Visual Studio project file because every such file is simply an XML document, hence it can be queried by anything that can query XML documents. Ever heard the phrase “when all you’ve got is hammer everything looks like a nail”? Well that’s me with querying stuff – if I can write SQL then I’m writing SQL. Here’s a little noddy database project I put together for demo purposes: Two views and a stored procedure, nothing fancy. I suppressed warnings for [View1] & [Procedure1] and hence the pertinent part my project file looks like this:   <ItemGroup>    <Build Include="Schema Objects\Schemas\dbo\Views\View1.view.sql">      <SubType>Code</SubType>      <SuppressWarnings>4151,3276</SuppressWarnings>    </Build>    <Build Include="Schema Objects\Schemas\dbo\Views\View2.view.sql">      <SubType>Code</SubType>    </Build>    <Build Include="Schema Objects\Schemas\dbo\Programmability\Stored Procedures\Procedure1.proc.sql">      <SubType>Code</SubType>      <SuppressWarnings>4151</SuppressWarnings>    </Build>  </ItemGroup>  <ItemGroup> Note the <SuppressWarnings> elements – those are the bits of information that I am after. With a lot of help from folks on the SQL Server XML forum  I came up with the following query that nailed what I was after. It reads the contents of the .dbproj file into a variable of type XML and then shreds it using T-SQL’s XML data type methods: DECLARE @xml XML; SELECT @xml = CAST(pkgblob.BulkColumn AS XML) FROM   OPENROWSET(BULK 'C:\temp\QueryingProjectFileDemo\QueryingProjectFileDemo.dbproj' -- <-Change this path!                    ,single_blob) AS pkgblob                    ;WITH XMLNAMESPACES( 'http://schemas.microsoft.com/developer/msbuild/2003' AS ns) SELECT  REVERSE(SUBSTRING(REVERSE(ObjectPath),0,CHARINDEX('\',REVERSE(ObjectPath)))) AS [ObjectName]        ,[SuppressedWarnings] FROM   (        SELECT  build.query('.') AS [_node]        ,       build.value('ns:SuppressWarnings[1]','nvarchar(100)') AS [SuppressedWarnings]        ,       build.value('@Include','nvarchar(1000)') AS [ObjectPath]        FROM    @xml.nodes('//ns:Build[ns:SuppressWarnings]') AS R(build)        )q And here’s the output: And that’s it – an easy way of discovering which warnings have been suppressed and for which objects in your database projects. I won’t bother going over the code as it is fairly self-explanatory – peruse it at your leisure.   Once I had the SQL above I figured I’d share it around a little in case it was ever useful to anyone else; hence I’m writing this blog post and I also posted it on the Visual Studio Database Development Tools forum at FYI: Discover which objects have had warnings suppressed. Luckily Kevin Goode saw the thread and he posted a different solution to the same problem, one that uses Powershell. The advantage of Kevin’s Powershell approach is that it is easy to analyse many .dbproj files at the same time. Below is Kevin’s code which I have tweaked ever so slightly so that it produces the same results as my SQL script (I just want any object that had had a warning suppressed whereas Kevin was querying specifically for warning 4151):   cd 'C:\Temp\QueryingProjectFileDemo\' cls $projects = ls -r -i *.dbproj Foreach($project in $projects) { $xml = new-object System.Xml.XmlDocument $xml.set_PreserveWhiteSpace( $true ) $xml.Load($project) #$xpath = @{Start="/e:Project/e:ItemGroup/e:Build[e:SuppressWarnings=4151]/@Include"} #$xpath = @{Start="/e:Project/e:ItemGroup/e:Build[contains(e:SuppressWarnings,'4151')]/@Include"} $xpath = @{Start="/e:Project/e:ItemGroup/e:Build[e:SuppressWarnings]/@Include"} $ns = @{ e = "http://schemas.microsoft.com/developer/msbuild/2003" } $xml | Select-Xml -XPath $xpath.Start -Namespace $ns |Select -Expand Node | Select -expand Value } and here’s the output: Nice reusable Powershell and SQL scripts – not bad for an evening’s work. Thank you to Kevin for allowing me to share his code. Don’t forget that these techniques can easily be adapted to query any Visual Studio project file, they’re only XML documents after all! Doubtless many people out there already have code for doing this but nonetheless here is another offering to the great script library in the sky. Have fun! @Jamiet

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• Tip: Replacing Html.Encode Calls With New Html Encoding Syntax

  Like the well disciplined secure developer that you are, when you built your ASP.NET MVC 1.0 application, you remembered to call Html.Encode every time you output a value that came from user input. Didnt you? Well, in ASP.NET MVC 2 running on ASP.NET 4, those calls can be replaced with the new HTML encoding syntax (aka code nugget). Ive written a three part series on the topic. Html Encoding Code Blocks With ASP.NET 4 Html Encoding Nuggets With ASP.NET MVC 2 Using AntiXss as the default...Did you know that DotNetSlackers also publishes .net articles written by top known .net Authors? We already have over 80 articles in several categories including Silverlight. Take a look: here.

