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• Optimize SUMMARIZE with ADDCOLUMNS in Dax #ssas #tabular #dax #powerpivot

  - by Marco Russo (SQLBI)

  If you started using DAX as a query language, you might have encountered some performance issues by using SUMMARIZE. The problem is related to the calculation you put in the SUMMARIZE, by adding what are called extension columns, which compute their value within a filter context defined by the rows considered in the group that the SUMMARIZE uses to produce each row in the output. Most of the time, for simple table expressions used in the first parameter of SUMMARIZE, you can optimize performance by removing the extended columns from the SUMMARIZE and adding them by using an ADDCOLUMNS function. In practice, instead of writing SUMMARIZE( <table>, <group_by_column>, <column_name>, <expression> ) you can write: ADDCOLUMNS(     SUMMARIZE( <table>, <group by column> ),     <column_name>, CALCULATE( <expression> ) ) The performance difference might be huge (orders of magnitude) but this optimization might produce a different semantic and in these cases it should not be used. A longer discussion of this topic is included in my Best Practices Using SUMMARIZE and ADDCOLUMNS article on SQLBI, which also include several details about the DAX syntax with extended columns. For example, did you know that you can create an extended column in SUMMARIZE and ADDCOLUMNS with the same name of existing measures? It is *not* a good thing to do, and by reading the article you will discover why. Enjoy DAX!

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• Ubuntu, User Accounts messed up

  - by Vor

  I need to fix Ubuntu Accounts some how but don't really see how it could be done. The problem is: files /etc/passwd and /etc/hostname and /etc/hosts where changed. /etc/passwd After John:x:1000:1000:John,,,:/home/serg:/bin/bash Befoure serg:x:1000:1000:John,,,:/home/serg:/bin/bash /etc/hosts After 127.0.0.1 localhost 127.0.1.1 John-The-Rippe Befoure 127.0.0.1 localhost 127.0.1.1 serg-Protege /etc/hostname After John-The-Ripper Befoure serg-PORTEGE-Z835 I was trying to simply changed this files but can not do this because permission denied. When I'm trying to login as a root I got this message: John@John-The-Ripper:~$ sudo -s [sudo] password for John: John is not in the sudoers file. This incident will be reported The file sudoers is empty: John@John-The-Ripper:~$ vi /etc/sudoers When I type users in cp: John@John-The-Ripper:~$ users John John When I type id, I got this: John@John-The-Ripper:~$ id uid=1000(John) gid=1000(serg) groups=1000(serg) This doesn't work eather: John@John-The-Ripper:~$ usermod -l John serg usermod: user 'serg' does not exist John@John-The-Ripper:~$ adduser serg adduser: Only root may add a user or group to the system. ater. Then I tried to go to the GRUB menu and from there log in as a root. I did this, but however When I tryed to create user serg, It gave me an error that group already exist. When I tried to change /etc/passwd it said 'permission denied' And this doens't do the trick: John@John-The-Ripper:~$ visudo visudo: /etc/sudoers: Permission denied visudo: /etc/sudoers: Permission denied Also The last thing I tried to do is to create a bootable USB and reinstall ubuntu, however I can not open USB-Creator because it asked me a root passwd. But it doesn't work. HELP ME PLEASE =)))

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• Entity Framework v1 &ndash; tips and Tricks Part 3

  - by Rohit Gupta

  General Tips on Entity Framework v1 & Linq to Entities: ToTraceString() If you need to know the underlying SQL that the EF generates for a Linq To Entities query, then use the ToTraceString() method of the ObjectQuery class. (or use LINQPAD) Note that you need to cast the LINQToEntities query to ObjectQuery before calling TotraceString() as follows: 1: string efSQL = ((ObjectQuery)from c in ctx.Contact 2: where c.Address.Any(a => a.CountryRegion == "US") 3: select c.ContactID).ToTraceString(); ================================================================================ MARS or MultipleActiveResultSet When you create a EDM Model (EDMX file) from the database using Visual Studio, it generates a connection string with the same name as the name of the EntityContainer in CSDL. In the ConnectionString so generated it sets the MultipleActiveResultSet attribute to true by default. So if you are running the following query then it streams multiple readers over the same connection: 1: using (BAEntities context = new BAEntities()) 2: { 3: var cons = 4: from con in context.Contacts 5: where con.FirstName == "Jose" 6: select con; 7: foreach (var c in cons) 8: { 9: if (c.AddDate < new System.DateTime(2007, 1, 1)) 10: { 11: c.Addresses.Load(); 12: } 13: } 14: } ================================================================================= Explicitly opening and closing EntityConnection When you call ToList() or foreach on a LINQToEntities query the EF automatically closes the connection after all the records from the query have been consumed. Thus if you need to run many LINQToEntities queries over the same connection then explicitly open and close the connection as follows: 1: using (BAEntities context = new BAEntities()) 2: { 3: context.Connection.Open(); 4: var cons = from con in context.Contacts where con.FirstName == "Jose" 5: select con; 6: var conList = cons.ToList(); 7: var allCustomers = from con in context.Contacts.OfType<Customer>() 8: select con; 9: var allcustList = allCustomers.ToList(); 10: context.Connection.Close(); 11: } ====================================================================== Dispose ObjectContext only if required After you retrieve entities using the ObjectContext and you are not explicitly disposing the ObjectContext then insure that your code does consume all the records from the LinqToEntities query by calling .ToList() or foreach statement, otherwise the the database connection will remain open and will be closed by the garbage collector when it gets to dispose the ObjectContext. Secondly if you are making updates to the entities retrieved using LinqToEntities then insure that you dont inadverdently dispose of the ObjectContext after the entities are retrieved and before calling .SaveChanges() since you need the SAME ObjectContext to keep track of changes made to the Entities (by using ObjectStateEntry objects). So if you do need to explicitly dispose of the ObjectContext do so only after calling SaveChanges() and only if you dont need to change track the entities retrieved any further. ======================================================================= SQL InjectionAttacks under control with EFv1 LinqToEntities and LinqToSQL queries are parameterized before they are sent to the DB hence they are not vulnerable to SQL Injection attacks. EntitySQL may be slightly vulnerable to attacks since it does not use parameterized queries. However since the EntitySQL demands that the query be valid Entity SQL syntax and valid native SQL syntax at the same time. So the only way one can do a SQLInjection Attack is by knowing the SSDL of the EDM Model and be able to write the correct EntitySQL (note one cannot append regular SQL since then the query wont be a valid EntitySQL syntax) and append it to a parameter. ====================================================================== Improving Performance You can convert the EntitySets and AssociationSets in a EDM Model into precompiled Views using the edmgen utility. for e.g. the Customer Entity can be converted into a precompiled view using edmgen and all LinqToEntities query against the contaxt.Customer EntitySet will use the precompiled View instead of the EntitySet itself (the same being true for relationships (EntityReference & EntityCollections of a Entity)). The advantage being that when using precompiled views the performance will be much better. The syntax for generating precompiled views for a existing EF project is : edmgen /mode:ViewGeneration /inssdl:BAModel.ssdl /incsdl:BAModel.csdl /inmsl:BAModel.msl /p:Chap14.csproj Note that this will only generate precompiled views for EntitySets and Associations and not for existing LinqToEntities queries in the project.(for that use CompiledQuery.Compile<>) Secondly if you have a LinqToEntities query that you need to run multiple times, then one should precompile the query using CompiledQuery.Compile method. The CompiledQuery.Compile<> method accepts a lamda expression as a parameter, which denotes the LinqToEntities query  that you need to precompile. The following is a example of a lamda that we can pass into the CompiledQuery.Compile() method 1: Expression<Func<BAEntities, string, IQueryable<Customer>>> expr = (BAEntities ctx1, string loc) => 2: from c in ctx1.Contacts.OfType<Customer>() 3: where c.Reservations.Any(r => r.Trip.Destination.DestinationName == loc) 4: select c; Then we call the Compile Query as follows: 1: var query = CompiledQuery.Compile<BAEntities, string, IQueryable<Customer>>(expr); 2:  3: using (BAEntities ctx = new BAEntities()) 4: { 5: var loc = "Malta"; 6: IQueryable<Customer> custs = query.Invoke(ctx, loc); 7: var custlist = custs.ToList(); 8: foreach (var item in custlist) 9: { 10: Console.WriteLine(item.FullName); 11: } 12: } Note that if you created a ObjectQuery or a Enitity SQL query instead of the LINQToEntities query, you dont need precompilation for e.g. 1: An Example of EntitySQL query : 2: string esql = "SELECT VALUE c from Contacts AS c where c is of(BAGA.Customer) and c.LastName = 'Gupta'"; 3: ObjectQuery<Customer> custs = CreateQuery<Customer>(esql); 1: An Example of ObjectQuery built using ObjectBuilder methods: 2: from c in Contacts.OfType<Customer>().Where("it.LastName == 'Gupta'") 3: select c This is since the Query plan is cached and thus the performance improves a bit, however since the ObjectQuery or EntitySQL query still needs to materialize the results into Entities hence it will take the same amount of performance hit as with LinqToEntities. However note that not ALL EntitySQL based or QueryBuilder based ObjectQuery plans are cached. So if you are in doubt always create a LinqToEntities compiled query and use that instead ============================================================ GetObjectStateEntry Versus GetObjectByKey We can get to the Entity being referenced by the ObjectStateEntry via its Entity property and there are helper methods in the ObjectStateManager (osm.TryGetObjectStateEntry) to get the ObjectStateEntry for a entity (for which we know the EntityKey). Similarly The ObjectContext has helper methods to get an Entity i.e. TryGetObjectByKey(). TryGetObjectByKey() uses GetObjectStateEntry method under the covers to find the object, however One important difference between these 2 methods is that TryGetObjectByKey queries the database if it is unable to find the object in the context, whereas TryGetObjectStateEntry only looks in the context for existing entries. It will not make a trip to the database ============================================================= POCO objects with EFv1: To create POCO objects that can be used with EFv1. We need to implement 3 key interfaces: IEntityWithKey IEntityWithRelationships IEntityWithChangeTracker Implementing IEntityWithKey is not mandatory, but if you dont then we need to explicitly provide values for the EntityKey for various functions (for e.g. the functions needed to implement IEntityWithChangeTracker and IEntityWithRelationships). Implementation of IEntityWithKey involves exposing a property named EntityKey which returns a EntityKey object. Implementation of IEntityWithChangeTracker involves implementing a method named SetChangeTracker since there can be multiple changetrackers (Object Contexts) existing in memory at the same time. 1: public void SetChangeTracker(IEntityChangeTracker changeTracker) 2: { 3: _changeTracker = changeTracker; 4: } Additionally each property in the POCO object needs to notify the changetracker (objContext) that it is updating itself by calling the EntityMemberChanged and EntityMemberChanging methods on the changeTracker. for e.g.: 1: public EntityKey EntityKey 2: { 3: get { return _entityKey; } 4: set 5: { 6: if (_changeTracker != null) 7: { 8: _changeTracker.EntityMemberChanging("EntityKey"); 9: _entityKey = value; 10: _changeTracker.EntityMemberChanged("EntityKey"); 11: } 12: else 13: _entityKey = value; 14: } 15: } 16: ===================== Custom Property ==================================== 17:  18: [EdmScalarPropertyAttribute(IsNullable = false)] 19: public System.DateTime OrderDate 20: { 21: get { return _orderDate; } 22: set 23: { 24: if (_changeTracker != null) 25: { 26: _changeTracker.EntityMemberChanging("OrderDate"); 27: _orderDate = value; 28: _changeTracker.EntityMemberChanged("OrderDate"); 29: } 30: else 31: _orderDate = value; 32: } 33: } Finally you also need to create the EntityState property as follows: 1: public EntityState EntityState 2: { 3: get { return _changeTracker.EntityState; } 4: } The IEntityWithRelationships involves creating a property that returns RelationshipManager object: 1: public RelationshipManager RelationshipManager 2: { 3: get 4: { 5: if (_relManager == null) 6: _relManager = RelationshipManager.Create(this); 7: return _relManager; 8: } 9: } ============================================================ Tip : ProviderManifestToken – change EDMX File to use SQL 2008 instead of SQL 2005 To use with SQL Server 2008, edit the EDMX file (the raw XML) changing the ProviderManifestToken in the SSDL attributes from "2005" to "2008" ============================================================= With EFv1 we cannot use Structs to replace a anonymous Type while doing projections in a LINQ to Entities query. While the same is supported with LINQToSQL, it is not with LinqToEntities. For e.g. the following is not supported with LinqToEntities since only parameterless constructors and initializers are supported in LINQ to Entities. (the same works with LINQToSQL) 1: public struct CompanyInfo 2: { 3: public int ID { get; set; } 4: public string Name { get; set; } 5: } 6: var companies = (from c in dc.Companies 7: where c.CompanyIcon == null 8: select new CompanyInfo { Name = c.CompanyName, ID = c.CompanyId }).ToList(); ;

