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• Apache's htcacheclean doesn't scale: How to tame a huge Apache disk_cache?

  - by flight

  We have an Apache setup with a huge disk_cache (500.000 entries, 50 GB disk space used). The cache grows by 16 GB every day. My problem is that the cache seems to be growing nearly as fast as it's possible to remove files and directories from the cache filesystem! The cache partition is an ext3 filesystem (100GB, "-t news") on an iSCSI storage. The Apache server (which acts as a caching proxy) is a VM. The disk_cache is configured with CacheDirLevels=2 and CacheDirLength=1, and includes variants. A typical file path is "/htcache/B/x/i_iGfmmHhxJRheg8NHcQ.header.vary/A/W/oGX3MAV3q0bWl30YmA_A.header". When I try to call htcacheclean to tame the cache (non-daemon mode, "htcacheclean-t -p/htcache -l15G"), IOwait is going through the roof for several hours. Without any visible action. Only after hours, htcacheclean starts to delete files from the cache partition, which takes a couple more hours. (A similar problem was brought up in the Apache mailing list in 2009, without a solution: http://www.mail-archive.com/[email protected]/msg42683.html) The high IOwait leads to problems with the stability of the web server (the bridge to the Tomcat backend server sometimes stalls). I came up with my own prune script, which removes files and directories from random subdirectories of the cache. Only to find that the deletion rate of the script is just slightly higher than the cache growth rate. The script takes ~10 seconds to read the a subdirectory (e.g. /htcache/B/x) and frees some 5 MB of disk space. In this 10 seconds, the cache has grown by another 2 MB. As with htcacheclean, IOwait goes up to 25% when running the prune script continuously. Any idea? Is this a problem specific to the (rather slow) iSCSI storage? Should I choose a different file system for a huge disk_cache? ext2? ext4? Are there any kernel parameter optimizations for this kind of scenario? (I already tried the deadline scheduler and a smaller read_ahead_kb, without effect).

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• Google Rules for Retail

  - by David Dorf

  In the book What Would Google Do?, Jeff Jarvis outlines ten "Google Rules" that define how Google acts.  These rules help define how Web 2.0 businesses operate today and into the future.  While there's a chapter in the book on applying these rules to the retail industry, it wasn't very in-depth.  So I've decided to more directly apply the rules to retail, along with some notable examples of success.  The table below shows Jeff's Google Rule, some Industry Examples, and New Retailer Rules that I created. 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-top:0in; mso-para-margin-right:0in; mso-para-margin-bottom:10.0pt; mso-para-margin-left:0in; line-height:115%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin;} table.MsoTableGrid {mso-style-name:"Table Grid"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-priority:59; mso-style-unhide:no; border:solid black 1.0pt; mso-border-themecolor:text1; mso-border-alt:solid black .5pt; mso-border-themecolor:text1; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-border-insideh:.5pt solid black; mso-border-insideh-themecolor:text1; mso-border-insidev:.5pt solid black; mso-border-insidev-themecolor:text1; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin;} Google Rule Industry Examples New Retailer Rule New Relationship Your worst customer is your friend; you best customer is your partner Newegg.com lets manufacturers respond to customer comments that are critical of the product, and their EggXpert site lets customers help other customers. Listen to what your customers are saying about you.  Convert the critics to fans and the fans to influencers. New Architecture Join a network; be a platform Tesco and BestBuy released APIs for their product catalogs so third-parties could create new applications. Become a destination for information. New Publicness Life is public, so is business Zappos and WholeFoods founders are prolific tweeters/bloggers, sharing their opinions and connecting to customers.  It's not always pretty, but it's genuine. Be transparent.  Share both your successes and failures with your customers. New Society Elegant organization Wet Seal helps their customers assemble outfits and show them off to each other.  Barnes & Noble has a community site that includes a bookclub. Communities of your customers already exist, so help them organize better. New Economy Mass market is dead; long live the mass of niches lululemon found a niche for yoga inspired athletic wear.  Threadless uses crowd-sourcing to design short-runs of T-shirts. Serve small markets with niche products. New Business Reality Decide what business you're in When Lowes realized catering to women brought the men along, their sales increased. Customers want experiences to go with the products they buy. New Attitude Trust the people and listen In 2008 Starbucks launched MyStartbucksIdea to solicit ideas from their customers. Use social networks as additional data points for making better merchandising decisions. New Ethic Be honest and transparent; don't be evil Target is giving away reusable shopping bags for Earth Day.  Kohl's has outfitted 67 stores with solar arrays. Being green earns customers' respect and lowers costs too. New Speed Life is live H&M and Zara keep up with fashion trends. Be prepared to pounce on you customers' fickle interests. New Imperatives Encourage, enable and protect innovation 1-800-Flowers was the first do sales in Facebook and an early adopter of mobile commerce.  The Sears Personal Shopper mobile app finds products based on a photo. Give your staff permission to fail so innovation won't be stifled. Jeff will be a keynote speaker at Crosstalk, our upcoming annual user conference, so I'm looking forward to hearing more of his perspective on retail and the new economy.

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• JMS Step 1 - How to Create a Simple JMS Queue in Weblogic Server 11g