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• Thread placement policies on NUMA systems - update

  - by Dave

  In a prior blog entry I noted that Solaris used a "maximum dispersal" placement policy to assign nascent threads to their initial processors. The general idea is that threads should be placed as far away from each other as possible in the resource topology in order to reduce resource contention between concurrently running threads. This policy assumes that resource contention -- pipelines, memory channel contention, destructive interference in the shared caches, etc -- will likely outweigh (a) any potential communication benefits we might achieve by packing our threads more densely onto a subset of the NUMA nodes, and (b) benefits of NUMA affinity between memory allocated by one thread and accessed by other threads. We want our threads spread widely over the system and not packed together. Conceptually, when placing a new thread, the kernel picks the least loaded node NUMA node (the node with lowest aggregate load average), and then the least loaded core on that node, etc. Furthermore, the kernel places threads onto resources -- sockets, cores, pipelines, etc -- without regard to the thread's process membership. That is, initial placement is process-agnostic. Keep reading, though. This description is incorrect. On Solaris 10 on a SPARC T5440 with 4 x T2+ NUMA nodes, if the system is otherwise unloaded and we launch a process that creates 20 compute-bound concurrent threads, then typically we'll see a perfect balance with 5 threads on each node. We see similar behavior on an 8-node x86 x4800 system, where each node has 8 cores and each core is 2-way hyperthreaded. So far so good; this behavior seems in agreement with the policy I described in the 1st paragraph. I recently tried the same experiment on a 4-node T4-4 running Solaris 11. Both the T5440 and T4-4 are 4-node systems that expose 256 logical thread contexts. To my surprise, all 20 threads were placed onto just one NUMA node while the other 3 nodes remained completely idle. I checked the usual suspects such as processor sets inadvertently left around by colleagues, processors left offline, and power management policies, but the system was configured normally. I then launched multiple concurrent instances of the process, and, interestingly, all the threads from the 1st process landed on one node, all the threads from the 2nd process landed on another node, and so on. This happened even if I interleaved thread creating between the processes, so I was relatively sure the effect didn't related to thread creation time, but rather that placement was a function of process membership. I this point I consulted the Solaris sources and talked with folks in the Solaris group. The new Solaris 11 behavior is intentional. The kernel is no longer using a simple maximum dispersal policy, and thread placement is process membership-aware. Now, even if other nodes are completely unloaded, the kernel will still try to pack new threads onto the home lgroup (socket) of the primordial thread until the load average of that node reaches 50%, after which it will pick the next least loaded node as the process's new favorite node for placement. On the T4-4 we have 64 logical thread contexts (strands) per socket (lgroup), so if we launch 48 concurrent threads we will find 32 placed on one node and 16 on some other node. If we launch 64 threads we'll find 32 and 32. That means we can end up with our threads clustered on a small subset of the nodes in a way that's quite different that what we've seen on Solaris 10. So we have a policy that allows process-aware packing but reverts to spreading threads onto other nodes if a node becomes too saturated. It turns out this policy was enabled in Solaris 10, but certain bugs suppressed the mixed packing/spreading behavior. There are configuration variables in /etc/system that allow us to dial the affinity between nascent threads and their primordial thread up and down: see lgrp_expand_proc_thresh, specifically. In the OpenSolaris source code the key routine is mpo_update_tunables(). This method reads the /etc/system variables and sets up some global variables that will subsequently be used by the dispatcher, which calls lgrp_choose() in lgrp.c to place nascent threads. Lgrp_expand_proc_thresh controls how loaded an lgroup must be before we'll consider homing a process's threads to another lgroup. Tune this value lower to have it spread your process's threads out more. To recap, the 'new' policy is as follows. Threads from the same process are packed onto a subset of the strands of a socket (50% for T-series). Once that socket reaches the 50% threshold the kernel then picks another preferred socket for that process. Threads from unrelated processes are spread across sockets. More precisely, different processes may have different preferred sockets (lgroups). Beware that I've simplified and elided details for the purposes of explication. The truth is in the code. Remarks: It's worth noting that initial thread placement is just that. If there's a gross imbalance between the load on different nodes then the kernel will migrate threads to achieve a better and more even distribution over the set of available nodes. Once a thread runs and gains some affinity for a node, however, it becomes "stickier" under the assumption that the thread has residual cache residency on that node, and that memory allocated by that thread resides on that node given the default "first-touch" page-level NUMA allocation policy. Exactly how the various policies interact and which have precedence under what circumstances could the topic of a future blog entry. The scheduler is work-conserving. The x4800 mentioned above is an interesting system. Each of the 8 sockets houses an Intel 7500-series processor. Each processor has 3 coherent QPI links and the system is arranged as a glueless 8-socket twisted ladder "mobius" topology. Nodes are either 1 or 2 hops distant over the QPI links. As an aside the mapping of logical CPUIDs to physical resources is rather interesting on Solaris/x4800. On SPARC/Solaris the CPUID layout is strictly geographic, with the highest order bits identifying the socket, the next lower bits identifying the core within that socket, following by the pipeline (if present) and finally the logical thread context ("strand") on the core. But on Solaris on the x4800 the CPUID layout is as follows. [6:6] identifies the hyperthread on a core; bits [5:3] identify the socket, or package in Intel terminology; bits [2:0] identify the core within a socket. Such low-level details should be of interest only if you're binding threads -- a bad idea, the kernel typically handles placement best -- or if you're writing NUMA-aware code that's aware of the ambient placement and makes decisions accordingly. Solaris introduced the so-called critical-threads mechanism, which is expressed by putting a thread into the FX scheduling class at priority 60. The critical-threads mechanism applies to placement on cores, not on sockets, however. That is, it's an intra-socket policy, not an inter-socket policy. Solaris 11 introduces the Power Aware Dispatcher (PAD) which packs threads instead of spreading them out in an attempt to be able to keep sockets or cores at lower power levels. Maximum dispersal may be good for performance but is anathema to power management. PAD is off by default, but power management polices constitute yet another confounding factor with respect to scheduling and dispatching. If your threads communicate heavily -- one thread reads cache lines last written by some other thread -- then the new dense packing policy may improve performance by reducing traffic on the coherent interconnect. On the other hand if your threads in your process communicate rarely, then it's possible the new packing policy might result on contention on shared computing resources. Unfortunately there's no simple litmus test that says whether packing or spreading is optimal in a given situation. The answer varies by system load, application, number of threads, and platform hardware characteristics. Currently we don't have the necessary tools and sensoria to decide at runtime, so we're reduced to an empirical approach where we run trials and try to decide on a placement policy. The situation is quite frustrating. Relatedly, it's often hard to determine just the right level of concurrency to optimize throughput. (Understanding constructive vs destructive interference in the shared caches would be a good start. We could augment the lines with a small tag field indicating which strand last installed or accessed a line. Given that, we could augment the CPU with performance counters for misses where a thread evicts a line it installed vs misses where a thread displaces a line installed by some other thread.)