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• Standards Corner: OAuth WG Client Registration Problem

  - by Tanu Sood

  Phil Hunt is an active member of multiple industry standards groups and committees (see brief bio at the end of the post) and has spearheaded discussions, creation and ratifications of  Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-family:"Calibri","sans-serif"; mso-ascii- mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi- mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;} industry standards including the Kantara Identity Governance Framework, among others. Being an active voice in the industry standards development world, we have invited him to share his discussions, thoughts, news & updates, and discuss use cases, implementation success stories (and even failures) around industry standards on this monthly column. Author: Phil Hunt This afternoon, the OAuth Working Group will meet at IETF88 in Vancouver to discuss some important topics important to the maturation of OAuth. One of them is the OAuth client registration problem.OAuth (RFC6749) was initially developed with a simple deployment model where there is only monopoly or singleton cloud instance of a web API (e.g. there is one Facebook, one Google, on LinkedIn, and so on). When the API publisher and API deployer are the same monolithic entity, it easy for developers to contact the provider and register their app to obtain a client_id and credential.But what happens when the API is for an open source project where there may be 1000s of deployed copies of the API (e.g. such as wordpress). In these cases, the authors of the API are not the people running the API. In these scenarios, how does the developer obtain a client_id? An example of an "open deployed" API is OpenID Connect. Connect defines an OAuth protected resource API that can provide personal information about an authenticated user -- in effect creating a potentially common API for potential identity providers like Facebook, Google, Microsoft, Salesforce, or Oracle. In Oracle's case, Fusion applications will soon have RESTful APIs that are deployed in many different ways in many different environments. How will developers write apps that can work against an openly deployed API with whom the developer can have no prior relationship?At present, the OAuth Working Group has two proposals two consider: Dynamic RegistrationDynamic Registration was originally developed for OpenID Connect and UMA. It defines a RESTful API in which a prospective client application with no client_id creates a new client registration record with a service provider and is issued a client_id and credential along with a registration token that can be used to update registration over time.As proof of success, the OIDC community has done substantial implementation of this spec and feels committed to its use. Why not approve?Well, the answer is that some of us had some concerns, namely: Recognizing instances of software - dynamic registration treats all clients as unique. It has no defined way to recognize that multiple copies of the same client are being registered other then assuming if the registration parameters are similar it might be the same client. Versioning and Policy Approval of open APIs and clients - many service providers have to worry about change management. They expect to have approval cycles that approve versions of server and client software for use in their environment. In some cases approval might be wide open, but in many cases, approval might be down to the specific class of software and version. Registration updates - when does a client actually need to update its registration? Shouldn't it be never? Is there some characteristic of deployed code that would cause it to change? Options lead to complexity - because each client is treated as unique, it becomes unclear how the clients and servers will agree on what credentials forms are acceptable and what OAuth features are allowed and disallowed. Yet the reality is, developers will write their application to work in a limited number of ways. They can't implement all the permutations and combinations that potential service providers might choose. Stateful registration - if the primary motivation for registration is to obtain a client_id and credential, why can't this be done in a stateless fashion using assertions? Denial of service - With so much stateful registration and the need for multiple tokens to be issued, will this not lead to a denial of service attack / risk of resource depletion? At the very least, because of the information gathered, it would difficult for service providers to clean up "failed" registrations and determine active from inactive or false clients. There has yet to be much wide-scale "production" use of dynamic registration other than in small closed communities. Client Association A second proposal, Client Association, has been put forward by Tony Nadalin of Microsoft and myself. We took at look at existing use patterns to come up with a new proposal. At the Berlin meeting, we considered how WS-STS systems work. More recently, I took a review of how mobile messaging clients work. I looked at how Apple, Google, and Microsoft each handle registration with APNS, GCM, and WNS, and a similar pattern emerges. This pattern is to use an existing credential (mutual TLS auth), or client bearer assertion and swap for a device specific bearer assertion.In the client association proposal, the developer's registration with the API publisher is handled by having the developer register with an API publisher (as opposed to the party deploying the API) and obtaining a software "statement". Or, if there is no "publisher" that can sign a statement, the developer may include their own self-asserted software statement.A software statement is a special type of assertion that serves to lock application registration profile information in a signed assertion. The statement is included with the client application and can then be used by the client to swap for an instance specific client assertion as defined by section 4.2 of the OAuth Assertion draft and profiled in the Client Association draft. The software statement provides a way for service provider to recognize and configure policy to approve classes of software clients, and simplifies the actual registration to a simple assertion swap. Because the registration is an assertion swap, registration is no longer "stateful" - meaning the service provider does not need to store any information to support the client (unless it wants to). Has this been implemented yet? Not directly. We've only delivered draft 00 as an alternate way of solving the problem using well-known patterns whose security characteristics and scale characteristics are well understood. Dynamic Take II At roughly the same time that Client Association and Software Statement were published, the authors of Dynamic Registration published a "split" version of the Dynamic Registration (draft-richer-oauth-dyn-reg-core and draft-richer-oauth-dyn-reg-management). While some of the concerns above are addressed, some differences remain. Registration is now a simple POST request. However it defines a new method for issuing client tokens where as Client Association uses RFC6749's existing extension point. The concern here is whether future client access token formats would be addressed properly. Finally, Dyn-reg-core does not yet support software statements. Conclusion The WG has some interesting discussion to bring this back to a single set of specifications. Dynamic Registration has significant implementation, but Client Association could be a much improved way to simplify implementation of the overall OpenID Connect specification and improve adoption. In fairness, the existing editors have already come a long way. Yet there are those with significant investment in the current draft. There are many that have expressed they don't care. They just want a standard. There is lots of pressure on the working group to reach consensus quickly.And that folks is how the sausage is made.Note: John Bradley and Justin Richer recently published draft-bradley-stateless-oauth-client-00 which on first look are getting closer. Some of the details seem less well defined, but the same could be said of client-assoc and software-statement. I hope we can merge these specs this week. Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-family:"Calibri","sans-serif"; mso-ascii- mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi- mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;} About the Writer: Phil Hunt joined Oracle as part of the November 2005 acquisition of OctetString Inc. where he headed software development for what is now Oracle Virtual Directory. Since joining Oracle, Phil works as CMTS in the Identity Standards group at Oracle where he developed the Kantara Identity Governance Framework and provided significant input to JSR 351. Phil participates in several standards development organizations such as IETF and OASIS working on federation, authorization (OAuth), and provisioning (SCIM) standards.  Phil blogs at www.independentid.com and a Twitter handle of @independentid.

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• Java Spotlight Episode 105: Mark Reinhold on the Future of Java

  - by Roger Brinkley

  Our yearly interview with Mark Reinhold, Chief Java Architect, Java Platform Group on the future of Java. Right-click or Control-click to download this MP3 file. You can also subscribe to the Java Spotlight Podcast Feed to get the latest podcast automatically. If you use iTunes you can open iTunes and subscribe with this link:  Java Spotlight Podcast in iTunes. Show Notes News Two Java Update Releases New Java SE 6 software updates from Apple for OS X 10.8, 10.7 and 10.6 are now live and available to all customers via the Mac App Store / Software Update. The JavaFX Community Site on Java.net JSR 360: Connected Limited Device Configuration 8 JSR 361: Java ME Embedded Profile 2012 JCP EC Election Ballot open Meet the EC Candidates Recording and Materials Events Oct 22-23, Freescale Technology Forum - Japan, Tokyo, Japan Oct 23-25, EclipseCon Europe, Ludwigsburg, Germany Oct 30-Nov 1, Arm TechCon, Santa Clara, United States of America Oct 31, JFall, Hart van Holland, Netherlands Nov 2-3, JMaghreb, Rabat, Morocco Nov 5-9, Øredev Developer Conference, Malmö, Sweden Nov 13-17, Devoxx, Antwerp, Belgium Nov 20-22, DOAG 2012, Nuremberg, Germany Dec 3-5, jDays, Göteborg, Sweden Dec 4-6, JavaOne Latin America, Sao Paolo, Brazil Feature InterviewMark Reinhold is Chief Architect of the Java Platform Group at Oracle, where he works on the Java Platform, Standard Edition, and OpenJDK. His past contributions to the platform include character-stream readers and writers, reference objects, shutdown hooks, the NIO high-performance I/O APIs, library generification, and service loaders. Mark was the lead engineer for the 1.2 and 5.0 releases and the specification lead for Java SE 6. He is currently leading the Jigsaw and JDK 7 Projects in the OpenJDK Community. Mark holds a Ph.D. in Computer Science from the Massachusetts Institute of Technology. In this interview he discusses the future of Java Platform with regards to Jigsaw, Lambda, and Nashorn components as well as the OpenJDK community. What’s Cool QotD: Ubuntu 12.10 Release Notes on OpenJDK 7 New Lambda binary drop Development forest for Compact Profiles (JEP 161)

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• Clustering Basics and Challenges