  - by John-Brown.Evans

  JMS Step 1 - How to Create a Simple JMS Queue in Weblogic Server 11g ol{margin:0;padding:0} .c5{vertical-align:top;width:156pt;border-style:solid;border-color:#000000;border-width:1pt;padding:0pt 2pt 0pt 2pt} .c7{list-style-type:disc;margin:0;padding:0} .c4{background-color:#ffffff} .c14{color:#1155cc;text-decoration:underline} .c6{height:11pt;text-align:center} .c13{color:inherit;text-decoration:inherit} .c3{padding-left:0pt;margin-left:36pt} .c0{border-collapse:collapse} .c12{text-align:center} .c1{direction:ltr} .c8{background-color:#f3f3f3} .c2{line-height:1.0} .c11{font-style:italic} .c10{height:11pt} .c9{font-weight:bold} .title{padding-top:24pt;line-height:1.15;text-align:left;color:#000000;font-size:36pt;font-family:"Arial";font-weight:bold;padding-bottom:6pt}.subtitle{padding-top:18pt;line-height:1.15;text-align:left;color:#666666;font-style:italic;font-size:24pt;font-family:"Georgia";padding-bottom:4pt} li{color:#000000;font-size:10pt;font-family:"Arial"} p{color:#000000;font-size:10pt;margin:0;font-family:"Arial"} h1{padding-top:0pt;line-height:1.15;text-align:left;color:#666;font-size:18pt;font-family:"Arial";font-weight:normal;padding-bottom:0pt} h2{padding-top:0pt;line-height:1.15;text-align:left;color:#666;font-size:14pt;font-family:"Arial";font-weight:normal;padding-bottom:0pt} h3{padding-top:0pt;line-height:1.15;text-align:left;color:#666;font-size:12pt;font-family:"Arial";font-weight:normal;padding-bottom:0pt} h4{padding-top:0pt;line-height:1.15;text-align:left;color:#666;font-style:italic;font-size:11pt;font-family:"Arial";padding-bottom:0pt} h5{padding-top:0pt;line-height:1.15;text-align:left;color:#666;font-size:10pt;font-family:"Arial";font-weight:normal;padding-bottom:0pt} h6{padding-top:0pt;line-height:1.15;text-align:left;color:#666;font-style:italic;font-size:10pt;font-family:"Arial";padding-bottom:0pt} This example shows the steps to create a simple JMS queue in WebLogic Server 11g for testing purposes. For example, to use with the two sample programs QueueSend.java and QueueReceive.java which will be shown in later examples. Additional, detailed information on JMS can be found in the following Oracle documentation: Oracle® Fusion Middleware Configuring and Managing JMS for Oracle WebLogic Server 11g Release 1 (10.3.6) Part Number E13738-06 http://docs.oracle.com/cd/E23943_01/web.1111/e13738/toc.htm 1. Introduction and Definitions A JMS queue in Weblogic Server is associated with a number of additional resources: JMS Server A JMS server acts as a management container for resources within JMS modules. Some of its responsibilities include the maintenance of persistence and state of messages and subscribers. A JMS server is required in order to create a JMS module. JMS Module A JMS module is a definition which contains JMS resources such as queues and topics. A JMS module is required in order to create a JMS queue. Subdeployment JMS modules are targeted to one or more WLS instances or a cluster. Resources within a JMS module, such as queues and topics are also targeted to a JMS server or WLS server instances. A subdeployment is a grouping of targets. It is also known as advanced targeting. Connection Factory A connection factory is a resource that enables JMS clients to create connections to JMS destinations. JMS Queue A JMS queue (as opposed to a JMS topic) is a point-to-point destination type. A message is written to a specific queue or received from a specific queue. The objects used in this example are: Object Name Type JNDI Name TestJMSServer JMS Server TestJMSModule JMS Module TestSubDeployment Subdeployment TestConnectionFactory Connection Factory jms/TestConnectionFactory TestJMSQueue JMS Queue jms/TestJMSQueue 2. Configuration Steps The following steps are done in the WebLogic Server Console, beginning with the left-hand navigation menu. 2.1 Create a JMS Server Services > Messaging > JMS Servers Select New Name: TestJMSServer Persistent Store: (none) Target: soa_server1  (or choose an available server) Finish The JMS server should now be visible in the list with Health OK. 2.2 Create a JMS Module Services > Messaging > JMS Modules Select New Name: TestJMSModule Leave the other options empty Targets: soa_server1  (or choose the same one as the JMS server)Press Next Leave “Would you like to add resources to this JMS system module” unchecked and  press Finish . 2.3 Create a SubDeployment A subdeployment is not necessary for the JMS queue to work, but it allows you to easily target subcomponents of the JMS module to a single target or group of targets. We will use the subdeployment in this example to target the following connection factory and JMS queue to the JMS server we created earlier. Services > Messaging > JMS Modules Select TestJMSModule Select the Subdeployments  tab and New Subdeployment Name: TestSubdeployment Press Next Here you can select the target(s) for the subdeployment. You can choose either Servers (i.e. WebLogic managed servers, such as the soa_server1) or JMS Servers such as the JMS Server created earlier. As the purpose of our subdeployment in this example is to target a specific JMS server, we will choose the JMS Server option. Select the TestJMSServer created earlier Press Finish 2.4  Create a Connection Factory Services > Messaging > JMS Modules Select TestJMSModule  and press New Select Connection Factory  and Next Name: TestConnectionFactory JNDI Name: jms/TestConnectionFactory Leave the other values at default On the Targets page, select the Advanced Targeting  button and select TestSubdeployment Press Finish The connection factory should be listed on the following page with TestSubdeployment and TestJMSServer as the target. 2.5 Create a JMS Queue Services > Messaging > JMS Modules Select TestJMSModule  and press New Select Queue and Next Name: TestJMSQueueJNDI Name: jms/TestJMSQueueTemplate: NonePress Next Subdeployments: TestSubdeployment Finish The TestJMSQueue should be listed on the following page with TestSubdeployment and TestJMSServer. Confirm the resources for the TestJMSModule. Using the Domain Structure tree, navigate to soa_domain > Services > Messaging > JMS Modules then select TestJMSModule You should see the following resources The JMS queue is now complete and can be accessed using the JNDI names jms/TestConnectionFactory andjms/TestJMSQueue. In the following blog post in this series, I will show you how to write a message to this queue, using the WebLogic sample Java program QueueSend.java.

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• Computer Networks UNISA - Chap 12 &ndash; Networking Security

  - by MarkPearl

  After reading this section you should be able to Identify security risks in LANs and WANs and design security policies that minimize risks Explain how physical security contributes to network security Discuss hardware and design based security techniques Understand methods of encryption such as SSL and IPSec, that can secure data in storage and in transit Describe how popular authentication protocols such as RADIUS< TACACS,Kerberos, PAP, CHAP, and MS-CHAP function Use network operating system techniques to provide basic security Understand wireless security protocols such as WEP, WPA and 802.11i Security Audits Before spending time and money on network security, examine your networks security risks – rate and prioritize risks. Different organizations have different levels of network security requirements. Security Risks Not all security breaches result from a manipulation of network technology – there are human factors that can play a role as well. The following categories are areas of considerations… Risks associated with People Risks associated with Transmission and Hardware Risks associated with Protocols and Software Risks associated with Internet Access An effective security policy A security policy identifies your security goals, risks, levels of authority, designated security coordinator and team members, responsibilities for each team member, and responsibilities for each employee. In addition it specifies how to address security breaches. It should not state exactly which hardware, software, architecture, or protocols will be used to ensure security, nor how hardware or software will be installed and configured. A security policy must address an organizations specific risks. to understand your risks, you should conduct a security audit that identifies vulnerabilities and rates both the severity of each threat and its likelihood of occurring. Security Policy Content Security policy content should… Policies for each category of security Explain to users what they can and cannot do and how these measures protect the networks security Should define what confidential means to the organization Response Policy A security policy should provide for a planned response in the event of a security breach. The response policy should identify the members of a response team, all of whom should clearly understand the the security policy, risks, and measures in place. Some of the roles concerned could include… Dispatcher – the person on call who first notices the breach Manager – the person who coordinates the resources necessary to solve the problem Technical Support Specialist – the person who focuses on solving the problem Public relations specialist – the person who acts as the official spokesperson for the organization Physical Security An important element in network security is restricting physical access to its components. There are various techniques for this including locking doors, security people at access points etc. You should identify the following… Which rooms contain critical systems or data and must be secured Through what means might intruders gain access to these rooms How and to what extent are authorized personnel granted access to these rooms Are authentication methods such as ID cards easy to forge etc. Security in Network Design The optimal way to prevent external security breaches from affecting you LAN is not to connect your LAN to the outside world at all. The next best protection is to restrict access at every point where your LAN connects to the rest of the world. Router Access List – can be used to filter or decline access to a portion of a network for certain devices. Intrusion Detection and Prevention While denying someone access to a section of the network is good, it is better to be able to detect when an attempt has been made and notify security personnel. This can be done using IDS (intrusion detection system) software. One drawback of IDS software is it can detect false positives – i.e. an authorized person who has forgotten his password attempts to logon. Firewalls A firewall is a specialized device, or a computer installed with specialized software, that selectively filters or blocks traffic between networks. A firewall typically involves a combination of hardware and software and may reside between two interconnected private networks. The simplest form of a firewall is a packet filtering firewall, which is a router that examines the header of every packet of data it receives to determine whether that type of packet is authorized to continue to its destination or not. Firewalls can block traffic in and out of a LAN. NOS (Network Operating System) Security Regardless of the operating system, generally every network administrator can implement basic security by restricting what users are authorized to do on a network. Some of the restrictions include things related to Logons – place, time of day, total time logged in, etc Passwords – length, characters used, etc Encryption Encryption is the use of an algorithm to scramble data into a format that can be read only by reversing the algorithm. The purpose of encryption is to keep information private. Many forms of encryption exist and new ways of cracking encryption are continually being invented. The following are some categories of encryption… Key Encryption PGP (Pretty Good Privacy) SSL (Secure Sockets Layer) SSH (Secure Shell) SCP (Secure CoPy) SFTP (Secure File Transfer Protocol) IPSec (Internet Protocol Security) For a detailed explanation on each section refer to pages 596 to 604 of textbook Authentication Protocols Authentication protocols are the rules that computers follow to accomplish authentication. Several types exist and the following are some of the common authentication protocols… RADIUS and TACACS PAP (Password Authentication Protocol) CHAP and MS-CHAP EAP (Extensible Authentication Protocol) 802.1x (EAPoL) Kerberos Wireless Network Security Wireless transmissions are particularly susceptible to eavesdropping. The following are two wireless network security protocols WEP WPA

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• Information Indepth Newsletter - Linux Edition