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• Nagy dobás készül az Oracle adatányászati felületen, Oracle Data Mining

  - by Fekete Zoltán

  Ahogyan már a tavaly oszi Oracle OpenWorld hírekben és eloadásokban is láthattuk a beharangozót, az Oracle nagy dobásra készül az adatbányászati fronton (Oracle Data Mining), mégpedig a remekül használható adatbányászati motor grafikus felületének a kiterjesztésével. Ha jól megfigyeljük ezt az utóbbi linket, az eddigi grafikus felület már Oracle Data Miner Classic néven fut. Hogyan is lehet használni az Oracle Data Mining-ot? - Oracle Data Miner (ingyenesen letöltheto GUI az OTN-rol) - Java-ból és PL/SQL-bol, Oracle Data Mining JDeveloper and SQL Developer Extensions - Excel felületrol, Oracle Spreadsheet Add-In for Predictive Analytics - ODM Connector for mySAP BW Oracle Data Mining technikai információ.

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• Iron Speed Designer Review

  While Visual Studio allows developers to get productive fast by providing great design tools for a UI, it still lacks the ability to do smart layouts, data connections and queries. It is in this area that RAD suite of applications can tremendously boost productivity by abstracting away some of these issues and saving developer time to focus on business intelligence instead of data extraction and presentation. When it comes to RAD application suites for managed web applications, there is non better than Iron Speed Designer. The ease with which you can create a data-centric web application and have different reports of your data within minutes are unparalleled. This review delves into what Iron Speed Designer has to offer as well as some of its limitations. Iron Speed works with .NET 2.0, 3.0, 3.5 and even the latest version .NET 4.0. Read More >

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• WIF

  - by kaleidoscope

  Windows Identity Foundation (WIF) enables .NET developers to externalize identity logic from their application, improving developer productivity, enhancing application security, and enabling interoperability. It is a framework for implementing claims-based identity in your applications. With WIF one can create more secure applications by reducing custom implementations and using a single simplified identity model based on claims. Windows Identity Foundation is part of Microsoft's identity and access management solution built on Active Directory that also includes: · Active Directory Federation Services 2.0 (formerly known as "Geneva" Server): a security token service for IT that issues and transforms claims and other tokens, manages user access and enables federation and access management for simplified single sign-on · Windows CardSpace 2.0 (formerly known as Windows CardSpace "Geneva"): for helping users navigate access decisions and developers to build customer authentication experiences for users. Reference : http://msdn.microsoft.com/en-us/security/aa570351.aspx Geeta

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• Windows Azure Recipe: Software as a Service (SaaS)