  - by Karoly Vegh

  For upcoming posts it seemed to be a good idea to dedicate some time for cluster basic concepts and theory. This post misses a lot of details that would explode the articlesize, should you have questions, do not hesitate to ask them in the comments.  The goal here is to get some concepts straight. I can't promise to give you an overall complete definitions of cluster, cluster agent, quorum, voting, fencing, split brain condition, so the following is more of an explanation. Here we go. -------- Cluster, HA, failover, switchover, scalability -------- An attempted definition of a Cluster: A cluster is a set (2+) server nodes dedicated to keep application services alive, communicating through the cluster software/framework with eachother, test and probe health status of servernodes/services and with quorum based decisions and with switchover/failover techniques keep the application services running on them available. That is, should a node that runs a service unexpectedly lose functionality/connection, the other ones would take over the and run the services, so that availability is guaranteed. To provide availability while strictly sticking to a consistent clusterconfiguration is the main goal of a cluster.  At this point we have to add that this defines a HA-cluster, a High-Availability cluster, where the clusternodes are planned to run the services in an active-standby, or failover fashion. An example could be a single instance database. Some applications can be run in a distributed or scalable fashion. In the latter case instances of the application run actively on separate clusternodes serving servicerequests simultaneously. An example for this version could be a webserver that forwards connection requests to many backend servers in a round-robin way. Or a database running in active-active RAC setup.  -------- Cluster arhitecture, interconnect, topologies -------- Now, what is a cluster made of? Servers, right. These servers (the clusternodes) need to communicate. This of course happens over the network, usually over dedicated network interfaces interconnecting all the clusternodes. These connection are called interconnects.How many clusternodes are in a cluster? There are different cluster topologies. The most simple one is a clustered pair topology, involving only two clusternodes:  There are several more topologies, clicking the image above will take you to the relevant documentation. Also, to answer the question Solaris Cluster allows you to run up to 16 servers in a cluster. Where shall these clusternodes be placed? A very important question. The right answer is: It depends on what you plan to achieve with the cluster. Do you plan to avoid only a server outage? Then you can place them right next to eachother in the datacenter. Do you need to avoid DataCenter outage? In that case of course you should place them at least in different fire zones. Or in two geographically distant DataCenters to avoid disasters like floods, large-scale fires or power outages. We call this a stretched- or campus cluster, the clusternodes being several kilometers away from eachother. To cover really large distances, you probably need to move to a GeoCluster, which is a different kind of animal.  What is a geocluster? A Geographic Cluster in Solaris Cluster terms is actually a metacluster between two, separate (locally-HA) clusters.  -------- Cluster resource types, agents, resources, resource groups -------- So how does the cluster manage my applications? The cluster needs to start, stop and probe your applications. If you application runs, the cluster needs to check regularly if the application state is healthy, does it respond over the network, does it have all the processes running, etc. This is called probing. If the cluster deems the application is in a faulty state, then it can try to restart it locally or decide to switch (stop on node A, start on node B) the service. Starting, stopping and probing are the three actions that a cluster agent does. There are many different kinds of agents included in Solaris Cluster, but you can build your own too. Examples are an agent that manages (mounts, moves) ZFS filesystems, or the Oracle DB HA agent that cares about the database, or an agent that moves a floating IP address between nodes. There are lots of other agents included for Apache, Tomcat, MySQL, Oracle DB, Oracle Weblogic, Zones, LDoms, NFS, DNS, etc.We also need to clarify the difference between a cluster resource and the cluster resource group.A cluster resource is something that is managed by a cluster agent. Cluster resource types are included in Solaris cluster (see above, e.g. HAStoragePlus, HA-Oracle, LogicalHost). You can group cluster resources into cluster resourcegroups, and switch these groups together from one node to another. To stick to the example above, to move an Oracle DB service from one node to another, you have to switch the group between nodes, and the agents of the cluster resources in the group will do the following:  On node A Shut down the DB Unconfigure the LogicalHost IP the DB Listener listens on unmount the filesystem   Then, on node B: mount the FS configure the IP  startup the DB -------- Voting, Quorum, Split Brain Condition, Fencing, Amnesia -------- How do the clusternodes agree upon their action? How do they decide which node runs what services? Another important question. Running a cluster is a strictly democratic thing.Every node has votes, and you need the majority of votes to have the deciding power. Now, this is usually no problem, clusternodes think very much all alike. Still, every action needs to be governed upon in a productive system, and has to be agreed upon. Agreeing is easy as long as the clusternodes all behave and talk to eachother over the interconnect. But if the interconnect is gone/down, this all gets tricky and confusing. Clusternodes think like this: "My job is to run these services. The other node does not answer my interconnect communication, it must be down. I'd better take control and run the services!". The problem is, as I have already mentioned, clusternodes very much think alike. If the interconnect is gone, they all assume the other node is down, and they all want to mount the data backend, enable the IP and run the database. Double IPs, double mounts, double DB instances - now that is trouble. Also, in a 2-node cluster they both have only 50% of the votes, that is, they themselves alone are not allowed to run a cluster.  This is where you need a quorum device. According to Wikipedia, the "requirement for a quorum is protection against totally unrepresentative action in the name of the body by an unduly small number of persons.". They need additional votes to run the cluster. For this requirement a 2-node cluster needs a quorum device or a quorum server. If the interconnect is gone, (this is what we call a split brain condition) both nodes start to race and try to reserve the quorum device to themselves. They do this, because the quorum device bears an additional vote, that could ensure majority (50% +1). The one that manages to lock the quorum device (e.g. if it's an FC LUN, it SCSI reserves it) wins the right to build/run a cluster, the other one - realizing he was late - panics/reboots to ensure the cluster config stays consistent.  Losing the interconnect isn't only endangering the availability of services, but it also endangers the cluster configuration consistence. Just imagine node A being down and during that the cluster configuration changes. Now node B goes down, and node A comes up. It isn't uptodate about the cluster configuration's changes so it will refuse to start a cluster, since that would lead to cluster amnesia, that is the cluster had some changes, but now runs with an older cluster configuration repository state, that is it's like it forgot about the changes.  Also, to ensure application data consistence, the clusternode that wins the race makes sure that a server that isn't part of or can't currently join the cluster can access the devices. This procedure is called fencing. This usually happens to storage LUNs via SCSI reservation.  Now, another important question: Where do I place the quorum disk?  Imagine having two sites, two separate datacenters, one in the north of the city and the other one in the south part of it. You run a stretched cluster in the clustered pair topology. Where do you place the quorum disk/server? If you put it into the north DC, and that gets hit by a meteor, you lose one clusternode, which isn't a problem, but you also lose your quorum, and the south clusternode can't keep the cluster running lacking the votes. This problem can't be solved with two sites and a campus cluster. You will need a third site to either place the quorum server to, or a third clusternode. Otherwise, lacking majority, if you lose the site that had your quorum, you lose the cluster. Okay, we covered the very basics. We haven't talked about virtualization support, CCR, ClusterFilesystems, DID devices, affinities, storage-replication, management tools, upgrade procedures - should those be interesting for you, let me know in the comments, along with any other questions. Given enough demand I'd be glad to write a followup post too. Now I really want to move on to the second part in the series: ClusterInstallation.  Oh, as for additional source of information, I recommend the documentation: http://docs.oracle.com/cd/E23623_01/index.html, and the OTN Oracle Solaris Cluster site: http://www.oracle.com/technetwork/server-storage/solaris-cluster/index.html

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• LINQ: Single vs. First

  - by Paulo Morgado

  I’ve witnessed and been involved in several discussions around the correctness or usefulness of the Single method in the LINQ API. The most common argument is that you are querying for the first element on the result set and an exception will be thrown if there’s more than one element. The First method should be used instead, because it doesn’t throw if the result set has more than one item. Although the documentation for Single states that it returns a single, specific element of a sequence of values, it actually returns THE single, specific element of a sequence of ONE value. One you use the Single method in your code you are asserting that your query will result in a scalar result instead of a result set of arbitrary length. On the other hand, the documentation for First states that it returns the first element of a sequence of arbitrary length. Imagine you want to catch a taxi. You go the the taxi line and catch the FIRST one, no matter how many are there. On the other hand, if you go the the parking lot to get your car, you want the SINGLE one specific car that’s yours. If your “query” “returns” more than one car, it’s an exception. Either because it “returned” not only your car or you happen to have more than one car in that parking lot. In either case, you can only drive one car at once and you’ll need to refine your “query”.

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• Part 2: Career development as a Software Developer without becoming a manager.

  - by albertpascual

  Seems like my previous post inspired by the work of Michael “Doc” Norton was a great success for the amount of emails I have received. Yet amazed how many people didn’t want to discuss their questions in the comments  sections. I would encourage people to be more public, still I would like to reply to all of you on this public media. I still welcome those emails. What I found out is that many people feels like me, they want to be developers and still be compensated for their experience without wanting to take a job as a manager. Their perfect day is a full day of coding and learning. Many believe their companies will never pay a manager’s salary to a developer no matter what. Most of you ask how to get the ball rolling. And is the later that I’m addressing here, the previous group, will never try. What companies understand developers value and where can I find them? This is a very difficult question to ask, I don’t have a list of those companies or departments, I have seen in my past signs in companies bending backwards to compensate, in more ways the monetary, a developer that is a good resource to them. Allowing the person to move out of the state and still let them work for the company from home is a sign that company goes by individual cases. Allowing them to go to conference that will not benefit the company is another big sign. Simple signs like flexible hours and letting some people work from home. To see those signs you need to be working in that company for awhile and look at the departments where the manager is taking care of their employees in individual cases. Look for the department where people get quiet extra perks, where some people in the department work from home or remotely. In my experience, but not always true, medium to big companies, are prompt to recognize good developers. Then again, some companies just don’t get it and is when you see many technical people managing developers. For all the people that email me stating that developers can also be very good managers, I do not disagree, I just think that a good developers loves writing code, when you remove that part the better salary isn’t enough to keep a developer happy. Burned out developers appreciate being promoted to managers. How do I know I work in a bad company? In my experience I have been a consultant and seen many companies, a few signs I have learned about companies that will not recognize good developers are: When the turn over is pretty high, when developers are moving out in a big rate, no rocket scientist needs to tap you in the shoulder. When the company is looking always to outsource their development resources. The product is not that interesting nor the company cares too much for their final result and support. Code sweat shops. You’ll know when you start working in one of those. Run for the hills! Where do I start? Disclaimer: I have only based this post on Michael “Doc” Norton, this is just my interpretation and ideas. First thing is to look at Michael “Doc” Norton presentation Take Control of Your Development Career http://docondev.blogspot.com/ That should be the first thing any developer should look and follow like it was a pattern. I would personally recommend to find some language or pattern you are interested with and learn it, learn something that will make you happy. Second, join a User Group and get involve in the community. There are hundreds of user groups, and I’m sure you’ll find one in your city or near you town. Code Camps are Developers Meet Ups are also good resources. Third, I would join a open source project you are interested or better yet, create a new open source project with the new technology that you have learn and get coding. Fourth, create a Twitter account and follow the people that talks about the technology you are interested on. If you follow this 4 steps above I think you’ll be on your way, after they are complete, when you release your Open Source project you can say that you accomplished the first steps. Now, do not expect anything to change in your career life, you are changing and should not expect anything in return, besides borrowing some time from sleeping and your family. Creating a good schedule may help you, I find wasted time in many places that I use. Flying for work is actually one of those that allows me to do my best work on a airplane, don’t need to borrow time from anywhere else. Making sure you always have a light, charged laptop is so important. Next steps following the Michael “Doc” Norton Pattern or my interpretation of. First, help run a user group or better yet, start a new user group. I’ll add, as well, go to one conference a year and free development events around your city; Code Camps, Geek Dinners, etc. There are many free events sponsored by different companies for developers to get to know their products, I highly recommend those as the way to get connected. Second, chose a mentor, this is a very hard thing to do I experienced, find an expert in the technology you are learning that has the time for you, it is difficult, I wish you best of luck. Third, learn another technology or pattern, open your horizons a little bit more. Why not, if you had fun previously, keep doing it. Fourth, get involved in forums to answer and ask questions, getting notice in public forums is rewarding for your ego after such a long journey. Final steps following the Michael “Doc” Norton Pattern Teach what you know, become humble on your knowledge, find as many opportunities to teach and to get involved with the community, bring all that to your day job. Mr. Norton talks about getting naked, expose yourself to others in your knowledge and what you do not know. You are never too important for small opportunities, yet don’t  be afraid to take anything big and learn from the experience. Anytime you have the opportunity to talk to somebody that has reach the point the community knows his or her name, means that you should learn from it. Take opportunities that won’t make you money, yet will make you happy. Sometimes you need to spend money and time. Register talks in Code Camps and Dev Meet Ups, those are free, also go to Conference, Development Summits and Geek Diners for example. One day, people will pay you to attend. When will all these pay off? I don’t know. I’m still in the path, there are a few things that during your journey you may get little acknowledgements that you are in the correct path. In my case I think those are the little signs that tells you about your journey. I got awarded the Microsoft Most Valuable Professional for ASP.NET in 2007, 2008, 2009 and 2010. I got selected to speak at the DevConnections in Las Vegas in 2010 and Orlando 2011. I do believe that I do have a long way to go, yet what I do makes me happy and I hope I can keep doing for years to come. Every year I can see an improvement on my code, and more frameworks and languages are under my belt, I learn to embrace them all as well as in my daily job, I have been able to work in a few projects beyond my department. I’m a learner and believer of the Michael “Doc” Norton pattern. Looking forward to learn more about it to be able to apply it better. In my short journey I now see my mistakes, I did a few things right, I have been listening the intelligent people and not being afraid to move along the technology changes. In my professional life, I have tried to avoid being placed in only one technology and product. I have always share my code and never confused anybody that wanted to take over any of my projects, I didn’t think anything I created as my own nor care too much when politics didn’t see my vision. I stayed flexible, ready and visible, yet humble. I keep my head just below the clouds, and avoided managers meetings. I credit my manager for my success, and I faulted publicly only myself for the failures. Hope this helps. Cheers, Al Follow me in Twitter  Read my previous post tweetmeme_url = 'http://weblogs.asp.net/albertpascual/archive/2010/12/09/part-2-career-development-as-a-software-developer-without-becoming-a-manager.aspx'; tweetmeme_source = 'alpascual';