  - by Paulo Folgado

  INFORMATION INDEPTH NEWSLETTERLinux Edition February 2011 Stay Connected:  NEWS Now Available: Oracle Linux 6 Get the latest release of Oracle Linux 6, which includes Unbreakable Enterprise Kernel.Download Oracle Linux 6 Read More Customers Succeed by Using Oracle Exadata with Oracle Linux Watch IT executives from Bank of America, Linkshare, and Johns Hopkins as they talk about the business challenges they faced and why they chose to use Oracle Linux along with Oracle Exadata as the solution. Watch Now Video Interview: Oracle Senior Vice President Wim Coekaerts Watch Wim Coekaerts, senior vice president, Linux and Virtualization Engineering, as he talks about use cases for Oracle VM Templates as well as the Unbreakable Enterprise Kernel for Linux.Watch Now Hot Off the Press: Migrate Your IBM AIX Environment to Oracle Linux This new white paper provides recommendations for planning and implementing the migration of applications from an IBM Power System running AIX to Oracle's Sun Fire X4800 Server with Intel Xeon 7560 Processor running Oracle Linux 5.5.Read More  Back to Top BLOGOSPHERE Just Launched: The Oracle Linux Blog Follow our new Oracle Linux blog  to hear the latest updates, product news, upcoming events, and all the latest happenings, directly from the Linux team at Oracle. Back to Top TECH DIVE NEW: Linux/Oracle Solaris CommandComparo Site from Oracle Technology NetworkThis site gives equivalent command syntax in Oracle Solaris 10 and Oracle Enterprise Linux 5 for common administrative tasks--focusing particularly on tasks that have tricky syntax or that you frequently need to double check. It acts as a quick reference for administrators who operate in these two OS environments. Free Download: Oracle Linux Release 5.6Did you know that by using Oracle Linux 5.5 or 5.6 along with the Unbreakable Enterprise Kernel, you can get all the benefits of Linux mainline kernel 2.6.32 and more, right now, without the need to reinstall or migrate to a new operating system such as RHEL6?Read Release NotesDownload Oracle Linux 5.6 LSB 4.0 Certification Completed for Oracle Linux 5.5Oracle Linux 5.5 with Unbreakable Enterprise Kernel successfully completed the LSB 4.0 certification.  Back to Top WEBCASTS Boost Your Linux Performance with Oracle's Enhancements in Infiniband and RDSRegister to hear Director of Kernel Engineering Chris Mason cover scalability and performance improvements in Linux environment. Get the Facts Oracle's Unbreakable Enterprise KernelSVP Wim Coekaerts and Senior Director Monica Kumar cover the facts about and benefits of using Unbreakable Enterprise Kernel.  View Other Webcasts on Demand   Back to Top EVENTS Collaborate 2011April 10-14 Orlando, Florida Cloud Summit Events, WorldwideVarious dates (check the city for date/time of event) Datacenter Efficiency Events WorldwideThese events include Linux and Oracle VM sessions.Various dates (check the city for date/time of event) Virtualization Events in North America Find an Oracle Event  Back to Top EDUCATION Get Oracle Linux Certified from Oracle University Oracle University offers courses in both Oracle Linux and the administration of Oracle Database on Linux.  Back to Top CUSTOMER SPOTLIGHT Pella Corporation Improves IT Performance and Efficiency with Oracle Linux and Oracle VM To improve IT performance and efficiency and lower operational costs, Pella Corporation, has standardized on Oracle VM and Oracle Linux. Read More Disney Store Deploys POS in 330 Stores and 7 Countries on Oracle Linux Disney Store is running 1,500 registers worldwide on a broad Oracle technology software stack including Oracle Database 11g, Oracle Fusion Middleware, and Oracle Linux. Read More Back to Top PARTNER SPOTLIGHT Emulex and Oracle Announce Data Integrity Features The Unbreakable Enterprise Kernel provides data integrity checking between Oracle Database applications and Emulex 8Gb/s LightPulse Fibre Channel Host Bus Adapters. Read More Dell Inc. Dell Inc. tested and validated configurations support Oracle Linux. Back to Top STAY IN TOUCH Follow @ORCL_Linux on Twitter for the latest penguin tweets Bookmark Oracle.com/Linux Read the Oracle Linux blog Back to Top  Oracle Information InDepth newsletters bring targeted news, articles, customer stories, and special offers to business people who want to find out how to streamline enterprise information management, measure results, improve business processes, and communicate a single truth to their constituents. Please send questions or comments to [email protected]. For answers to questions about subscribing, unsubscribing, and managing your Oracle e-mail communications preferences, please see the Oracle E-Mail Communications page. Copyright © 2011, Oracle Corporation and/or its affiliates. All rights reserved. Oracle is a registered trademark of Oracle Corporation and/or its affiliates. Other names may be trademarks of their respective owners. This document is provided for information purposes only, and the contents hereof are subject to change without notice. This document is not warranted to be error-free, nor is it subject to any other warranties or conditions, whether expressed orally or implied in law, including implied warranties and conditions of merchantability or fitness for a particular purpose. We specifically disclaim any liability with respect to this document, and no contractual obligations are formed either directly or indirectly by this document. This document may not be reproduced or transmitted in any form or by any means, electronic or mechanical, for any purpose, without our prior written permission. 

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• Windows Azure Use Case: Hybrid Applications

  - by BuckWoody

  This is one in a series of posts on when and where to use a distributed architecture design in your organization's computing needs. You can find the main post here: http://blogs.msdn.com/b/buckwoody/archive/2011/01/18/windows-azure-and-sql-azure-use-cases.aspx  Description: Organizations see the need for computing infrastructures that they can “rent” or pay for only when they need them. They also understand the benefits of distributed computing, but do not want to create this infrastructure themselves. However, they may have considerations that prevent them from moving all of their current IT investment to a distributed environment: Private data (do not want to send or store sensitive data off-site) High dollar investment in current infrastructure Applications currently running well, but may need additional periodic capacity Current applications not designed in a stateless fashion In these situations, a “hybrid” approach works best. In fact, with Windows Azure, a hybrid approach is an optimal way to implement distributed computing even when the stipulations above do not apply. Keeping a majority of the computing function in an organization local while exploring and expanding that footprint into Windows and SQL Azure is a good migration or expansion strategy. A “hybrid” architecture merely means that part of a computing cycle is shared between two architectures. For instance, some level of computing might be done in a Windows Azure web-based application, while the data is stored locally at the organization. Implementation: There are multiple methods for implementing a hybrid architecture, in a spectrum from very little interaction from the local infrastructure to Windows or SQL Azure. The patterns fall into two broad schemas, and even these can be mixed. 1. Client-Centric Hybrid Patterns In this pattern, programs are coded such that the client system sends queries or compute requests to multiple systems. The “client” in this case might be a web-based codeset actually stored on another system (which acts as a client, the user’s device serving as the presentation layer) or a compiled program. In either case, the code on the client requestor carries the burden of defining the layout of the requests. While this pattern is often the easiest to code, it’s the most brittle. Any change in the architecture must be reflected on each client, but this can be mitigated by using a centralized system as the client such as in the web scenario. 2. System-Centric Hybrid Patterns Another approach is to create a distributed architecture by turning on-site systems into “services” that can be called from Windows Azure using the service Bus or the Access Control Services (ACS) capabilities. Code calls from a series of in-process client application. In this pattern you move the “client” interface into the server application logic. If you do not wish to change the application itself, you can “layer” the results of the code return using a product (such as Microsoft BizTalk) that exposes a Web Services Definition Language (WSDL) endpoint to Windows Azure using the Application Fabric. In effect, this is similar to creating a Service Oriented Architecture (SOA) environment, and has the advantage of de-coupling your computing architecture. If each system offers a “service” of the results of some software processing, the operating system or platform becomes immaterial, assuming it adheres to a service contract. There are important considerations when you federate a system, whether to Windows or SQL Azure or any other distributed architecture. While these considerations are consistent with coding any application for distributed computing, they are especially important for a hybrid application. Connection resiliency - Applications on-premise normally have low-latency and good connection properties, something you’re not always guaranteed in a distributed and hybrid application. Whether a centralized client or a distributed one, the code should be able to handle extended retry logic. Authorization and Access - In a single authorization environment like a Active Directory domain, security is handled at a user-password level. In a distributed computing environment, you have more options. You can mitigate this with  using The Windows Azure Application Fabric feature of ACS to make the Azure application aware of the App Fabric as an ADFS provider. However, a claims-based authentication structure is often a superior choice.  Consistency and Concurrency - When you have a Relational Database Management System (RDBMS), Consistency and Concurrency are part of the design. In a Service Architecture, you need to plan for sequential message handling and lifecycle. Resources: How to Build a Hybrid On-Premise/In Cloud Application: http://blogs.msdn.com/b/ignitionshowcase/archive/2010/11/09/how-to-build-a-hybrid-on-premise-in-cloud-application.aspx  General Architecture guidance: http://blogs.msdn.com/b/buckwoody/archive/2010/12/21/windows-azure-learning-plan-architecture.aspx   