  - by Clint Edmonson

  The cloud was tailor built for aspiring companies to create innovative internet based applications and solutions. Whether you’re a garage startup with very little capital or a Fortune 1000 company, the ability to quickly setup, deliver, and iterate on new products is key to capturing market and mind share. And if you can capture that share and go viral, having resiliency and infinite scale at your finger tips is great peace of mind. Drivers Cost avoidance Time to market Scalability Solution Here’s a sketch of how a basic Software as a Service solution might be built out: Ingredients Web Role – this hosts the core web application. Each web role will host an instance of the software and as the user base grows, additional roles can be spun up to meet demand. Access Control – this service is essential to managing user identity. It’s backed by a full blown implementation of Active Directory and allows the definition and management of users, groups, and roles. A pre-built ASP.NET membership provider is included in the training kit to leverage this capability but it’s also flexible enough to be combined with external Identity providers including Windows LiveID, Google, Yahoo!, and Facebook. The provider model provides extensibility to hook into other industry specific identity providers as well. Databases – nearly every modern SaaS application is backed by a relational database for its core operational data. If the solution is sold to organizations, there’s a good chance multi-tenancy will be needed. An emerging best practice for SaaS applications is to stand up separate SQL Azure database instances for each tenant’s proprietary data to ensure isolation from other tenants. Worker Role – this is the best place to handle autonomous background processing such as data aggregation, billing through external services, and other specialized tasks that can be performed asynchronously. Placing these tasks in a worker role frees the web roles to focus completely on user interaction and data input and provides finer grained control over the system’s scalability and throughput. Caching (optional) – as a web site traffic grows caching can be leveraged to keep frequently used read-only, user specific, and application resource data in a high-speed distributed in-memory for faster response times and ultimately higher scalability without spinning up more web and worker roles. It includes a token based security model that works alongside the Access Control service. Blobs (optional) – depending on the nature of the software, users may be creating or uploading large volumes of heterogeneous data such as documents or rich media. Blob storage provides a scalable, resilient way to store terabytes of user data. The storage facilities can also integrate with the Access Control service to ensure users’ data is delivered securely. Training & Examples These links point to online Windows Azure training labs and examples where you can learn more about the individual ingredients described above. (Note: The entire Windows Azure Training Kit can also be downloaded for offline use.) Windows Azure (16 labs) Windows Azure is an internet-scale cloud computing and services platform hosted in Microsoft data centers, which provides an operating system and a set of developer services which can be used individually or together. It gives developers the choice to build web applications; applications running on connected devices, PCs, or servers; or hybrid solutions offering the best of both worlds. New or enhanced applications can be built using existing skills with the Visual Studio development environment and the .NET Framework. With its standards-based and interoperable approach, the services platform supports multiple internet protocols, including HTTP, REST, SOAP, and plain XML SQL Azure (7 labs) Microsoft SQL Azure delivers on the Microsoft Data Platform vision of extending the SQL Server capabilities to the cloud as web-based services, enabling you to store structured, semi-structured, and unstructured data. Windows Azure Services (9 labs) As applications collaborate across organizational boundaries, ensuring secure transactions across disparate security domains is crucial but difficult to implement. Windows Azure Services provides hosted authentication and access control using powerful, secure, standards-based infrastructure. Developing Applications for the Cloud, 2nd Edition (eBook) This book demonstrates how you can create from scratch a multi-tenant, Software as a Service (SaaS) application to run in the cloud using the latest versions of the Windows Azure Platform and tools. The book is intended for any architect, developer, or information technology (IT) professional who designs, builds, or operates applications and services that run on or interact with the cloud. Fabrikam Shipping (SaaS reference application) This is a full end to end sample scenario which demonstrates how to use the Windows Azure platform for exposing an application as a service. We developed this demo just as you would: we had an existing on-premises sample, Fabrikam Shipping, and we wanted to see what it would take to transform it in a full subscription based solution. The demo you find here is the result of that investigation See my Windows Azure Resource Guide for more guidance on how to get started, including more links web portals, training kits, samples, and blogs related to Windows Azure.