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• MVC Automatic Menu

  - by Nuri Halperin

  An ex-colleague of mine used to call his SQL script generator "Super-Scriptmatic 2000". It impressed our then boss little, but was fun to say and use. We called every batch job and script "something 2000" from that day on. I'm tempted to call this one Menu-Matic 2000, except it's waaaay past 2000. Oh well. The problem: I'm developing a bunch of stuff in MVC. There's no PM to generate mounds of requirements and there's no Ux Architect to create wireframe. During development, things change. Specifically, actions get renamed, moved from controller x to y etc. Well, as the site grows, it becomes a major pain to keep a static menu up to date, because the links change. The HtmlHelper doesn't live up to it's name and provides little help. How do I keep this growing list of pesky little forgotten actions reigned in? The general plan is: Decorate every action you want as a menu item with a custom attribute Reflect out all menu items into a structure at load time Render the menu using as CSS  friendly <ul><li> HTML. The MvcMenuItemAttribute decorates an action, designating it to be included as a menu item: [AttributeUsage(AttributeTargets.Method, AllowMultiple = true)] public class MvcMenuItemAttribute : Attribute {   public string MenuText { get; set; }   public int Order { get; set; }   public string ParentLink { get; set; }   internal string Controller { get; set; }   internal string Action { get; set; }     #region ctor   public MvcMenuItemAttribute(string menuText) : this(menuText, 0) { } public MvcMenuItemAttribute(string menuText, int order) { MenuText = menuText; Order = order; }       internal string Link { get { return string.Format("/{0}/{1}", Controller, this.Action); } }   internal MvcMenuItemAttribute ParentItem { get; set; } #endregion } The MenuText allows overriding the text displayed on the menu. The Order allows the items to be ordered. The ParentLink allows you to make this item a child of another menu item. An example action could then be decorated thusly: [MvcMenuItem("Tracks", Order = 20, ParentLink = "/Session/Index")] . All pretty straightforward methinks. The challenge with menu hierarchy becomes fairly apparent when you try to render a menu and highlight the "current" item or render a breadcrumb control. Both encounter an  ambiguity if you allow a data source to have more than one menu item with the same URL link. The issue is that there is no great way to tell which link a person click. Using referring URL will fail if a user bookmarked the page. Using some extra query string to disambiguate duplicate URLs essentially changes the links, and also ads a chance of collision with other query parameters. Besides, that smells. The stock ASP.Net sitemap provider simply disallows duplicate URLS. I decided not to, and simply pick the first one encountered as the "current". Although it doesn't solve the issue completely – one might say they wanted the second of the 2 links to be "current"- it allows one to include a link twice (home->deals and products->deals etc), and the logic of deciding "current" is easy enough to explain to the customer. Now that we got that out of the way, let's build the menu data structure: public static List<MvcMenuItemAttribute> ListMenuItems(Assembly assembly) { var result = new List<MvcMenuItemAttribute>(); foreach (var type in assembly.GetTypes()) { if (!type.IsSubclassOf(typeof(Controller))) { continue; } foreach (var method in type.GetMethods()) { var items = method.GetCustomAttributes(typeof(MvcMenuItemAttribute), false) as MvcMenuItemAttribute[]; if (items == null) { continue; } foreach (var item in items) { if (String.IsNullOrEmpty(item.Controller)) { item.Controller = type.Name.Substring(0, type.Name.Length - "Controller".Length); } if (String.IsNullOrEmpty(item.Action)) { item.Action = method.Name; } result.Add(item); } } } return result.OrderBy(i => i.Order).ToList(); } Using reflection, the ListMenuItems method takes an assembly (you will hand it your MVC web assembly) and generates a list of menu items. It digs up all the types, and for each one that is an MVC Controller, digs up the methods. Methods decorated with the MvcMenuItemAttribute get plucked and added to the output list. Again, pretty simple. To make the structure hierarchical, a LINQ expression matches up all the items to their parent: public static void RegisterMenuItems(List<MvcMenuItemAttribute> items) { _MenuItems = items; _MenuItems.ForEach(i => i.ParentItem = items.FirstOrDefault(p => String.Equals(p.Link, i.ParentLink, StringComparison.InvariantCultureIgnoreCase))); } The _MenuItems is simply an internal list to keep things around for later rendering. Finally, to package the menu building for easy consumption: public static void RegisterMenuItems(Type mvcApplicationType) { RegisterMenuItems(ListMenuItems(Assembly.GetAssembly(mvcApplicationType))); } To bring this puppy home, a call in Global.asax.cs Application_Start() registers the menu. Notice the ugliness of reflection is tucked away from the innocent developer. All they have to do is call the RegisterMenuItems() and pass in the type of the application. When you use the new project template, global.asax declares a class public class MvcApplication : HttpApplication and that is why the Register call passes in that type. protected void Application_Start() { AreaRegistration.RegisterAllAreas(); RegisterRoutes(RouteTable.Routes);   MvcMenu.RegisterMenuItems(typeof(MvcApplication)); }   What else is left to do? Oh, right, render! public static void ShowMenu(this TextWriter output) { var writer = new HtmlTextWriter(output);   renderHierarchy(writer, _MenuItems, null); }   public static void ShowBreadCrumb(this TextWriter output, Uri currentUri) { var writer = new HtmlTextWriter(output); string currentLink = "/" + currentUri.GetComponents(UriComponents.Path, UriFormat.Unescaped);   var menuItem = _MenuItems.FirstOrDefault(m => m.Link.Equals(currentLink, StringComparison.CurrentCultureIgnoreCase)); if (menuItem != null) { renderBreadCrumb(writer, _MenuItems, menuItem); } }   private static void renderBreadCrumb(HtmlTextWriter writer, List<MvcMenuItemAttribute> menuItems, MvcMenuItemAttribute current) { if (current == null) { return; } var parent = current.ParentItem; renderBreadCrumb(writer, menuItems, parent); writer.Write(current.MenuText); writer.Write(" / ");   }     static void renderHierarchy(HtmlTextWriter writer, List<MvcMenuItemAttribute> hierarchy, MvcMenuItemAttribute root) { if (!hierarchy.Any(i => i.ParentItem == root)) return;   writer.RenderBeginTag(HtmlTextWriterTag.Ul); foreach (var current in hierarchy.Where(element => element.ParentItem == root).OrderBy(i => i.Order)) { if (ItemFilter == null || ItemFilter(current)) {   writer.RenderBeginTag(HtmlTextWriterTag.Li); writer.AddAttribute(HtmlTextWriterAttribute.Href, current.Link); writer.AddAttribute(HtmlTextWriterAttribute.Alt, current.MenuText); writer.RenderBeginTag(HtmlTextWriterTag.A); writer.WriteEncodedText(current.MenuText); writer.RenderEndTag(); // link renderHierarchy(writer, hierarchy, current); writer.RenderEndTag(); // li } } writer.RenderEndTag(); // ul } The ShowMenu method renders the menu out to the provided TextWriter. In previous posts I've discussed my partiality to using well debugged, time test HtmlTextWriter to render HTML rather than writing out angled brackets by hand. In addition, writing out using the actual writer on the actual stream rather than generating string and byte intermediaries (yes, StringBuilder being no exception) disturbs me. To carry out the rendering of an hierarchical menu, the recursive renderHierarchy() is used. You may notice that an ItemFilter is called before rendering each item. I figured that at some point one might want to exclude certain items from the menu based on security role or context or something. That delegate is the hook for such future feature. To carry out rendering of a breadcrumb recursion is used again, this time simply to unwind the parent hierarchy from the leaf node, then rendering on the return from the recursion rather than as we go along deeper. I guess I was stuck in LISP that day.. recursion is fun though.   Now all that is left is some usage! Open your Site.Master or wherever you'd like to place a menu or breadcrumb, and plant one of these calls: <% MvcMenu.ShowBreadCrumb(this.Writer, Request.Url); %> to show a breadcrumb trail (notice lack of "=" after <% and the semicolon). <% MvcMenu.ShowMenu(Writer); %> to show the menu.   As mentioned before, the HTML output is nested <UL> <LI> tags, which should make it easy to style using abundant CSS to produce anything from static horizontal or vertical to dynamic drop-downs.   This has been quite a fun little implementation and I was pleased that the code size remained low. The main crux was figuring out how to pass parent information from the attribute to the hierarchy builder because attributes have restricted parameter types. Once I settled on that implementation, the rest falls into place quite easily.

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• Microsoft Channel 9 Interviews Mei Liang to Introduce Sample Browser Extension for Visual Studio 2012 and 2010