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• Replication Services in a BI environment

  - by jorg

  In this blog post I will explain the principles of SQL Server Replication Services without too much detail and I will take a look on the BI capabilities that Replication Services could offer in my opinion. SQL Server Replication Services provides tools to copy and distribute database objects from one database system to another and maintain consistency afterwards. These tools basically copy or synchronize data with little or no transformations, they do not offer capabilities to transform data or apply business rules, like ETL tools do. The only “transformations” Replication Services offers is to filter records or columns out of your data set. You can achieve this by selecting the desired columns of a table and/or by using WHERE statements like this: SELECT <published_columns> FROM [Table] WHERE [DateTime] >= getdate() - 60 There are three types of replication: Transactional Replication This type replicates data on a transactional level. The Log Reader Agent reads directly on the transaction log of the source database (Publisher) and clones the transactions to the Distribution Database (Distributor), this database acts as a queue for the destination database (Subscriber). Next, the Distribution Agent moves the cloned transactions that are stored in the Distribution Database to the Subscriber. The Distribution Agent can either run at scheduled intervals or continuously which offers near real-time replication of data! So for example when a user executes an UPDATE statement on one or multiple records in the publisher database, this transaction (not the data itself) is copied to the distribution database and is then also executed on the subscriber. When the Distribution Agent is set to run continuously this process runs all the time and transactions on the publisher are replicated in small batches (near real-time), when it runs on scheduled intervals it executes larger batches of transactions, but the idea is the same. Snapshot Replication This type of replication makes an initial copy of database objects that need to be replicated, this includes the schemas and the data itself. All types of replication must start with a snapshot of the database objects from the Publisher to initialize the Subscriber. Transactional replication need an initial snapshot of the replicated publisher tables/objects to run its cloned transactions on and maintain consistency. The Snapshot Agent copies the schemas of the tables that will be replicated to files that will be stored in the Snapshot Folder which is a normal folder on the file system. When all the schemas are ready, the data itself will be copied from the Publisher to the snapshot folder. The snapshot is generated as a set of bulk copy program (BCP) files. Next, the Distribution Agent moves the snapshot to the Subscriber, if necessary it applies schema changes first and copies the data itself afterwards. The application of schema changes to the Subscriber is a nice feature, when you change the schema of the Publisher with, for example, an ALTER TABLE statement, that change is propagated by default to the Subscriber(s). Merge Replication Merge replication is typically used in server-to-client environments, for example when subscribers need to receive data, make changes offline, and later synchronize changes with the Publisher and other Subscribers, like with mobile devices that need to synchronize one in a while. Because I don’t really see BI capabilities here, I will not explain this type of replication any further. Replication Services in a BI environment Transactional Replication can be very useful in BI environments. In my opinion you never want to see users to run custom (SSRS) reports or PowerPivot solutions directly on your production database, it can slow down the system and can cause deadlocks in the database which can cause errors. Transactional Replication can offer a read-only, near real-time database for reporting purposes with minimal overhead on the source system. Snapshot Replication can also be useful in BI environments, if you don’t need a near real-time copy of the database, you can choose to use this form of replication. Next to an alternative for Transactional Replication it can be used to stage data so it can be transformed and moved into the data warehousing environment afterwards. In many solutions I have seen developers create multiple SSIS packages that simply copies data from one or more source systems to a staging database that figures as source for the ETL process. The creation of these packages takes a lot of (boring) time, while Replication Services can do the same in minutes. It is possible to filter out columns and/or records and it can even apply schema changes automatically so I think it offers enough features here. I don’t know how the performance will be and if it really works as good for this purpose as I expect, but I want to try this out soon!

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• SQL SERVER – Auditing and Profiling Database Made Easy with SQL Audit and Comply

  - by Pinal Dave

  Do you like auditing your database, or can you think of about a million other things you’d rather do?  Unfortunately, auditing is incredibly important.  As with tax audits, it is important to audit databases to ensure they are following all the rules, but they are also important for troubleshooting and security. There are several ways to audit SQL Server.  There is manual auditing, which is going through your database “by hand,” and obviously takes a long time and is quite inefficient.  SQL Server also provides programs to help you audit your systems.  Different administrators will have different opinions about best practices and which tools to use, and each one will be perfected for certain systems and certain users. Today, though, I would like to talk about Apex SQL Audit.  It is an auditing tool that acts like “track changes” in a word processing document.  It will log what has changed on the database, who made the changes, and what effects these changes have had (i.e. what objects were affected down the line).  All this information is logged, and can be easily viewed or printed for easy access. One of the best features of Apex is that it is so customizable (and easy to use!).  First, start Apex.  Then you can connect to the database you would like to monitor. Once you select your database, you can select which table you want to audit. You can customize right down to the field you’d like to audit, and then select which types of actions you’d like tracked – insert, delete, or update.  Repeat these steps for every database you want monitored. To create the logs, choose “Create triggers” in the menu.  The script written here will be what logs each insert, delete, and update function.  Press F5 to execute.  All this tracking information will be stored in AUDIT_LOG_DATA and AUDIT_LOG_TRANSACTIONS tables.  View these tables using ApexSQL Audit reports. These transaction logs can be extremely detailed – especially on very busy servers, where every move it traced.  Reading them can be overwhelming, to say the least.  Apex has tried to make things easier for the average DBA, though. You can read these tracking logs in Apex, and it will display data and objects that affect your server – even things that were happening on your server before you installed Apex! To read these logs, open Apex, and connect to that database you want to audit. Go to the Transaction Logs tab, and add the logs you want to read. To narrow down what results you want to see, you can use the Filter tab to choose time, operation type, name, users, and more. Click Open, and you can see the results in a grid (as shown below).  You can export these results to CSV, HTML, XML or SQL files and save on the hard disk. One of the advantages is that since there are no triggers here, there are no other processes that will affect SQL Server performance.  Using this method is also how to view history from your database that occurred before Apex was installed.  This type of tracking does require storage space for the data sources, as the database must be fully running, and the transaction logs must exist (things not stored in the transactions logs will not be recoverable). Apex can also replace SQL Server Profiler and SQL Server Traces – which are much more complex and error-prone – with its ApexSQL Comply.  It can do fault tolerant auditing, centralized reporting, and “who saw what” information in an easy-to-use interface.  The tracking settings can be altered by the user, or the default options will provide solutions to the most common auditing problems. To get started: open ApexSQL Comply, and selected Database Filter Settings to choose which database you’d like to audit.  You can select which tracking you’re like in Operation Types – DML, DDL, queries executed, execute statements, and more.  To get started, click Start Auditing. After this, every action will be stored in the central repository database (ApexSQLCrd).  You can view the audit and create a report (or view the standard default report) using a wizard. You can see how easy it is to use ApexSQL Comply.  You can easily set audits, including the type and time, and create customized reports.  Remote users can easily access the reports through the user interface (available online, as well), and security concerns are all taken care of by the program.  Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, SQL Utility, T SQL, Technology

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• Plan your SharePoint 2010 Content Type Hub carefully