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• LINQ und ArcObjects

  - by Marko Apfel

  LINQ und ArcObjects Motivation LINQ1 (language integrated query) ist eine Komponente des Microsoft .NET Frameworks seit der Version 3.5. Es erlaubt eine SQL-ähnliche Abfrage zu verschiedenen Datenquellen wie SQL, XML u.v.m. Wie SQL auch, bietet LINQ dazu eine deklarative Notation der Problemlösung - d.h. man muss nicht im Detail beschreiben wie eine Aufgabe, sondern was überhaupt zu lösen ist. Das befreit den Entwickler abfrageseitig von fehleranfälligen Iterator-Konstrukten. Ideal wäre es natürlich auf diese Möglichkeiten auch in der ArcObjects-Programmierung mit Features zugreifen zu können. Denkbar wäre dann folgendes Konstrukt: var largeFeatures = from feature in features where (feature.GetValue("SHAPE_Area").ToDouble() > 3000) select feature; bzw. dessen Äquivalent als Lambda-Expression: var largeFeatures = features.Where(feature => (feature.GetValue("SHAPE_Area").ToDouble() > 3000)); Dazu muss ein entsprechender Provider zu Verfügung stehen, der die entsprechende Iterator-Logik managt. Dies ist leichter als man auf den ersten Blick denkt - man muss nur die gewünschten Entitäten als IEnumerable<IFeature> liefern. (Anm.: nicht wundern - die Methoden GetValue() und ToDouble() habe ich nebenbei als Erweiterungsmethoden deklariert.) Im Hintergrund baut LINQ selbständig eine Zustandsmaschine (state machine)2 auf deren Ausführung verzögert ist (deferred execution)3 - d.h. dass erst beim tatsächlichen Anfordern von Entitäten (foreach, Count(), ToList(), ..) eine Instanziierung und Verarbeitung stattfindet, obwohl die Zuweisung schon an ganz anderer Stelle erfolgte. Insbesondere bei mehrfacher Iteration durch die Entitäten reibt man sich bei den ersten Debuggings verwundert die Augen wenn der Ausführungszeiger wie von Geisterhand wieder in die Iterator-Logik springt. Realisierung Eine ganz knappe Logik zum Konstruieren von IEnumerable<IFeature> lässt sich mittels Durchlaufen eines IFeatureCursor realisieren. Dazu werden die einzelnen Feature mit yield ausgegeben. Der einfachen Verwendung wegen, habe ich die Logik in eine Erweiterungsmethode GetFeatures() für IFeatureClass aufgenommen: public static IEnumerable GetFeatures(this IFeatureClass featureClass, IQueryFilter queryFilter, RecyclingPolicy policy) { IFeatureCursor featureCursor = featureClass.Search(queryFilter, RecyclingPolicy.Recycle == policy); IFeature feature; while (null != (feature = featureCursor.NextFeature())) { yield return feature; } //this is skipped in unit tests with cursor-mock if (Marshal.IsComObject(featureCursor)) { Marshal.ReleaseComObject(featureCursor); } } Damit kann man sich nun ganz einfach die IEnumerable<IFeature> erzeugen lassen: IEnumerable features = _featureClass.GetFeatures(RecyclingPolicy.DoNotRecycle); Etwas aufpassen muss man bei der Verwendung des "Recycling-Cursors". Nach einer verzögerten Ausführung darf im selben Kontext nicht erneut über die Features iteriert werden. In diesem Fall wird nämlich nur noch der Inhalt des letzten (recycelten) Features geliefert und alle Features sind innerhalb der Menge gleich. Kritisch würde daher das Konstrukt largeFeatures.ToList(). ForEach(feature => Debug.WriteLine(feature.OID)); weil ToList() schon einmal durch die Liste iteriert und der Cursor somit einmal durch die Features bewegt wurde. Die Erweiterungsmethode ForEach liefert dann immer dasselbe Feature. In derartigen Situationen darf also kein Cursor mit Recycling verwendet werden. Ein mehrfaches Ausführen von foreach ist hingegen kein Problem weil dafür jedes Mal die Zustandsmaschine neu instanziiert wird und somit der Cursor neu durchlaufen wird – das ist die oben schon erwähnte Magie. Ausblick Nun kann man auch einen Schritt weiter gehen und ganz eigene Implementierungen für die Schnittstelle IEnumerable<IFeature> in Angriff nehmen. Dazu müssen nur die Methode und das Property zum Zugriff auf den Enumerator ausprogrammiert werden. Im Enumerator selbst veranlasst man in der Reset()-Methode das erneute Ausführen der Suche – dazu übergibt man beispielsweise ein entsprechendes Delegate in den Konstruktur: new FeatureEnumerator( _featureClass, featureClass => featureClass.Search(_filter, isRecyclingCursor)); und ruft dieses beim Reset auf: public void Reset() {     _featureCursor = _resetCursor(_t); } Auf diese Art und Weise können Enumeratoren für völlig verschiedene Szenarien implementiert werden, die clientseitig restlos identisch nach obigen Schema verwendet werden. Damit verschmelzen Cursors, SelectionSets u.s.w. zu einer einzigen Materie und die Wiederverwendbarkeit von Code steigt immens. Obendrein lässt sich ein IEnumerable in automatisierten Unit-Tests sehr einfach mocken - ein großer Schritt in Richtung höherer Software-Qualität.4 Fazit Nichtsdestotrotz ist Vorsicht mit diesen Konstrukten in performance-relevante Abfragen geboten. Dadurch dass im Hintergrund eine Zustandsmaschine verwalten wird, entsteht einiges an Overhead dessen Verarbeitung zusätzliche Zeit kostet - ca. 20 bis 100 Prozent. Darüber hinaus ist auch das Arbeiten ohne Recycling schnell ein Performance-Gap. Allerdings ist deklarativer LINQ-Code viel eleganter, fehlerfreier und wartungsfreundlicher als das manuelle Iterieren, Vergleichen und Aufbauen einer Ergebnisliste. Der Code-Umfang verringert sich erfahrungsgemäß im Schnitt um 75 bis 90 Prozent! Dafür warte ich gerne ein paar Millisekunden länger. Wie so oft muss abgewogen werden zwischen Wartbarkeit und Performance - wobei für mich Wartbarkeit zunehmend an Priorität gewinnt. Zumeist ist sowieso nicht der Code sondern der Anwender die Bremse im Prozess. Demo-Quellcode support.esri.de   [1] Wikipedia: LINQ http://de.wikipedia.org/wiki/LINQ [2] Wikipedia: Zustandsmaschine http://de.wikipedia.org/wiki/Endlicher_Automat [3] Charlie Calverts Blog: LINQ and Deferred Execution http://blogs.msdn.com/b/charlie/archive/2007/12/09/deferred-execution.aspx [4] Clean Code Developer - gelber Grad/Automatisierte Unit Tests http://www.clean-code-developer.de/Gelber-Grad.ashx#Automatisierte_Unit_Tests_8