  - by Jialiang

  This morning, Microsoft Channel 9 interviewed Mei Liang - Group Manager of Microsoft All-In-One Code Framework - to introduce the newest Sample Browser extension for Visual Studio 2012 &2010.   This extension provides a way for developers to search and download more than 4500 code samples from within Visual Studio, including over 700 Windows 8 samples and more than 1000 All-In-One Code Framework customer-driven code samples. Mei shows us not only the extension, but also the standalone version of the Sample Browser.   http://channel9.msdn.com/Shows/Visual-Studio-Toolbox/Sample-Browser-Visual-Studio-Extension   Microsoft All-In-One Code Framework, working in close partnership with the Visual Studio product team and MSDN Samples Gallery, developed the Sample Browser extension for both Visual Studio 2012 and Visual Studio 2010.  As an effort to evolve the code sample use experience and improve developers' productivity, the Sample Browser allows programmers to search, download and open over 4500 code samples from within Visual Studio with just a few simple clicks.  If no existing code sample can meet the needs, developers can even request a code sample easily from Microsoft thanks to the free “Sample Request Service” offered by Microsoft All-In-One Code Framework.  Through innovations, the teams hope to put the power of tens of thousands of code samples at developers’ fingertips. In short 3 months, the Sample Browser Visual Studio Extension has been installed by 100K global users.  It is also selected as one of the six most highly regarded and commonly used tools for Visual Studio that will make your programming experience feel like never before.   Got to love the All-In-One Code Framework team! You guys know this is THE go to source for code samples. Get this extension and you'll never need to leave VS2012 (well except for bathroom trips, but that's TMI anyway... ;) Read More... From: Greg Duncan (Author of CoolThingOfTheDay) 9/6/2011 12:00 AM The one software design pattern that I have used in just about every application I’ve written is “cut-and-paste,” so the new “Sample Browser” – read sample as a noun not an adjective – is a great boon to my productivity. Read More... From: Jim O'Neil (Microsoft Developer Evangelist) 9/28/2011 12:00 AM Install: http://aka.ms/samplebrowservsx Microsoft All-In-One Code Framework also offers the standalone version of Sample Browser.   The standalone version is particularly useful to Visual Studio Express edition or Visual Studio 2008 users, who cannot install the Sample Browser Visual Studio extension.   From Grassroots’ Passion for Developers to the Innovation of Sample Browser This Sample Browser has come a very long way improving the code sample use experience.  The history can be traced back to a grass-root innovation three years ago.   In early 2009, a few MSDN forum support engineers observed that lots of developers were struggling to work in Visual Studio without adequate code samples. Programming tasks seem harder than they should be when you only read through the documentation.  Just a couple of lines of sample code could answer a lot of questions.   They had a brilliant idea: What if we produce code samples based on developers’ frequently asked programming tasks in forums, social networks and support incidents, and then aggregate all our sample code in a one-stop library to benefit developers?  And what if developers can request code samples directly from Microsoft, free of charge?  This small group of grassroots at Microsoft devoted their nights and weekends to prototyping such a customer-driven code sample library.  This simple idea eventually turned into “Microsoft All-In-One Code Framework”, aka. OneCode.  With the support from more and more passionate developers at Microsoft and the leaders in the Community and Online Support team and Microsoft Commercial Technical Services (CTS), the idea has become a continually growing library with over 1000 customer-driven code samples covering almost all Microsoft development technologies.  These code samples originated from developers’ common pains and needs should be able to help many developers.  However, if developers cannot easily discover the code samples, the effort would still be in vain.  So in early 2010, the team started the idea of Sample Browser to ease the discovery and access of these samples.  In just two months, the first version of Sample Browser was finished and released by a passionate developer.  It was a very simple application, only supporting the basic sample offline search.  Users had to download the whole 100MB sample package containing all samples first, and run the Sample Browser to search locally.   Though developers could not search and download samples on-demand, this simple application laid a solid foundation for the team’s continuous innovations of Sample Browsing experience. In 2011, MSDN Samples Gallery had a big refresh.  The online sample experience was brought to a new level thanks to its PM Steven Wilssens and the gallery team’s effort.  Microsoft All-In-One Code Framework Team saw the opportunity to realize the “on-demand” sample search and download feature with the new gallery.  The two teams formed a strong partnership to upload all the customer-driven code samples to MSDN Samples Gallery, and released the new version of Sample Browser to support “on-demand” sample downloading in April, 2011.  Mei Liang, the Group Manager of Microsoft All-In-One Code Framework, was interviewed by Channel 9 to demo the Sample Browser.  Customers love the effort and the innovation!!  This can be clearly seen from the user comments in the publishing page.   It was very encouraging to the team of All-In-One Code Framework. The team continues innovating and evolving the Sample Browser.  They found the Visual Studio product team this time, and integrated the Sample Browsing experience into the latest Visual Studio 2012.  The newly released Sample Browser Visual Studio extension makes good use of Visual Studio 2012 IDE such as the new Quick Launch bar, the code editor, the toolbar and menus to offer easy access to thousands of code samples from within the development environment.   The Visual Studio Senior Program Manager Lead - Anthony Cangialosi, the Program Manager - Murali Krishna Hosabettu Kamalesha, the MSDN Samples Gallery PM – Steven Wilssens, and the Visual Studio Senior Escalation Engineer - Ed Dore shared lots of insightful suggestions with the team.  Thanks to the brilliant cross-group collaboration inside Microsoft, tens of new features including “Local Language Support” and “Favorite Samples”, as well as a face-lifted user interface, were added to further enhance the user experience. Since the new Sample Browser Visual Studio extension was released, it has received over 100 thousand downloads and five-star ratings.  A customer told the team that he officially falls in LOVE with Microsoft All-In-One Code Framework.   The Sample Browser Innovation for Developers Never Stops! The teams would never stop improving the Sample Browser for developers’ easier lives.   The Microsoft All-In-One Code Framework, Visual Studio and MSDN Samples Gallery teams are working closely to develop the next version of Sample Browser.  Here are the key functions in development or in discussion.  We hope to learn your feedback of the effort.  You can submit your suggestions to the official Visual Studio UserVoice site.  We look forward to hearing from you! 1) Offline Sample Search This is one of the top feature requests that we have received for Sample Browser.   The Sample Browser will support the offline search mode so that developers can search downloaded code samples when they do not have internet access.  This is particularly useful to developers in Enterprises with strict proxy settings. 2) Code Snippet Support and Visual Studio Editor Integration Today, the Sample Browser supports downloading and opening sample project.   However, when developers are searching for code samples, a better user experience would be to see the code snippets in the search result first.  Developers can quickly decide if the code snippet is relevant.   They can also drag and drop the code snippet into the Visual Studio Editor to solve some simple programming tasks.  If developers want to learn more about the sample, they can then choose to download the sample project and open it in Visual Studio. 3) Enterprise Sample Sharing and Searching Large enterprises have many code samples for their own internal tools and APIs that are not appropriate to be shared publicly in MSDN Samples Gallery.   In that case, today’s Sample Browser and MSDN Samples Gallery cannot help these Enterprise developers.  The idea is to create a Code Sample Repository in TFS, and provide an additional Visual Studio extension for Enterprise developers to quickly share code samples to TFS.  The Sample Browser can be configured to connect to the TFS Code Sample Repository to search for and download code samples.  This would potentially enable the Enterprise developers to be more productive. 4) Windows Store Sample Browser With the upcoming release of Windows RT and Microsoft Surface, developers are facing a completely new world of application platform.   Not like laptop, people would often use Microsoft Surface in commute and in travel.  Internet may not be available.  Today’s Visual Studio cannot be installed and run on Windows RT, however, our enthusiastic developers would hope to spend every minute on code.  They love code!   The idea is to create a Windows Store version of Sample Browser. Search and download samples from the online Samples Gallery when the user has internet access. Browse the sample code files and learn the sample documentation of downloaded samples with or without internet access.   In addition to the "browse” function, the Sample Browser could further support “bookmark”, “learning notes”, “code review”, and “quick social sharing". Make full use of the new touch and Windows Store App UI to give developers a new “relaxing” code browsing and learning experience, anytime, anywhere. With Windows Store Sample Browser, developers can enjoy A new relaxing and enjoyable experience for developers to learn code samples You do not have to sit in front of desk and formally open Visual Studio to read code samples.  Many developers get sub-health due to staying in front of desk for a very long time.  With Windows RT, Microsoft Surface and this Windows Store Sample Browser combining with the online MSDN Samples Gallery, developers can sit in a sofa, relaxingly hold the tablet and enjoy to learn their beloved sample code with detailed documentation. Anytime, anywhere Whether you have internet access or not, whether you are at home, in office, or in commute/airplane, developers can always easily access and browse the sample code. Lightweight and fast Particularly for learning a small sample project, the Windows Store Sample Browser would be more lightweight and faster to open and browse the sample code. Please submit your feedback and suggestion to Visual Studio UserVoice.  We look forward to hearing from you and deliver a better and better sample use experience.  Happy Coding!   Special Thanks to People working behind the latest release of Sample Browser Visual Studio Extension and the great partnerships!

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• Uganda .NET Usergroup meeting (February 2010)

  - by Malisa L. Ncube

  We had a very interesting .NET meeting in which i gave a short presentation on the new features of .NET 4.0 and Visual Studio 2010. The main presentation came from Jake Markhus @jmarkhus who talked about NHibernate (http://nhforge.org).   The membership for the group is growing each time we meet and its very encouraging. Some employers found candidates within our group for hiring, and this has resulted in a mutual benefit between the employers and job-seekers – really cool stuff.   Jake above giving us the soup and nuts of NHibernate. We were very excited since a number companies decided to support us in many ways. Some members won the licenses for Telerik Suite (http://www.telerik.com) while Intellisense LTD (http://www.intellisense.co.ug) agreed to sponsor us on domain registration and hosting of the community site. Jake announced on the possibility of having DevExpress (http://www.devexpress.com) sponsor us on 2 licenses of CodeRush http://www.devexpress.com/coderush which would be won in the next meeting raffle. I (@malisancube) would like to thank all the companies and individuals who have decided to sponsor us as a community of developers. We appreciate your support very much. You can download the presentations here Jan 2010 “VS2010 and NET 4.0” by Malisa Ncube. Feb 2010 “Using NHibernate” by Jake Markhus   Technorati Tags: Uganda .NET Usergroup,.NET 4.0,Community,NHibernate

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• dpkg: error: parsing file '/var/lib/dpkg/status' near line 6449

  - by mpole

  Good evening. This problem occured when trying to update using the update manager. A problem occured so I cleared all the cache and tried to update once again this time in terminal, and it spat out: dpkg: error: parsing file '/var/lib/dpkg/status' near line 6449 missing package name After opening up 'status' with gedit and going to line 6449, I found that nothing was on that line but the following was before and after it. This package contains the Mono System.Configuration library for CLI 4.0. Original-Maintainer: Debian Mono Group <[email protected])oth.debian.org> Homepage: http://www.mono-project.com/ <<<<---- LINE 6449 Package: bzip2 Status: install ok installed Priority: optional Section: utils Installed-Size: 160 Maintainer: Ubuntu Developers <[email protected]> <<<<--- LINE 6449 is obviously not on the file, but I can't see whats wrong here? anybody have an idea? Thanks! Edit: I have tried running: sudo apt-get install --fix-missing sudo dpkg --clear-avail But no good...

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• This is the End of Business as Usual...