  - by Wayne

  Currently setting up a new environment on SharePoint 2010 (which was made available for download yesterday if anyone missed that :-). One of the new features of SharePoint 2010 is to set up a Content Type Hub (which is a part of the Metadata Service Application), which is a hub for all Content Types that other Site Collections can subscribe to. That is you only need to manage your content types in one location. Setting up the Content Type Hub is not that difficult but you must make it very careful to avoid a lot of work and troubleshooting. Here is a short tutorial with a few tips and tricks to make it easy for you to get started. Determine location of Content Type Hub First of all you need to decide in which Site Collection to place your Content Type Hub; in the root site collection or a specific one. I think using a specific Site Collection that only acts as a Content Type Hub is the best way, there are no best practice as of now. So I create a new Site Collection, at for instance http://server/sites/CTH/. The top-level site of this site collection should be for instance a Team Site. You cannot use Blank Site by default, which would have been the best option IMHO, since that site does not have the Taxonomy feature stapled upon it (check the TaxonomyFeatureStapler feature for which site templates that can be used). Configure Managed Metadata Service Application Next you need to create your Managed Metadata Service Application or configure the existing one, Central Administration > Application Management > Manage Service Applications. Select the Managed Metadata service application and click Properties if you already have created it. In the bottom of the dialog window when you are creating the service application or when you are editing the properties is a section to fill in the Content Type Hub. In this text box fill in the URL of the Content Type Hub. It is essential that you have decided where your Content Type Hub will reside, since once this is set you cannot change it. The only way to change it is to rebuild the whole managed metadata service application! Also make sure that you enter the URL correctly. I did copy and paste the URL once and got the /default.aspx in the URL which funked the whole service up. Make sure that you only use the URL to the Site Collection of the hub. Now you have to set up so that other Site Collections can consume the content types from the hub. This is done by selecting the connection for the managed metadata service application and clicking properties. A new dialog window opens and there you need to click the Consumes content types from the Content Type Gallery at nnnn. Now you are free to syndicate your Content Types from the Hub. Publish Content Types To publish a Content Type from the hub you need to go to Site Settings > Content Types and select the content type that you would like to publish. Then select Manage publishing for this content type. This takes you to a page from where you can Publish, Unpublish or Republish the content type. Once the content type is published it can take up to an hour for the subscribing Site Collections to get it. This is controlled by the Content Type Subscriber job that is scheduled to run once an hour. To speed up your publishing just go to Central Administration > Monitoring > Review Job Definitions > Content Type Subscriber and click Run now and you content type is very soon available for use. Published Content Type status You can check the status of the content type publishing in your destination site collections by selecting Site Settings > Content Type Publishing. From here you can force a refresh of all subscribed content types, see which ones that are subscribed and finally check the publishing error log. This error log is very useful for detecting errors during the publishing. For instance if you use any features such as ratings, metadata, document ids in your content type hub and your destination site collection does not have those features available this will be reported here.

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• Demystified - BI in SharePoint 2010

  - by Sahil Malik

  Ad:: SharePoint 2007 Training in .NET 3.5 technologies (more information). Frequently, my clients ask me if there is a good guide on deciphering the seemingly daunting choice of products from Microsoft when it comes to business intelligence offerings in a SharePoint 2010 world. These are all described in detail in my book, but here is a one (well maybe two) page executive overview. Microsoft Excel: Yes, Microsoft Excel! Your favorite and most commonly used in the world database. No it isn’t a database in technical pure definitions, but this is the most commonly used ‘database’ in the world. You will find many business users craft up very compelling excel sheets with tonnes of logic inside them. Good for: Quick Ad-Hoc reports. Excel 64 bit allows the possibility of very large datasheets (Also see 32 bit vs 64 bit Office, and PowerPivot Add-In below). Audience: End business user can build such solutions. Related technologies: PowerPivot, Excel Services Microsoft Excel with PowerPivot Add-In: The powerpivot add-in is an extension to Excel that adds support for large-scale data. Think of this as Excel with the ability to deal with very large amounts of data. It has an in-memory data store as an option for Analysis services. Good for: Ad-hoc reporting and logic with very large amounts of data. Audience: End business user can build such solutions. Related technologies: Excel, and Excel Services Excel Services: Excel Services is a Microsoft SharePoint Server 2010 shared service that brings the power of Excel to SharePoint Server by providing server-side calculation and browser-based rendering of Excel workbooks. Thus, excel sheets can be created by end users, and published to SharePoint server – which are then rendered right through the browser in read-only or parameterized-read-only modes. They can also be accessed by other software via SOAP or REST based APIs. Good for: Sharing excel sheets with a larger number of people, while maintaining control/version control etc. Sharing logic embedded in excel sheets with other software across the organization via REST/SOAP interfaces Audience: End business users can build such solutions once your tech staff has setup excel services on a SharePoint server instance. Programmers can write software consuming functionality/complex formulae contained in your sheets. Related technologies: PerformancePoint Services, Excel, and PowerPivot. Visio Services: Visio Services is a shared service on the Microsoft SharePoint Server 2010 platform that allows users to share and view Visio diagrams that may or may not have data connected to them. Connected data can update these diagrams allowing a visual/graphical view into the data. The diagrams are viewable through the browser. They are rendered in silverlight, but will automatically down-convert to .png formats. Good for: Showing data as diagrams, live updating. Comes with a developer story. Audience: End business users can build such solutions once your tech staff has setup visio services on a SharePoint server instance. Developers can enhance the visualizations Related Technologies: Visio Services can be used to render workflow visualizations in SP2010 Reporting Services: SQL Server reporting services can integrate with SharePoint, allowing you to store reports and data sources in SharePoint document libraries, and render these reports and associated functionality such as subscriptions through a SharePoint site. In SharePoint 2010, you can also write reports against SharePoint lists (access services uses this technique). Good for: Showing complex reports running in a industry standard data store, such as SQL server. Audience: This is definitely developer land. Don’t expect end users to craft up reports, unless a report model has previously been published. Related Technologies: PerformancePoint Services PerformancePoint Services: PerformancePoint Services in SharePoint 2010 is now fully integrated with SharePoint, and comes with features that can either be used in the BI center site definition, or on their own as activated features in existing site collections. PerformancePoint services allows you to build reports and dashboards that target a variety of back-end datasources including: SQL Server reporting services, SQL Server analysis services, SharePoint lists, excel services, simple tables, etc. Using these you have the ability to create dashboards, scorecards/kpis, and simple reports. You can also create reports targeting hierarchical multidimensional data sources. The visual decomposition tree is a new report type that lets you quickly breakdown multi-dimensional data. Good for: Mostly everything :), except your wallet – it’s not free! But this is the most comprehensive offering. If you have SharePoint server, forget everything and go with performance point. Audience: Developers need to setup the back-end sources, manageability story. DBAs need to setup datawarehouses with cubes. Moderately sophisticated business users, or developers can craft up reports using dashboard designer which is a click-once App that deploys with PerformancePoint Related Technologies: Excel services, reporting services, etc.   Other relevant technologies to know about: Business Connectivity Services: Allows for consumption of external data in SharePoint as columns or external lists. This can be paired with one or more of the above BI offerings allowing insight into such data. Access Services: Allows the representation/publishing of an access database as a SharePoint 2010 site, leveraging many SharePoint features. Reporting services is used by Access services. Secure Store Service: The SP2010 Secure store service is a replacement for the SP2007 single sign on feature. This acts as a credential policeman providing credentials to various applications running with SharePoint. BCS, PerformancePoint Services, Excel Services, and many other apps use the SSS (Secure Store Service) for credential control. Comment on the article ....