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• How and when to use UNIT testing properly

  - by Zebs

  I am an iOS developer. I have read about unit testing and how it is used to test specific pieces of your code. A very quick example has to do with processing JSON data onto a database. The unit test reads a file from the project bundle and executes the method that is in charge of processing JSON data. But I dont get how this is different from actually running the app and testing with the server. So my question might be a bit general, but I honestly dont understand the proper use of unit testing, or even how it is useful; I hope the experienced programmers that surf around StackOverflow can help me. Any help is very much appreciated!

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• URL Routing in ASP.NET 4.0

  In the .NET Framework 3.5 SP1, Microsoft introduced ASP.NET Routing, which decouples the URL of a resource from the physical file on the web server. With ASP.NET Routing you, the developer, define routing rules map route patterns to a class that generates the content. For example, you might indicate that the URL <code>Categories/<i>CategoryName</i></code> maps to a class that takes the <i>CategoryName</i> and generates HTML that lists that category's products in a grid. With such a mapping, users could view products for the Beverages category by visiting <code>www.yoursite.com/Categories/Beverages</code>.In .NET 3.5 SP1, ASP.NET Routing was primarily designed for <a href="http://www.asp.net/mvc/">ASP.NET MVC</a>

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• New Year, New Position, New Opportunity and Adventures!

  - by D'Arcy Lussier

  2010 was an incredible year of change for me. On the personal side, we celebrated our youngest daughter’s first birthday and welcomed my oldest daughter into our family (both my girls are adopted). Professionally, I put on the first ever Prairie Developer Conference, the 3rd annual Winnipeg Code Camp, the Software Development and Evolution Conference, continued to build the technology community in Winnipeg, was awarded a Microsoft MVP award for the 4th year, created a certification program to help my employer, Protegra, attain Microsoft Partner status, and had great project work throughout the year. So now its 2011, and I’m looking ahead to new challenges and opportunities with a new employer. Starting in mid February I’ll be the Microsoft Practice Lead with Online Business Systems, a Microsoft partner here in Winnipeg! I’m very excited about working with such great people and helping continue delivering quality solutions and consulting that the organization has become known for. 2010 was great, but 2011 is shaping up to be a banner year both personally and professionally!

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• Striving to be boring - or at least have boring systems

  - by merrillaldrich

  A developer I work with, whom I respect a great deal, reminded me of this truism today. I'm not sure who came up with the original, but they deserve credit wherever they are: “A good system administrator is a bored system administrator.” As a DBA, this really rings true for me. Being a DBA should not be a thrilling job. Within reason, there should not be myriad surprises, nor a roller coaster ride, wondering what will break each day. There should not be numerous 2 AM calls or frantic fixes. If there...(read more)

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• Developing JSON API for a Carpool Engine

  - by Siddharth

  I am developing a new set of API methods for carpooling/cab booking, so if a developer needs to develop an app or webportal for carpooling, he can call my JSON API. Basically making it easy for developers. My API current has: AddVehicle AddJourney SearchJourney SubscribeToThisJourney(journey) SubscriberList(journey) to get list of people who have subscribed for this journey AcceptSubscription(subscriber) AcceptedSubcriberList SubscriberList to get list of providers I have subscribed to I need help with replacing subscriber with something else. It's difficult to remember, and confusing when you see 3 methods that mean very different things: SubscriberList, SubscribedToThisJourneyList and AcceptedSubscriberList. Confusing to remember. One is a list of who I have subscribed to Who has subscribed to me Whose subscription I have accepted How can I name these methods to make them easier to understand and remember?

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• Professional iOS Development as a Backup Career [closed]

  - by New Coder

  I am a research chemist by day and I am a self-taught hobbyist iOS programmer by night. I am in the process of developing a moderately complex iOS app and hope to launch it within a month or two. I love everything about iOS development (and programming in general). I want to know if iOS development could become a backup career for me if I loose my job. My question: Let's say I had a couple of apps in the app store, a solid foundation in objective-C and the apple frameworks and basic knowledge on network integrated apps. Without a formal CS degree, what other experience/knowledge would I need to land a job as a professional iOS developer? Forgive me if this question is out of bounds for this forum. If it is, suggestions on where to post such a question would be appreciated.