  - by Michael Snow

  This week, we'll be hosting our last Social Business Thought Leader Series Webcast for 2012. Our featured guest this week will be Brian Solis of Altimeter Group. As we've been going through the preparations for Brian's webcast, it became very clear that an hour's time is barely scraping the surface of the depth of Brian's insights and analysis. Accordingly, in the spirit of sharing Brian's perspective for all of our readers, we'll be featuring guest posts all this week pulled from Brian's larger collection of blog postings on his own website. If you like what you've read here this week, we highly recommend digging deeper into his tome of wisdom. Guest Post by Brian Solis, Analyst, Altimeter Group as originally featured on his site with the minor change of the video addition at the beginning of the post. This is the End of Business as Usual and the Beginning of a New Era of Relevance - Brian Solis, Principal Analyst, Altimeter Group The Times They Are A-Changin’ Come gather ’round people Wherever you roam And admit that the waters Around you have grown And accept it that soon You’ll be drenched to the bone If your time to you Is worth savin’ Then you better start swimmin’ Or you’ll sink like a stone For the times they are a-changin’. - Bob Dylan I’m sure you are wondering why I chose lyrics to open this article. If you skimmed through them, stop here for a moment. Go back through the Dylan’s words and take your time. Carefully read, and feel, what it is he’s saying and savor the moment to connect the meaning of his words to the challenges you face today. His message is as important and true today as it was when they were first written in 1964. The tide is indeed once again turning. And even though the 60s now live in the history books, right here, right now, Dylan is telling us once again that this is our time to not only sink or swim, but to do something amazing. This is your time. This is our time. But, these times are different and what comes next is difficult to grasp. How people communicate. How people learn and share. How people make decisions. Everything is different now. Think about this…you’re reading this article because it was sent to you via email. Yet more people spend their online time in social networks than they do in email. Duh. According to Nielsen, of the total time spent online 22.5% are connecting and communicating in social networks. To put that in perspective, the time spent in the likes of Facebook, Twitter, and Youtube is greater than online gaming at 9.8%, email at 7.6% and search at 4%. Imagine for a moment if you and I were connected to one another in Facebook, which just so happens to be the largest social network in the world. How big? Well, Facebook is the size today of the entire Internet in 2004. There are over 1 billion people friending, Liking, commenting, sharing, and engaging in Facebook…that’s roughly 12% of the world’s population. Twitter has over 200 million users. Ever hear of tumblr? More time is spent on this popular microblogging community than Twitter. The point is that the landscape for communication and all that’s affected by human interaction is profoundly different than how you and I learned, shared or talked to one another yesterday. This transformation is only becoming more pervasive and, it’s not going back. Survival of the Fitting But social media is just one of the channels we can use to reach people. I must be honest. I’m as much a part of tomorrow as I am of yesteryear. It’s why I spend all of my time researching the evolution of media and its impact on business and culture. Because of you, I share everything I learn in newsletters, emails, blogs, Youtube videos, and also traditional books. I’m dedicated to helping everyone not only understand, but grasp the change that’s before you. Technologies such as social, mobile, virtual, augmented, et al compel us adapt our story and value proposition and extend our reach to be part of communities we don’t realize exist. The people who will keep you in business or running tomorrow are the very people you’re not reaching today. Before you continue to read on, allow me to clarify my point of view. My inspiration for writing this is to help you augment, not necessarily replace, the programs you’re running today. We must still reach those whom matter to us in the ways they prefer to be engaged. To reach what I call the connected consumer of Geneeration-C we must too reach them in the ways they wish to be engaged. And in all of my work, how they connect, talk to one another, influence others, and make decisions are not at all like the traditional consumers of the past. Nor are they merely the kids…the Millennial. Connected consumers are representative across every age group and demographic. As you can see, use of social networks, media sharing sites, microblogs, blogs, etc. equally span across Gen Y, Gen X, and Baby Boomers. The DNA of connected customers is indiscriminant of age or any other demographic for that matter. This is more about psychographics, the linkage of people through common interests (than it is their age, gender, education, nationality or level of income. Once someone is introduced to the marvels of connectedness, the sensation becomes a contagion. It touches and affects everyone. And, that’s why this isn’t going anywhere but normalcy. Social networking isn’t just about telling people what you’re doing. Nor is it just about generic, meaningless conversation. Today’s connected consumer is incredibly influential. They’re connected to hundreds and even thousands of other like-minded people. What they experiences, what they support, it’s shared throughout these networks and as information travels, it shapes and steers impressions, decisions, and experiences of others. For example, if we revisit the Nielsen research, we get an idea of just how big this is becoming. 75% spend heavily on music. How does that translate to the arts? I’d imagine the number is equally impressive. If 53% follow their favorite brand or organization, imagine what’s possible. Just like this email list that connects us, connections in social networks are powerful. The difference is however, that people spend more time in social networks than they do in email. Everything begins with an understanding of the “5 W’s and H.E.” – Who, What, When, Where, How, and to What Extent? The data that comes back tells you which networks are important to the people you’re trying to reach, how they connect, what they share, what they value, and how to connect with them. From there, your next steps are to create a community strategy that extends your mission, vision, and value and it align it with the interests, behavior, and values of those you wish to reach and galvanize. To help, I’ve prepared an action list for you, otherwise known as the 10 Steps Toward New Relevance: 1. Answer why you should engage in social networks and why anyone would want to engage with you 2. Observe what brings them together and define how you can add value to the conversation 3. Identify the influential voices that matter to your world, recognize what’s important to them, and find a way to start a dialogue that can foster a meaningful and mutually beneficial relationship 4. Study the best practices of not just organizations like yours, but also those who are successfully reaching the type of people you’re trying to reach – it’s benching marking against competitors and benchmarking against undefined opportunities 5. Translate all you’ve learned into a convincing presentation written to demonstrate tangible opportunity to your executive board, make the case through numbers, trends, data, insights – understanding they have no idea what’s going on out there and you are both the scout and the navigator (start with a recommended pilot so everyone can learn together) 6. Listen to what they’re saying and develop a process to learn from activity and adapt to interests and steer engagement based on insights 7. Recognize how they use social media and innovate based on what you observe to captivate their attention 8. Align your objectives with their objectives. If you’re unsure of what they’re looking for…ask 9. Invest in the development of content, engagement 10. Build a community, invest in values, spark meaningful dialogue, and offer tangible value…the kind of value they can’t get anywhere else. Take advantage of the medium and the opportunity! The reality is that we live and compete in a perpetual era of Digital Darwinism, the evolution of consumer behavior when society and technology evolve faster than our ability to adapt. This is why it’s our time to alter our course. We must connect with those who are defining the future of engagement, commerce, business, and how the arts are appreciated and supported. Even though it is the end of business as usual, it is the beginning of a new age of opportunity. The consumer revolution is already underway, and the question is: How do you better understand the role you play in this production as a connected or social consumer as well as business professional? Again, this is your time to define a new era of engagement and relevance. Originally written for The National Arts Marketing Project Connect with Brian via: Twitter | LinkedIn | Facebook | Google+ --- Note from Michael: If you really like this post above - check out Brian's TEDTalk and his thought process for preparing it in this post: 12.00 Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-family:"Calibri","sans-serif"; mso-bidi-font-family:"Times New Roman";} http://www.briansolis.com/2012/10/tedtalk-reinventing-consumer-capitalism-screw-business-as-usual/

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• Passing elapsed time to the update function from the game loop

  - by Sri Harsha Chilakapati

  I want to pass the time elapsed to the update() method as this would make easy to implement the animations and time related concepts. Here's my game-loop. public void gameLoop(){ boolean running = true; long gameTime = getCurrentTime(); long elapsedTime = 0; long lastUpdateTime = 0; int loops; while (running){ loops = 0; while(getCurrentTime()>gameTime && loops<Global.MAX_FRAMESKIP){ elapsedTime = getCurrentTime() - lastUpdateTime; lastUpdateTime = getCurrentTime(); update(elapsedTime); gameTime += SKIP_STEPS; loops++; } displayGame(); } } getCurrentTime() method public long getCurrentTime(){ return (System.nanoTime()/1000000); } update() method long time = 0; public void update(long elapsedTime){ time += elapsedTime; if (time>=1000){ System.out.println("A second elapsed"); time -= 1000; } } But this is printing the message for 3 seconds. Thanks.

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• The Retail Week Conference 2012 - Interview with Paul Dickson

  - by user801960

  Recently we attended the Retail Week Conference at the Hilton London Metropole Hotel in London. The conference proves to be an inspirational meeting of retail minds and the insight gained from both the speakers and the other delegates is invaluable. In particular we enjoyed hearing from Charlie Mayfield, Chairman at John Lewis Partnership, about understanding how the consumer is viewing the ever changing world of retail; a session on how to encourage brand-loyal multichannel activities from Robin Terrell of House of Fraser with Alan White of the N Brown Group, Vince Russell from The Cloud and Lucy Neville-Rolfe from Tesco; and a fascinating session from Tim Steiner, Chief Executive of Ocado, about how the business makes it as easy as possible for consumers to shop on their various platforms, which included some surprising usage statistics. Oracle's own Vice President of Retail, Paul Dickson, also held a session with Richard Pennycook, Group Finance Director at Morrisons, about the role of technology in accelerating and supporting the business strategy. Morrisons' 'Evolve' programme takes a litte-and-often approach to updating its technology infrastructure to spread cost and keep the adoption process gentle for staff, and the session explored how the process works and how Oracle's technology underpins the programme to optimise their operations using actionable insight. We had a quick chat with Paul Dickson at the session to get his thoughts on the programme - the video is below. We also filmed the whole presentation, so keep checking back on this blog if you're interested in seeing it.

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• Performance Optimization &ndash; It Is Faster When You Can Measure It

  - by Alois Kraus

  Performance optimization in bigger systems is hard because the measured numbers can vary greatly depending on the measurement method of your choice. To measure execution timing of specific methods in your application you usually use Time Measurement Method Potential Pitfalls Stopwatch Most accurate method on recent processors. Internally it uses the RDTSC instruction. Since the counter is processor specific you can get greatly different values when your thread is scheduled to another core or the core goes into a power saving mode. But things do change luckily: Intel's Designer's vol3b, section 16.11.1 "16.11.1 Invariant TSC The time stamp counter in newer processors may support an enhancement, referred to as invariant TSC. Processor's support for invariant TSC is indicated by CPUID.80000007H:EDX[8]. The invariant TSC will run at a constant rate in all ACPI P-, C-. and T-states. This is the architectural behavior moving forward. On processors with invariant TSC support, the OS may use the TSC for wall clock timer services (instead of ACPI or HPET timers). TSC reads are much more efficient and do not incur the overhead associated with a ring transition or access to a platform resource." DateTime.Now Good but it has only a resolution of 16ms which can be not enough if you want more accuracy.   Reporting Method Potential Pitfalls Console.WriteLine Ok if not called too often. Debug.Print Are you really measuring performance with Debug Builds? Shame on you. Trace.WriteLine Better but you need to plug in some good output listener like a trace file. But be aware that the first time you call this method it will read your app.config and deserialize your system.diagnostics section which does also take time.   In general it is a good idea to use some tracing library which does measure the timing for you and you only need to decorate some methods with tracing so you can later verify if something has changed for the better or worse. In my previous article I did compare measuring performance with quantum mechanics. This analogy does work surprising well. When you measure a quantum system there is a lower limit how accurately you can measure something. The Heisenberg uncertainty relation does tell us that you cannot measure of a quantum system the impulse and location of a particle at the same time with infinite accuracy. For programmers the two variables are execution time and memory allocations. If you try to measure the timings of all methods in your application you will need to store them somewhere. The fastest storage space besides the CPU cache is the memory. But if your timing values do consume all available memory there is no memory left for the actual application to run. On the other hand if you try to record all memory allocations of your application you will also need to store the data somewhere. This will cost you memory and execution time. These constraints are always there and regardless how good the marketing of tool vendors for performance and memory profilers are: Any measurement will disturb the system in a non predictable way. Commercial tool vendors will tell you they do calculate this overhead and subtract it from the measured values to give you the most accurate values but in reality it is not entirely true. After falling into the trap to trust the profiler timings several times I have got into the habit to Measure with a profiler to get an idea where potential bottlenecks are. Measure again with tracing only the specific methods to check if this method is really worth optimizing. Optimize it Measure again. Be surprised that your optimization has made things worse. Think harder Implement something that really works. Measure again Finished! - Or look for the next bottleneck. Recently I have looked into issues with serialization performance. For serialization DataContractSerializer was used and I was not sure if XML is really the most optimal wire format. After looking around I have found protobuf-net which uses Googles Protocol Buffer format which is a compact binary serialization format. What is good for Google should be good for us. A small sample app to check out performance was a matter of minutes: using ProtoBuf; using System; using System.Diagnostics; using System.IO; using System.Reflection; using System.Runtime.Serialization; [DataContract, Serializable] class Data { [DataMember(Order=1)] public int IntValue { get; set; } [DataMember(Order = 2)] public string StringValue { get; set; } [DataMember(Order = 3)] public bool IsActivated { get; set; } [DataMember(Order = 4)] public BindingFlags Flags { get; set; } } class Program { static MemoryStream _Stream = new MemoryStream(); static MemoryStream Stream { get { _Stream.Position = 0; _Stream.SetLength(0); return _Stream; } } static void Main(string[] args) { DataContractSerializer ser = new DataContractSerializer(typeof(Data)); Data data = new Data { IntValue = 100, IsActivated = true, StringValue = "Hi this is a small string value to check if serialization does work as expected" }; var sw = Stopwatch.StartNew(); int Runs = 1000 * 1000; for (int i = 0; i < Runs; i++) { //ser.WriteObject(Stream, data); Serializer.Serialize<Data>(Stream, data); } sw.Stop(); Console.WriteLine("Did take {0:N0}ms for {1:N0} objects", sw.Elapsed.TotalMilliseconds, Runs); Console.ReadLine(); } } The results are indeed promising: Serializer Time in ms N objects protobuf-net   807 1000000 DataContract 4402 1000000 Nearly a factor 5 faster and a much more compact wire format. Lets use it! After switching over to protbuf-net the transfered wire data has dropped by a factor two (good) and the performance has worsened by nearly a factor two. How is that possible? We have measured it? Protobuf-net is much faster! As it turns out protobuf-net is faster but it has a cost: For the first time a type is de/serialized it does use some very smart code-gen which does not come for free. Lets try to measure this one by setting of our performance test app the Runs value not to one million but to 1. Serializer Time in ms N objects protobuf-net 85 1 DataContract 24 1 The code-gen overhead is significant and can take up to 200ms for more complex types. The break even point where the code-gen cost is amortized by its faster serialization performance is (assuming small objects) somewhere between 20.000-40.000 serialized objects. As it turned out my specific scenario involved about 100 types and 1000 serializations in total. That explains why the good old DataContractSerializer is not so easy to take out of business. The final approach I ended up was to reduce the number of types and to serialize primitive types via BinaryWriter directly which turned out to be a pretty good alternative. It sounded good until I measured again and found that my optimizations so far do not help much. After looking more deeper at the profiling data I did found that one of the 1000 calls did take 50% of the time. So how do I find out which call it was? Normal profilers do fail short at this discipline. A (totally undeserved) relatively unknown profiler is SpeedTrace which does unlike normal profilers create traces of your applications by instrumenting your IL code at runtime. This way you can look at the full call stack of the one slow serializer call to find out if this stack was something special. Unfortunately the call stack showed nothing special. But luckily I have my own tracing as well and I could see that the slow serializer call did happen during the serialization of a bool value. When you encounter after much analysis something unreasonable you cannot explain it then the chances are good that your thread was suspended by the garbage collector. If there is a problem with excessive GCs remains to be investigated but so far the serialization performance seems to be mostly ok.  When you do profile a complex system with many interconnected processes you can never be sure that the timings you just did measure are accurate at all. Some process might be hitting the disc slowing things down for all other processes for some seconds as well. There is a big difference between warm and cold startup. If you restart all processes you can basically forget the first run because of the OS disc cache, JIT and GCs make the measured timings very flexible. When you are in need of a random number generator you should measure cold startup times of a sufficiently complex system. After the first run you can try again getting different and much lower numbers. Now try again at least two times to get some feeling how stable the numbers are. Oh and try to do the same thing the next day. It might be that the bottleneck you found yesterday is gone today. Thanks to GC and other random stuff it can become pretty hard to find stuff worth optimizing if no big bottlenecks except bloatloads of code are left anymore. When I have found a spot worth optimizing I do make the code changes and do measure again to check if something has changed. If it has got slower and I am certain that my change should have made it faster I can blame the GC again. The thing is that if you optimize stuff and you allocate less objects the GC times will shift to some other location. If you are unlucky it will make your faster working code slower because you see now GCs at times where none were before. This is where the stuff does get really tricky. A safe escape hatch is to create a repro of the slow code in an isolated application so you can change things fast in a reliable manner. Then the normal profilers do also start working again. As Vance Morrison does point out it is much more complex to profile a system against the wall clock compared to optimize for CPU time. The reason is that for wall clock time analysis you need to understand how your system does work and which threads (if you have not one but perhaps 20) are causing a visible delay to the end user and which threads can wait a long time without affecting the user experience at all. Next time: Commercial profiler shootout.