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• Write your Tests in RSpec with IronRuby

  - by kazimanzurrashid

  [Note: This is not a continuation of my previous post, treat it as an experiment out in the wild. ] Lets consider the following class, a fictitious Fund Transfer Service: public class FundTransferService : IFundTransferService { private readonly ICurrencyConvertionService currencyConvertionService; public FundTransferService(ICurrencyConvertionService currencyConvertionService) { this.currencyConvertionService = currencyConvertionService; } public void Transfer(Account fromAccount, Account toAccount, decimal amount) { decimal convertionRate = currencyConvertionService.GetConvertionRate(fromAccount.Currency, toAccount.Currency); decimal convertedAmount = convertionRate * amount; fromAccount.Withdraw(amount); toAccount.Deposit(convertedAmount); } } public class Account { public Account(string currency, decimal balance) { Currency = currency; Balance = balance; } public string Currency { get; private set; } public decimal Balance { get; private set; } public void Deposit(decimal amount) { Balance += amount; } public void Withdraw(decimal amount) { Balance -= amount; } } We can write the spec with MSpec + Moq like the following: public class When_fund_is_transferred { const decimal ConvertionRate = 1.029m; const decimal TransferAmount = 10.0m; const decimal InitialBalance = 100.0m; static Account fromAccount; static Account toAccount; static FundTransferService fundTransferService; Establish context = () => { fromAccount = new Account("USD", InitialBalance); toAccount = new Account("CAD", InitialBalance); var currencyConvertionService = new Moq.Mock<ICurrencyConvertionService>(); currencyConvertionService.Setup(ccv => ccv.GetConvertionRate(Moq.It.IsAny<string>(), Moq.It.IsAny<string>())).Returns(ConvertionRate); fundTransferService = new FundTransferService(currencyConvertionService.Object); }; Because of = () => { fundTransferService.Transfer(fromAccount, toAccount, TransferAmount); }; It should_decrease_from_account_balance = () => { fromAccount.Balance.ShouldBeLessThan(InitialBalance); }; It should_increase_to_account_balance = () => { toAccount.Balance.ShouldBeGreaterThan(InitialBalance); }; } and if you run the spec it will give you a nice little output like the following: When fund is transferred » should decrease from account balance » should increase to account balance 2 passed, 0 failed, 0 skipped, took 1.14 seconds (MSpec). Now, lets see how we can write exact spec in RSpec. require File.dirname(__FILE__) + "/../FundTransfer/bin/Debug/FundTransfer" require "spec" require "caricature" describe "When fund is transferred" do Convertion_Rate = 1.029 Transfer_Amount = 10.0 Initial_Balance = 100.0 before(:all) do @from_account = FundTransfer::Account.new("USD", Initial_Balance) @to_account = FundTransfer::Account.new("CAD", Initial_Balance) currency_convertion_service = Caricature::Isolation.for(FundTransfer::ICurrencyConvertionService) currency_convertion_service.when_receiving(:get_convertion_rate).with(:any, :any).return(Convertion_Rate) fund_transfer_service = FundTransfer::FundTransferService.new(currency_convertion_service) fund_transfer_service.transfer(@from_account, @to_account, Transfer_Amount) end it "should decrease from account balance" do @from_account.balance.should be < Initial_Balance end it "should increase to account balance" do @to_account.balance.should be > Initial_Balance end end I think the above code is self explanatory, treat the require(line 1- 4) statements as the add reference of our visual studio projects, we are adding all the required libraries with this statement. Next, the describe which is a RSpec keyword. The before does exactly the same as NUnit's Setup or MsTest’s TestInitialize attribute, but in the above we are using before(:all) which acts as ClassInitialize of MsTest, that means it will be executed only once before all the test methods. In the before(:all) we are first instantiating the from and to accounts, it is same as creating with the full name (including namespace)  like fromAccount = new FundTransfer.Account(.., ..), next, we are creating a mock object of ICurrencyConvertionService, check that for creating the mock we are not using the Moq like the MSpec version. This is somewhat an interesting issue of IronRuby or maybe the DLR, it seems that it is not possible to use the lambda expression that most of the mocking tools uses in arrange phase in Iron Ruby, like: currencyConvertionService.Setup(ccv => ccv.GetConvertionRate(Moq.It.IsAny<string>(), Moq.It.IsAny<string>())).Returns(ConvertionRate); But the good news is, there is already an excellent mocking tool called Caricature written completely in IronRuby which we can use to mock the .NET classes. May be all the mocking tool providers should give some thought to add the support for the DLR, so that we can use the tool that we are already familiar with. I think the rest of the code is too simple, so I am skipping the explanation. Now, the last thing, how we are going to run it with RSpec, lets first install the required gems. Open you command prompt and type the following: igem sources -a http://gems.github.com This will add the GitHub as gem source. Next type: igem install uuidtools caricature rspec and at last we have to create a batch file so that we can execute it in the Notepad++, create a batch like in the IronRuby bin directory like my previous post and put the following in that batch file: @echo off cls call spec %1 --format specdoc pause Next, add a run menu and shortcut in the Notepad++ like my previous post. Now when we run it it will show the following output: When fund is transferred - should decrease from account balance - should increase to account balance Finished in 0.332042 seconds 2 examples, 0 failures Press any key to continue . . . You will complete code of this post in the bottom. That's it for today. Download: RSpecIntegration.zip

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• Real-world SignalR example, ditching ghetto long polling

  - by Jeff

  One of the highlights of BUILD last week was the announcement that SignalR, a framework for real-time client to server (or cloud, if you will) communication, would be a real supported thing now with the weight of Microsoft behind it. Love the open source flava! If you aren’t familiar with SignalR, watch this BUILD session with PM Damian Edwards and dev David Fowler. Go ahead, I’ll wait. You’ll be in a happy place within the first ten minutes. If you skip to the end, you’ll see that they plan to ship this as a real first version by the end of the year. Insert slow clap here. Writing a few lines of code to move around a box from one browser to the next is a way cool demo, but how about something real-world? When learning new things, I find it difficult to be abstract, and I like real stuff. So I thought about what was in my tool box and the decided to port my crappy long-polling “there are new posts” feature of POP Forums to use SignalR. A few versions back, I added a feature where a button would light up while you were pecking out a reply if someone else made a post in the interim. It kind of saves you from that awkward moment where someone else posts some snark before you. While I was proud of the feature, I hated the implementation. When you clicked the reply button, it started polling an MVC URL asking if the last post you had matched the last one the server, and it did it every second and a half until you either replied or the server told you there was a new post, at which point it would display that button. The code was not glam: // in the reply setup PopForums.replyInterval = setInterval("PopForums.pollForNewPosts(" + topicID + ")", 1500); // called from the reply setup and the handler that fetches more posts PopForums.pollForNewPosts = function (topicID) { $.ajax({ url: PopForums.areaPath + "/Forum/IsLastPostInTopic/" + topicID, type: "GET", dataType: "text", data: "lastPostID=" + PopForums.currentTopicState.lastVisiblePost, success: function (result) { var lastPostLoaded = result.toLowerCase() == "true"; if (lastPostLoaded) { $("#MorePostsBeforeReplyButton").css("visibility", "hidden"); } else { $("#MorePostsBeforeReplyButton").css("visibility", "visible"); clearInterval(PopForums.replyInterval); } }, error: function () { } }); }; What’s going on here is the creation of an interval timer to keep calling the server and bugging it about new posts, and setting the visibility of a button appropriately. It looks like this if you’re monitoring requests in FireBug: Gross. The SignalR approach was to call a message broker when a reply was made, and have that broker call back to the listening clients, via a SingalR hub, to let them know about the new post. It seemed weird at first, but the server-side hub’s only method is to add the caller to a group, so new post notifications only go to callers viewing the topic where a new post was made. Beyond that, it’s important to remember that the hub is also the means to calling methods at the client end. Starting at the server side, here’s the hub: using Microsoft.AspNet.SignalR.Hubs; namespace PopForums.Messaging { public class Topics : Hub { public void ListenTo(int topicID) { Groups.Add(Context.ConnectionId, topicID.ToString()); } } } Have I mentioned how awesomely not complicated this is? The hub acts as the channel between the server and the client, and you’ll see how JavaScript calls the above method in a moment. Next, the broker class and its associated interface: using Microsoft.AspNet.SignalR; using Topic = PopForums.Models.Topic; namespace PopForums.Messaging { public interface IBroker { void NotifyNewPosts(Topic topic, int lasPostID); } public class Broker : IBroker { public void NotifyNewPosts(Topic topic, int lasPostID) { var context = GlobalHost.ConnectionManager.GetHubContext<Topics>(); context.Clients.Group(topic.TopicID.ToString()).notifyNewPosts(lasPostID); } } } The NotifyNewPosts method uses the static GlobalHost.ConnectionManager.GetHubContext<Topics>() method to get a reference to the hub, and then makes a call to clients in the group matched by the topic ID. It’s calling the notifyNewPosts method on the client. The TopicService class, which handles the reply data from the MVC controller, has an instance of the broker new’d up by dependency injection, so it took literally one line of code in the reply action method to get things moving. _broker.NotifyNewPosts(topic, post.PostID); The JavaScript side of things wasn’t much harder. When you click the reply button (or quote button), the reply window opens up and fires up a connection to the hub: var hub = $.connection.topics; hub.client.notifyNewPosts = function (lastPostID) { PopForums.setReplyMorePosts(lastPostID); }; $.connection.hub.start().done(function () { hub.server.listenTo(topicID); }); The important part to look at here is the creation of the notifyNewPosts function. That’s the method that is called from the server in the Broker class above. Conversely, once the connection is done, the script calls the listenTo method on the server, letting it know that this particular connection is listening for new posts on this specific topic ID. This whole experiment enables a lot of ideas that would make the forum more Facebook-like, letting you know when stuff is going on around you.