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• Browser-based MMOs (WebGL, WebSocket)

  - by Alon Gubkin

  Do you think it is technically possible to write a fully-fledged 3D MMO client with Browser JavaScript - WebGL for graphics, and WebSocket for Networking? Do you think future MMOs (and games generally) will wrriten with WebGL? Does today's JavaScript performance allow this? Let's say your development team was you as a developer, and another model creator (artist). Would you use a library like SceneJS for the game, or write straight WebGL? If you would use a library, but not SceneJS, please specify which. UPDATE (September 2012): RuneScape, which is a very popular 3D browser-based MMORPG that used Java Applets so far has announced that it will use HTML5 for their client (source). Java (left) and HTML5 (right)

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• How much should I charge an hour for freelance iOS development?

  - by Tyler Bell

  I am a fairly competent developer who already holds a job developing iOS applications. This job is through the university which I attend. The producer of the apps that I develop is always trying to set me up with some freelance opportunities to get my work out there and to get me some more work/experience. What is a reasonable price to charge (either hourly or per app)? I'd be working by myself, on my own equipment, from start to finish in the design process. Just wondering what a reasonable price was...I've heard up to $30? Thanks

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• finding the gedit plugin folder

  - by BlackSheep

  I am a bit confused as to where I should put externally downloaded plugins. I have tried putting them in: /usr/share/gedit/plugins ~/.local/gedit/plugins ~/.gnome2/gedit/plugins /usr/lib/gedit/plugins The way I have checked whether the plugins show up or not is going to Edit-Preferences-Plugins and looking for the ones I have downloaded (clickconfig, gedit-developer-plugins-...). Since I do not see any new plugins appearing, I have to assume that I am doing something wrong. None of these have worked. I am a bit tired of polluting my system. It's probably my own fault as it's written somewhere I have not thought to look. Please let me know how to add external plugins to gedit properly. I am running Ubuntu 11.10. My gedit version is 3.2.3 EDIT: I am still not able to solve this problem. I have tried the following folder now as well, and it hasn't worked: ~/.config/gedit/plugins

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• Choosing 3D modeling software Maya or 3D max?

  - by Kenneth J

  I've am a developer whose has spent most of my programming life developing web and business applications. I want to try my hand at something more challenging (but stay in the comfort of Visual Studio) ...perhaps XNA. Want 3D modeling software would be best for someone developing XNA? I have played with 3d MAX and Maya but never really did anything too involved. What are the pros and cons between them (in terms of game development)? Does one win out over the other for game development? Or is it pretty much just preference? I am new to game development and just trying to figure out the best tools to use before I really started. Any advice or other suggections would be greatly appreciated.

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• AJI Report #18 | Patrick Delancy On Code Smells and Anti-Patterns

  - by Jeff Julian

  Patrick Delancy, the first person we interviewed on the AJI Report, is joining us again for Episode 18. This time around Patrick explains what Code Smells and Anti-patterns are and how developers can learn from these issues in their code. Patrick takes the approach of addressing your code in his presentations instead of pointing fingers at others. We spend a lot of time talking about how to address a developer with bad practices in place that would show up on the radar as a Code Smell or Anti-Pattern without making them feel inferior. Patrick also list out a few open-source frameworks that use good patterns and practices as well as how he continues his education through interacting with other developers. Listen to the Show Site: http://patrickdelancy.com Twitter: @PatrickDelancy LinkedIn: LinkedIn Google+: Profile

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• How to restore your production database without needing additional storage