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• How do you deal with translating theory into practice?

  - by Mr. Shickadance

  Hello all! Being a computer scientist in a research field I am often tasked with working alongside professionals outside of the software domain (think math people, electrical engineer etc), and then translating their theories and ideas into real-world implementations. I often find it difficult when they present a theoretical problem which appears to be somewhat disconnected from reality. I am not saying that the theory is bogus, only that it is difficult to translate into real-world situations. For example, recently I have been working with software defined radios. We are exploring many different areas, but often the math specialists in my group would present a problem which is heavily grounded in theory (signal processing, physics, whatever). I often struggle at times where it is hard to draw direct parallels between the theory and the real-world implementation that I need to develop. Say we are working on an energy detector, the theory person in my group would say "you need to measure the noise variance with no signal present." This leads me to think "how the hell do I isolate noise from a signal in reality?" There are many examples, but I hope you see where I am going. So, my question is how does one deal with implementation of theoretical concepts when the theory seems detached from reality? Or at least when the connections are not so clear. Or perhaps, the person with the 'theory' may be ignorant of real restrictions? Note: I found this to be a hard question to ask - hopefully you are following me. If you have suggestions on how I could improve it, by all means let me know! Thanks for looking! EDIT: To be a bit more clear, I understand in situations like this that I must learn that specific domain myself to an extent (i.e. signal processing), but I am more concerned with when those theoretical concepts do not appear to be as grounded in practice as one would like.

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• SharePoint Q&A With the MVP Gang

  - by Bil Simser

  Interested in getting some first hand knowledge about SharePoint and all of it’s quirks, oddities, and secrets? We’re hosting not one, but *two* SharePoint Q&A sessions with the MVP crowd. Here’s the official blurb: Do you have tough technical questions regarding SharePoint for which you're seeking answers? Do you want to tap into the deep knowledge of the talented Microsoft Most Valuable Professionals? The SharePoint MVPs are the same people you see in the technical community as authors, speakers, user group leaders and answerers in the MSDN forums. By popular demand, we have brought these experts together as a collective group to answer your questions live. So please join us and bring on the questions! This chat will cover WSS, MOSS and the SharePoint 2010. Topics include setup and administration, design, development and general questions. Here’s a rundown of the expected guests for the chats: Agnes Molnar, Andrew Connell, Asif Rehmani, Becky Bertram, Me, Bryan Phillips, Chris O'Brien, Clayton Cobb, Dan Attis, Darrin Bishop, David Mann, Gary Lapointe, John Ross, Mike Oryzak, Muhanad Omar, Paul Stork, Randy Drisgill, Rob Bogue, Rob Foster, Shane Young, Spence Harbar. Apologies for not linking to everyone’s blogs, I’m just not that ambitious tonight. Please note that not everyone listed here is guaranteed to make it to either chat and there may be additions/changes at the last minute so the names may change to protect the innocent. The chat sessions will be held April 27th, 2010 at 4PM (PST) and April 28th at 9AM (PST). You can find out more details about the chats here or click here to add the April 27th event to your calendar, or click here to add the April 28th event (assuming your calendar software supports ICS files). See you there!

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• 5 New Java Champions

  - by Tori Wieldt

  The Java Champions have nominated and accepted five new members to their group: Jonas Bonér, James Strachan, Rickard Oberg, Régina ten Bruggencate, and Clara Ko. Congratulations, and we look forward to hearing more from each of them!Jonas Bonér (Sweden) is a Java entrepreneur, programmer, teacher, speaker and author. He is an active contributor to the Open Source community; and most notably created the Akka Project, AspectWerkz Aspect-Oriented Programming (AOP) framework. James Strachan (UK) has more than 20 years experience in enterprise software development with a background in finance and middleware and is also committer on a number of open source projects, including Apache Karaf, Maven, Lift and Jersey.Rickard Oberg (Malaysia) has worked on several Open Source projects that involve JEE development, such as JBoss, XDoclet and WebWork. He has also been the principal architect of the SiteVision CMS/portal platform, where he used AOP as the foundation. Now he works for Jayway, developing the Qi4j framework and Composite Oriented Programming paradigm.Régina ten Bruggencate (Netherlands) is a senior Java developer for iProfs with 10-plus years of Java experience, mainly on enterprise applications. Régina is the current president of Duchess, and as such has the responsibility for the site and community. Duchess is a global organization for women in Java technology, currently with 350 members in over 50 countries.Clara Ko (Netherlands) is a freelance Java/J2EE professional living in Amsterdam. She has worked as a developer, architect, and project manager. She promotes the use of open source software and has led initiatives to adopt agile practices across multiple organizations. Clara is also co-founder of Duchess.The Java Champions are an exclusive group of passionate Java technology and community leaders who are community-nominated and selected under a project sponsored by Oracle. Java Champions get the opportunity to provide feedback, ideas, and direction that will help Oracle grow the Java Platform. This interchange may be in the form of technical discussions and/or community-building activities with Oracle's Java Development and Developer Program teams. Full bios and details about the champions are on http://java-champions.java.net/.

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• Making a Case For The Command Line