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• IRM Item Codes &ndash; what are they for?

  - by martin.abrahams

  A number of colleagues have been asking about IRM item codes recently – what are they for, when are they useful, how can you control them to meet some customer requirements? This is quite a big topic, but this article provides a few answers. An item code is part of the metadata of every sealed document – unless you define a custom metadata model. The item code is defined when a file is sealed, and usually defaults to a timestamp/filename combination. This time/name combo tends to make item codes unique for each new document, but actually item codes are not necessarily unique, as will become clear shortly. In most scenarios, item codes are not relevant to the evaluation of a user’s rights - the context name is the critical piece of metadata, as a user typically has a role that grants access to an entire classification of information regardless of item code. This is key to the simplicity and manageability of the Oracle IRM solution. Item codes are occasionally exposed to users in the UI, but most users probably never notice and never care. Nevertheless, here is one example of where you can see an item code – when you hover the mouse pointer over a sealed file. As you see, the item code for this freshly created file combines a timestamp with the file name. But what are item codes for? The first benefit of item codes is that they enable you to manage exceptions to the policy defined for a context. Thus, I might have access to all oracle – internal files - except for 2011_03_11 13:33:29 Board Minutes.sdocx. This simple mechanism enables Oracle IRM to provide file-by-file control where appropriate, whilst offering the scalability and manageability of classification-based control for the majority of users and content. You really don’t want to be managing each file individually, but never say never. Item codes can also be used for the opposite effect – to include a file in a user’s rights when their role would ordinarily deny access. So, you can assign a role that allows access only to specified item codes. For example, my role might say that I have access to precisely one file – the one shown above. So how are item codes set? In the vast majority of scenarios, item codes are set automatically as part of the sealing process. The sealing API uses the timestamp and filename as shown, and the user need not even realise that this has happened. This automatically creates item codes that are for all practical purposes unique - and that are also intelligible to users who might want to refer to them when viewing or assigning rights in the management UI. It is also possible for suitably authorised users and applications to set the item code manually or programmatically if required. Setting the item code manually using the IRM Desktop The manual process is a simple extension of the sealing task. An authorised user can select the Advanced… sealing option, and will see a dialog that offers the option to specify the item code. To see this option, the user’s role needs the Set Item Code right – you don’t want most users to give any thought at all to item codes, so by default the option is hidden. Setting the item code programmatically A more common scenario is that an application controls the item code programmatically. For example, a document management system that seals documents as part of a workflow might set the item code to match the document’s unique identifier in its repository. This offers the option to tie IRM rights evaluation directly to the security model defined in the document management system. Again, the sealing application needs to be authorised to Set Item Code. The Payslip Scenario To give a concrete example of how item codes might be used in a real world scenario, consider a Human Resources workflow such as a payslips. The goal might be to allow the HR team to have access to all payslips, but each employee to have access only to their own payslips. To enable this, you might have an IRM classification called Payslips. The HR team have a role in the normal way that allows access to all payslips. However, each employee would have an Item Reader role that only allows them to access files that have a particular item code – and that item code might match the employee’s payroll number. So, employee number 123123123 would have access to items with that code. This shows why item codes are not necessarily unique – you can deliberately set the same code on many files for ease of administration. The employees might have the right to unseal or print their payslip, so the solution acts as a secure delivery mechanism that allows payslips to be distributed via corporate email without any fear that they might be accessed by IT administrators, or forwarded accidentally to anyone other than the intended recipient. All that remains is to ensure that as each user’s payslip is sealed, it is assigned the correct item code – something that is easily managed by a simple IRM sealing application. Each month, an employee’s payslip is sealed with the same item code, so you do not need to keep amending the list of items that the user has access to – they have access to all documents that carry their employee code.

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• ODI 12c - Aggregating Data

  - by David Allan

  This posting will look at the aggregation component that was introduced in ODI 12c. For many ETL tool users this shouldn't be a big surprise, its a little different than ODI 11g but for good reason. You can use this component for composing data with relational like operations such as sum, average and so forth. Also, Oracle SQL supports special functions called Analytic SQL functions, you can use a specially configured aggregation component or the expression component for these now in ODI 12c. In database systems an aggregate transformation is a transformation where the values of multiple rows are grouped together as input on certain criteria to form a single value of more significant meaning - that's exactly the purpose of the aggregate component. In the image below you can see the aggregate component in action within a mapping, for how this and a few other examples are built look at the ODI 12c Aggregation Viewlet here - the viewlet illustrates a simple aggregation being built and then some Oracle analytic SQL such as AVG(EMP.SAL) OVER (PARTITION BY EMP.DEPTNO) built using both the aggregate component and the expression component. In 11g you used to just write the aggregate expression directly on the target, this made life easy for some cases, but it wan't a very obvious gesture plus had other drawbacks with ordering of transformations (agg before join/lookup. after set and so forth) and supporting analytic SQL for example - there are a lot of postings from creative folks working around this in 11g - anything from customizing KMs, to bypassing aggregation analysis in the ODI code generator. The aggregate component has a few interesting aspects. 1. Firstly and foremost it defines the attributes projected from it - ODI automatically will perform the grouping all you do is define the aggregation expressions for those columns aggregated. In 12c you can control this automatic grouping behavior so that you get the code you desire, so you can indicate that an attribute should not be included in the group by, that's what I did in the analytic SQL example using the aggregate component. 2. The component has a few other properties of interest; it has a HAVING clause and a manual group by clause. The HAVING clause includes a predicate used to filter rows resulting from the GROUP BY clause. Because it acts on the results of the GROUP BY clause, aggregation functions can be used in the HAVING clause predicate, in 11g the filter was overloaded and used for both having clause and filter clause, this is no longer the case. If a filter is after an aggregate, it is after the aggregate (not sometimes after, sometimes having).  3. The manual group by clause let's you use special database grouping grammar if you need to. For example Oracle has a wealth of highly specialized grouping capabilities for data warehousing such as the CUBE function. If you want to use specialized functions like that you can manually define the code here. The example below shows the use of a manual group from an example in the Oracle database data warehousing guide where the SUM aggregate function is used along with the CUBE function in the group by clause. The SQL I am trying to generate looks like the following from the data warehousing guide; SELECT channel_desc, calendar_month_desc, countries.country_iso_code,       TO_CHAR(SUM(amount_sold), '9,999,999,999') SALES$ FROM sales, customers, times, channels, countries WHERE sales.time_id=times.time_id AND sales.cust_id=customers.cust_id AND   sales.channel_id= channels.channel_id  AND customers.country_id = countries.country_id  AND channels.channel_desc IN   ('Direct Sales', 'Internet') AND times.calendar_month_desc IN   ('2000-09', '2000-10') AND countries.country_iso_code IN ('GB', 'US') GROUP BY CUBE(channel_desc, calendar_month_desc, countries.country_iso_code); I can capture the source datastores, the filters and joins using ODI's dataset (or as a traditional flow) which enables us to incrementally design the mapping and the aggregate component for the sum and group by as follows; In the above mapping you can see the joins and filters declared in ODI's dataset, allowing you to capture the relationships of the datastores required in an entity-relationship style just like ODI 11g. The mix of ODI's declarative design and the common flow design provides for a familiar design experience. The example below illustrates flow design (basic arbitrary ordering) - a table load where only the employees who have maximum commission are loaded into a target. The maximum commission is retrieved from the bonus datastore and there is a look using employees as the driving table and only those with maximum commission projected. Hopefully this has given you a taster for some of the new capabilities provided by the aggregate component in ODI 12c. In summary, the actions should be much more consistent in behavior and more easily discoverable for users, the use of the components in a flow graph also supports arbitrary designs and the tool (rather than the interface designer) takes care of the realization using ODI's knowledge modules. Interested to know if a deep dive into each component is interesting for folks. Any thoughts? 