  - by David Atkinson

  Production databases can get very large. This in itself is to be expected, but when a copy of the database is needed the database must be restored, requiring additional and costly storage.  For example, if you want to give each developer a full copy of your production server, you'll need n times the storage cost for your n-developer team. The same is true for any test databases that are created during the course of your project lifecycle. If you've read my previous blog posts, you'll be aware that I've been focusing on the database continuous integration theme. In my CI setup I create a "production"-equivalent database directly from its source control representation, and use this to test my upgrade scripts. Despite this being a perfectly valid and practical thing to do as part of a CI setup, it's not the exact equivalent to running the upgrade script on a copy of the actual production database. So why shouldn't I instead simply restore the most recent production backup as part of my CI process? There are two reasons why this would be impractical. 1. My CI environment isn't an exact copy of my production environment. Indeed, this would be the case in a perfect world, and it is strongly recommended as a good practice if you follow Jez Humble and David Farley's "Continuous Delivery" teachings, but in practical terms this might not always be possible, especially where storage is concerned. It may just not be possible to restore a huge production database on the environment you've been allotted. 2. It's not just about the storage requirements, it's also the time it takes to do the restore. The whole point of continuous integration is that you are alerted as early as possible whether the build (yes, the database upgrade script counts!) is broken. If I have to run an hour-long restore each time I commit a change to source control I'm just not going to get the feedback quickly enough to react. So what's the solution? Red Gate has a technology, SQL Virtual Restore, that is able to restore a database without using up additional storage. Although this sounds too good to be true, the explanation is quite simple (although I'm sure the technical implementation details under the hood are quite complex!) Instead of restoring the backup in the conventional sense, SQL Virtual Restore will effectively mount the backup using its HyperBac technology. It creates a data and log file, .vmdf, and .vldf, that becomes the delta between the .bak file and the virtual database. This means that both read and write operations are permitted on a virtual database as from SQL Server's point of view it is no different from a conventional database. Instead of doubling the storage requirements upon a restore, there is no 'duplicate' storage requirements, other than the trivially small virtual log and data files (see illustration below). The benefit is magnified the more databases you mount to the same backup file. This technique could be used to provide a large development team a full development instance of a large production database. It is also incredibly easy to set up. Once SQL Virtual Restore is installed, you simply run a conventional RESTORE command to create the virtual database. This is what I have running as part of a nightly "release test" process triggered by my CI tool. RESTORE DATABASE WidgetProduction_virtual FROM DISK=N'C:\WidgetWF\ProdBackup\WidgetProduction.bak' WITH MOVE N'WidgetProduction' TO N'C:\WidgetWF\ProdBackup\WidgetProduction_WidgetProduction_Virtual.vmdf', MOVE N'WidgetProduction_log' TO N'C:\WidgetWF\ProdBackup\WidgetProduction_log_WidgetProduction_Virtual.vldf', NORECOVERY, STATS=1, REPLACE GO RESTORE DATABASE mydatabase WITH RECOVERY   Note the only change from what you would do normally is the naming of the .vmdf and .vldf files. SQL Virtual Restore intercepts this by monitoring the extension and applies its magic, ensuring the 'virtual' restore happens rather than the conventional storage-heavy restore. My automated release test then applies the upgrade scripts to the virtual production database and runs some validation tests, giving me confidence that were I to run this on production for real, all would go smoothly. For illustration, here is my 8Gb production database: And its corresponding backup file: Here are the .vldf and .vmdf files, which represent the only additional used storage for the new database following the virtual restore.   The beauty of this product is its simplicity. Once it is installed, the interaction with the backup and virtual database is exactly the same as before, as the clever stuff is being done at a lower level. SQL Virtual Restore can be downloaded as a fully functional 14-day trial. Technorati Tags: SQL Server

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• Are CK Metrics still considered useful? Is there an open source tool to help?

  - by DeveloperDon

  Chidamber & Kemerer proposed several metrics for object oriented code. Among them, depth of inheritance tree, weighted number of methods, number of member functions, number of children, and coupling between objects. Using a base of code, they tried to correlated these metrics to the defect density and maintenance effort using covariant analysis. Are these metrics actionable in projects? Perhaps they can guide refactoring. For example weighted number of methods might show which God classes needed to be broken into more cohesive classes that address a single concern. Is there approach superseded by a better method, and is there a tool that can identify problem code, particularly in moderately large project being handed off to a new developer or team?

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• Elore konfigur&aacute;lt Virtualbox image-ek

  - by Lajos Sárecz

  Korábban már írtam arról, hogy Oracle VM Template-ek érhetok el a fontosabb termékeink esetében, így elkerülheto Oracle VM használata esetén az Oracle szoftverek telepítésének macerája. Azonban az Oracle VM tipikusan szerver környezetben használatos virtualizációs technológia, így aki az Oracle VM Virtualbox-ot szeretné használni saját gépén Oracle környezetek kialakítására, azok számára jó hír, hogy Virtualbox esetében is számos kész környezet, image töltheto le. Oracle Database esetén a legfrissebb 11gR2 verzió töltheto így le, mely tartalmazza az In-Memory Database Cache kiegészítést, az SQL Developer-t (Data Modeler-rel együtt), a JDeveloper-t és természetesen az Application Express-t is. Mindezt Oracle Linux-on, de van lehetoség Solaris image, Java, vagy akár SOA & BPM fejlesztoi környezet letöltésére is.

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• Repeat row headers after Page Break

  - by klaus.fabian

  The lead developer of the FO engine send me by chance an email about a REALLY nice feature I did not know about. Did you ever encounter a long table with merged cells, where the merged cell went on to the next page? While column headers are by default repeated on the next page, row headers are not. Tables with group-left column and pivot tables are prime examples where this problem occurs. I have seen reports where merged cells could go over multiple pages and you would need to back to find the row header on previous pages. The BI Publisher RTF templates have a special tag you can added to a merged cell to repeat the contents after each page break. You just need to add the following (wordy) tag to the next merged table cell: true Example: 2nd page of report before adding the tag 2nd page of report after adding the tag. Thought you might want to know. Klaus

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• Advancing Code Review and Unit Testing Practice

  - by Graviton

  As a team lead managing a group of developers with no experience ( and see no need) in code review and unit testing, how can you advance code review and unit testing practice? How are you going to create a way so that code review and unit testing to naturally fit into the developer's flow? One of the resistance of these two areas is that "we are always tight on dateline, so no time for code review and unit testing". Another resistance for code review is that we currently don't know how to do it. Should we review the code upon every check-in, or review the code at a specified date?

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