  - by Jesse Taber

  Originally posted on: http://geekswithblogs.net/GruffCode/archive/2013/06/30/making-a-case-for-the-command-line.aspxI have had an idea percolating in the back of my mind for over a year now that I’ve just recently started to implement. This idea relates to building out “internal tools” to ease the maintenance and on-going support of a software system. The system that I currently work on is (mostly) web-based, so we traditionally we have built these internal tools in the form of pages within the app that are only accessible by our developers and support personnel. These pages allow us to perform tasks within the system that, for one reason or another, we don’t want to let our end users perform (e.g. mass create/update/delete operations on data, flipping switches that turn paid modules of the system on or off, etc). When we try to build new tools like this we often struggle with the level of effort required to build them. Effort Required Creating a whole new page in an existing web application can be a fairly large undertaking. You need to create the page and ensure it will have a layout that is consistent with the other pages in the app. You need to decide what types of input controls need to go onto the page. You need to ensure that everything uses the same style as the rest of the site. You need to figure out what the text on the page should say. Then, when you figure out that you forgot about an input that should really be present you might have to go back and re-work the entire thing. Oh, and in addition to all of that, you still have to, you know, write the code that actually performs the task. Everything other than the code that performs the task at hand is just overhead. We don’t need a fancy date picker control in a nicely styled page for the vast majority of our internal tools. We don’t even really need a page, for that matter. We just need a way to issue a command to the application and have it, in turn, execute the code that we’ve written to accomplish a given task. All we really need is a simple console application! Plumbing Problems A former co-worker of mine, John Sonmez, always advocated the Unix philosophy for building internal tools: start with something that runs at the command line, and then build a UI on top of that if you need to. John’s idea has a lot of merit, and we tried building out some internal tools as simple Console applications. Unfortunately, this was often easier said that done. Doing a “File –> New Project” to build out a tool for a mature system can be pretty daunting because that new project is totally empty.  In our case, the web application code had a lot of of “plumbing” built in: it managed authentication and authorization, it handled database connection management for our multi-tenanted architecture, it managed all of the context that needs to follow a user around the application such as their timezone and regional/language settings. In addition, the configuration file for the web application  (a web.config in our case because this is an ASP .NET application) is large and would need to be reproduced into a similar configuration file for a Console application. While most of these problems are could be solved pretty easily with some refactoring of the codebase, building Console applications for internal tools still potentially suffers from one pretty big drawback: you’d have to execute them on a machine with network access to all of the needed resources. Obviously, our web servers can easily communicate the the database servers and can publish messages to our service bus, but the same is not true for all of our developer and support personnel workstations. We could have everyone run these tools remotely via RDP or SSH, but that’s a bit cumbersome and certainly a lot less convenient than having the tools built into the web application that is so easily accessible. Mix and Match So we need a way to build tools that are easily accessible via the web application but also don’t require the overhead of creating a user interface. This is where my idea comes into play: why not just build a command line interface into the web application? If it’s part of the web application we get all of the plumbing that comes along with that code, and we’re executing everything on the web servers which means we’ll have access to any external resources that we might need. Rather than having to incur the overhead of creating a brand new page for each tool that we want to build, we can create one new page that simply accepts a command in text form and executes it as a request on the web server. In this way, we can focus on writing the code to accomplish the task. If the tool ends up being heavily used, then (and only then) should we consider spending the time to build a better user experience around it. To be clear, I’m not trying to downplay the importance of building great user experiences into your system; we should all strive to provide the best UX possible to our end users. I’m only advocating this sort of bare-bones interface for internal consumption by the technical staff that builds and supports the software. This command line interface should be the “back end” to a highly polished and eye-pleasing public face. Implementation As I mentioned at the beginning of this post, this is an idea that I’ve had for awhile but have only recently started building out. I’ve outlined some general guidelines and design goals for this effort as follows: Text in, text out: In the interest of keeping things as simple as possible, I want this interface to be purely text-based. Users will submit commands as plain text, and the application will provide responses in plain text. Obviously this text will be “wrapped” within the context of HTTP requests and responses, but I don’t want to have to think about HTML or CSS when taking input from the user or displaying responses back to the user. Task-oriented code only: After building the initial “harness” for this interface, the only code that should need to be written to create a new internal tool should be code that is expressly needed to accomplish the task that the tool is intended to support. If we want to encourage and enable ourselves to build good tooling, we need to lower the barriers to entry as much as possible. Built-in documentation: One of the great things about most command line utilities is the ‘help’ switch that provides usage guidelines and details about the arguments that the utility accepts. Our web-based command line utility should allow us to build the documentation for these tools directly into the code of the tools themselves. I finally started trying to implement this idea when I heard about a fantastic open-source library called CLAP (Command Line Auto Parser) that lets me meet the guidelines outlined above. CLAP lets you define classes with public methods that can be easily invoked from the command line. Here’s a quick example of the code that would be needed to create a new tool to do something within your system: 1: public class CustomerTools 2: { 3: [Verb] 4: public void UpdateName(int customerId, string firstName, string lastName) 5: { 6: //invoke internal services/domain objects/hwatever to perform update 7: } 8: } This is just a regular class with a single public method (though you could have as many methods as you want). The method is decorated with the ‘Verb’ attribute that tells the CLAP library that it is a method that can be invoked from the command line. Here is how you would invoke that code: Parser.Run(args, new CustomerTools()); Note that ‘args’ is just a string[] that would normally be passed passed in from the static Main method of a Console application. Also, CLAP allows you to pass in multiple classes that define [Verb] methods so you can opt to organize the code that CLAP will invoke in any way that you like. You can invoke this code from a command line application like this: SomeExe UpdateName -customerId:123 -firstName:Jesse -lastName:Taber ‘SomeExe’ in this example just represents the name of .exe that is would be created from our Console application. CLAP then interprets the arguments passed in order to find the method that should be invoked and automatically parses out the parameters that need to be passed in. After a quick spike, I’ve found that invoking the ‘Parser’ class can be done from within the context of a web application just as easily as it can from within the ‘Main’ method entry point of a Console application. There are, however, a few sticking points that I’m working around: Splitting arguments into the ‘args’ array like the command line: When you invoke a standard .NET console application you get the arguments that were passed in by the user split into a handy array (this is the ‘args’ parameter referenced above). Generally speaking they get split by whitespace, but it’s also clever enough to handle things like ignoring whitespace in a phrase that is surrounded by quotes. We’ll need to re-create this logic within our web application so that we can give the ‘args’ value to CLAP just like a console application would. Providing a response to the user: If you were writing a console application, you might just use Console.WriteLine to provide responses to the user as to the progress and eventual outcome of the command. We can’t use Console.WriteLine within a web application, so I’ll need to find another way to provide feedback to the user. Preferably this approach would allow me to use the same handler classes from both a Console application and a web application, so some kind of strategy pattern will likely emerge from this effort. Submitting files: Often an internal tool needs to support doing some kind of operation in bulk, and the easiest way to submit the data needed to support the bulk operation is in a file. Getting the file uploaded and available to the CLAP handler classes will take a little bit of effort. Mimicking the console experience: This isn’t really a requirement so much as a “nice to have”. To start out, the command-line interface in the web application will probably be a single ‘textarea’ control with a button to submit the contents to a handler that will pass it along to CLAP to be parsed and run. I think it would be interesting to use some javascript and CSS trickery to change that page into something with more of a “shell” interface look and feel. I’ll be blogging more about this effort in the future and will include some code snippets (or maybe even a full blown example app) as I progress. I also think that I’ll probably end up either submitting some pull requests to the CLAP project or possibly forking/wrapping it into a more web-friendly package and open sourcing that.

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• Subaru CIO wins SIM Leadership Award

  - by tony.berk

  Congratulations to Brian Simmermon, CIO at Subaru of America, Inc., for winning the Society for Information Management's (SIM) fifth annual SIM Leadership Award. Simmermon joined Subaru of America in 2005 as Chief Information Officer. Simmermon then performed a company-wide technology assessment and determined that the business ran a large collection of applications, many of which duplicated functionality. Establishing the mantra, "Simplicity, Flexibility, and Cost Effectiveness", he reduced the total number of applications, moved to a small core set of systems - including Oracle and Siebel. Tom Doll, COO for Subaru of America said, "We are very pleased Brian has been recognized. He has consistently shown vision and leadership and under his leadership, our technology group's innovations have helped our sales to grow to record levels, regardless of the economic circumstances." Simmermon's technology group's aggressive business deliverables have helped Subaru to become one of the most successful brands in the US with the brand reaching record sales in both 2009 and 2010. Click here to read the full press release. Click here to learn about Subaru's success with Oracle products. Congratulations Brian!

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• Is It Possible To Recover A Partial LVM Logical Volume?

  - by Terry Wang

  Background It is an Ubuntu 12.04 VirtualBox VM with 5 virtual HDDs (VDI), NOTE this is just a test VM, so not well planned ahead: ubuntu.vdi for / (/dev/mapper/ubuntu-root AKA /dev/ubuntu/root) and /home (/dev/mapper/ubuntu-home) weblogic.vdi - /dev/sdb (mounted on /bea for weblogic and other stuff) btrfs1.vdi - /dev/sdc (part of btrfs -m raid1 -d raid1 configuration) btrfs2.vdi - /dev/sdd (part of btrfs -m raid1 -d raid1 configuration) more.vdi - /dev/sde (added this virtual HDD because / ran out of inodes and it wasn't easy to figure out what to delete so as to free up inodes, so I just added the new virtual HDD, created PV, added it to existing volume group ubuntu, grew the root logical volume to work around the inode issue -_-) What happened? Last Friday, before finishing up I wanted to free up some disk space on that box, for some reason I thought the more.vdi was useless and tried to detach it from the VM, I then clicked delete (should have clicked keep files damn!) by mistake when detaching. Unfortunately I didn't have backup for it. All too late. What I have tried Tried to undelete (use testdisk and photorec) the vdi files but it takes too long and recovered heaps of .vdi files that I didn't want (huge, filled the disk, damn!). I finally gave up. Fortunately most of data is on separate ext4 partition and btrfs volumes. Out of curiosity, I still tried to mount the logical volumes and see if it is possible to at least recover the /var and /etc I tried to use system rescue cd to boot and activate the volume groups, I got: Couldn't find device with uuid xxxx. Refusing activation of the partial LV root. Use --partial to override. 1 logical volume(s) in volume group "ubuntu" now active. I was able to mount home LV but not root LV. I am wondering if it is possible to access the root LV any more. Under the bonnet, data (on LV root - /) was striped to more.vdi (PV), I know it's almost impossible to to recover. But I am still curious about how system administrator/DevOps guys deal with this sort of situation;-) Thanks in advance.

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• Document-oriented vs Column-oriented database fit

  - by user1007922

  I have a data-intensive application that desperately needs a database make-over. The general data model: There are records with RIDs, grouped together by group IDs (GID). The records have arbitrary data fields, (maybe 5-15) with a few of them mandatory and the rest optional, and thus sparse. The general use model: There are LOTS and LOTS of Writes. Millions to Billions of records are stored. Very often, they are associated with new GIDs, but sometimes, they are associated with existing GIDs. There aren't as many reads, but when they happen, they need to be pretty fast or at least constant speed regardless of the database size. And when the reads happen, it will need to retrieve all the records/RIDs with a certain GID. I don't have a need to search by the record field values. Primarily, I will need to query by the GID and maybe RID. What database implementation should I use? I did some initial research between document-oriented and column-oriented databases and it seems the document-oriented ones are a good fit, model-wise. I could store all the records together under the same document key using the GID. But I don't really have any use for their ability to search the document contents itself. I like the simplicity and scalability of column-oriented databases like Cassandra, but how should I model my data in this paradigm for optimal performance? Should my key be the GID and should I create a column for each record/RID? (there maybe thousands or hundreds of thousands of records in a group/GID). Or should my key be the RID and ensure each row has a column for the GID value? What results in faster writes and reads under this model?

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• How to read Scala code with lots of implicits?

  - by Petr Pudlák

  Consider the following code fragment (adapted from http://stackoverflow.com/a/12265946/1333025): // Using scalaz 6 import scalaz._, Scalaz._ object Example extends App { case class Container(i: Int) def compute(s: String): State[Container, Int] = state { case Container(i) => (Container(i + 1), s.toInt + i) } val d = List("1", "2", "3") type ContainerState[X] = State[Container, X] println( d.traverse[ContainerState, Int](compute) ! Container(0) ) } I understand what it does on high level. But I wanted to trace what exactly happens during the call to d.traverse at the end. Clearly, List doesn't have traverse, so it must be implicitly converted to another type that does. Even though I spent a considerable amount of time trying to find out, I wasn't very successful. First I found that there is a method in scalaz.Traversable traverse[F[_], A, B] (f: (A) => F[B], t: T[A])(implicit arg0: Applicative[F]): F[T[B]] but clearly this is not it (although it's most likely that "my" traverse is implemented using this one). After a lot of searching, I grepped scalaz source codes and I found scalaz.MA's method traverse[F[_], B] (f: (A) => F[B])(implicit a: Applicative[F], t: Traverse[M]): F[M[B]] which seems to be very close. Still I'm missing to what List is converted in my example and if it uses MA.traverse or something else. The question is: What procedure should I follow to find out what exactly is called at d.traverse? Having even such a simple code that is so hard analyze seems to me like a big problem. Am I missing something very simple? How should I proceed when I want to understand such code that uses a lot of imported implicits? Is there some way to ask the compiler what implicits it used? Or is there something like Hoogle for Scala so that I can search for a method just by its name?

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• New Regular Expression Features in Java 8

  - by Jan Goyvaerts

  Java 8 brings a few changes to Java’s regular expression syntax to make it more consistent with Perl 5.14 and later in matching horizontal and vertical whitespace. \h is a new feature. It is a shorthand character class that matches any horizontal whitespace character as defined in the Unicode standard. In Java 4 to 7 \v is a character escape that matches only the vertical tab character. In Java 8 \v is a shorthand character class that matches any vertical whitespace, including the vertical tab. When upgrading to Java 8, make sure that any regexes that use \v still do what you want. Use \x0B or \cK to match just the vertical tab in any version of Java. \R is also a new feature. It matches any line break as defined by the Unicode standard. Windows-style CRLF pairs are always matched as a whole. So \R matches \r\n while \R\R fails to match \r\n. \R is equivalent to (?\r\n|[\n\cK\f\r\u0085\u2028\u2029]) with an atomic group that prevents it from matching only the CR in a CRLF pair. Oracle’s documentation for the Pattern class omits the atomic group when explaining \R, which is incorrect. You cannot use \R inside a character class. RegexBuddy and RegexMagic have been updated to support Java 8. Java 4, 5, 6, and 7 are still supported. When you upgrade to Java 8 you can compare or convert your regular expressions between Java 8 and the Java version you were using previously.

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