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• Can Kind People Finish First?

  - by Oracle Accelerate for Midsize Companies

  by Jim Lein, Oracle Midsize Programs In an earlier post, I expressed my undying love for KIND Snacks' products. This month's Oracle Profit magazine features an interview with KIND Healthy Snacks Founder and CEO Daniel Lubetzky entitled "Better Business". Lubetzky expresses his vision for making KIND a "not for profit only" company.  All great companies start with a good idea. In this case, that one great idea was to offer a healthy snack with ingredients you can "see and pronounce". That's one of things I really like about this company--that coupled with the fact that their snacks taste great. They compete in an over crowded playing field but I've found that it's rare to find an energy snack that both tastes good and is good for you.  A couple of interesting facts I learned from reading this article: 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-top:0in; mso-para-margin-right:0in; mso-para-margin-bottom:10.0pt; mso-para-margin-left:0in; line-height:115%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin;} 9 out of 10 consumers who try a KIND bar will purchase a KIND product again and recommend it to others KIND has the highest Net Promoter Score among the top 10 brands in the nutritional bar category (I confess I've never heard about this rating before but now that I have it's pretty cool) KIND's coporate mantra, "Do the Kind Thing" both encourages people to do random acts of kindness and provides easy mechanisms for doing so. Not coincidentally, I think, KIND is indeed a story about how nice guys can finish first. KIND has doubled in size every year for the last ten  years and now employees over 300 people, with sales exceeding $120M annually. Growth Applies Pressures One thing I know for certain from interacting our with fast growing customers over the last fifteen years is that growth applies myriad pressures across the organization--resources, processes, technology systems, and leadership agility. And it's easy to forget that Oracle was once an entrepreneurial startup and experienced all those same pressures that other growing companies are experiencing today. When asked by Profit Editor in Chief Aaron Lazenby, " What sort of pressure does KIND"s growth and success place on operations?", Lubetzky responded, "We have a demand planning process right now that is manual to a significant extent, and it just takes so much management time. It takes us days and sometimes weeks to produce information that is critical to our business—and by the time we get the results, we need revised data. Our sales leadership could go out selling, but instead they’re talking to our team about forecasts." Hitching Your Wagon to Oracle Lubetzky and his team selected Oracle for what I believe is our company's greatest strength: hitch your wagon to Oracle and you can trust that we will be there for the long run with the solutions you need and financial staying power. In Lubetzky's words, "The KIND philosophy requires you to have a long-term view of things; taking shortcuts may be the fastest way to get things done, but in the long term that can come back and bite you. Oracle is the type of company—and has the kind of platform—that is here for the long term. It’s not going to go away tomorrow. And Oracle is going to invest all the necessary resources into staying ahead of the game and improving." o next time you're in the supermarket or an REI (my favorite store in the world) or any of the other 80,000 locations that carry KIND, give one a try. Maybe some day you'll want to become a KIND Brand Ambassador.   Looking for more news and information about Oracle Solutions for Midsize Companies? Read the latest Oracle for Midsize Companies Newsletter Sign-up to receive the latest communications from Oracle’s industry leaders and experts Jim Lein I evangelize Oracle's enterprise solutions for growing midsize companies. I recently celebrated 15 years with Oracle, having joined JD Edwards in 1999. I'm based in Evergreen, Colorado and love relating stories about creativity and innovation whether they be about software, live music, or the mountains. The views expressed here are my own, and not necessarily those of Oracle.

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• Unexpected advantage of Engineered Systems

  - by user12244672

  It's not surprising that Engineered Systems accelerate the debugging and resolution of customer issues. But what has surprised me is just how much faster issue resolution is with Engineered Systems such as SPARC SuperCluster. These are powerful, complex, systems used by customers wanting extreme database performance, app performance, and cost saving server consolidation. A SPARC SuperCluster consists or 2 or 4 powerful T4-4 compute nodes, 3 or 6 extreme performance Exadata Storage Cells, a ZFS Storage Appliance 7320 for general purpose storage, and ultra fast Infiniband switches.  Each with its own firmware. It runs Solaris 11, Solaris 10, 11gR2, LDoms virtualization, and Zones virtualization on the T4-4 compute nodes, a modified version of Solaris 11 in the ZFS Storage Appliance, a modified and highly tuned version of Oracle Linux running Exadata software on the Storage Cells, another Linux derivative in the Infiniband switches, etc. It has an Infiniband data network between the components, a 10Gb data network to the outside world, and a 1Gb management network. And customers can run whatever middleware and apps they want on it, clustered in whatever way they want. In one word, powerful.  In another, complex. The system is highly Engineered.  But it's designed to run general purpose applications. That is, the physical components, configuration, cabling, virtualization technologies, switches, firmware, Operating System versions, network protocols, tunables, etc. are all preset for optimum performance and robustness. That improves the customer experience as what the customer runs leverages our technical know-how and best practices and is what we've tested intensely within Oracle. It should also make debugging easier by fixing a large number of variables which would otherwise be in play if a customer or Systems Integrator had assembled such a complex system themselves from the constituent components.  For example, there's myriad network protocols which could be used with Infiniband.  Myriad ways the components could be interconnected, myriad tunable settings, etc. But what has really surprised me - and I've been working in this area for 15 years now - is just how much easier and faster Engineered Systems have made debugging and issue resolution. All those error opportunities for sub-optimal cabling, unusual network protocols, sub-optimal deployment of virtualization technologies, issues with 3rd party storage, issues with 3rd party multi-pathing products, etc., are simply taken out of the equation. All those error opportunities for making an issue unique to a particular set-up, the "why aren't we seeing this on any other system ?" type questions, the doubts, just go away when we or a customer discover an issue on an Engineered System. It enables a really honed response, getting to the root cause much, much faster than would otherwise be the case. Here's a couple of examples from the last month, one found in-house by my team, one found by a customer: Example 1: We found a node eviction issue running 11gR2 with Solaris 11 SRU 12 under extreme load on what we call our ExaLego test system (mimics an Exadata / SuperCluster 11gR2 Exadata Storage Cell set-up).  We quickly established that an enhancement in SRU12 enabled an 11gR2 process to query Infiniband's Subnet Manager, replacing a fallback mechanism it had used previously.  Under abnormally heavy load, the query could return results which were misinterpreted resulting in node eviction.  In several daily joint debugging sessions between the Solaris, Infiniband, and 11gR2 teams, the issue was fully root caused, evaluated, and a fix agreed upon.  That fix went back into all Solaris releases the following Monday.  From initial issue discovery to the fix being put back into all Solaris releases was just 10 days. Example 2: A customer reported sporadic performance degradation.  The reasons were unclear and the information sparse.  The SPARC SuperCluster Engineered Systems support teams which comprises both SPARC/Solaris and Database/Exadata experts worked to root cause the issue.  A number of contributing factors were discovered, including tunable parameters.  An intense collaborative investigation between the engineering teams identified the root cause to a CPU bound networking thread which was being starved of CPU cycles under extreme load.  Workarounds were identified.  Modifications have been put back into 11gR2 to alleviate the issue and a development project already underway within Solaris has been sped up to provide the final resolution on the Solaris side.  The fixed SPARC SuperCluster configuration greatly aided issue reproduction and dramatically sped up root cause analysis, allowing the correct workarounds and fixes to be identified, prioritized, and implemented.  The customer is now extremely happy with performance and robustness.  Since the configuration is common to other customers, the lessons learned are being proactively rolled out to other customers and incorporated into the installation procedures for future customers.  This effectively acts as a turbo-boost to performance and reliability for all SPARC SuperCluster customers.  If this had occurred in a "home grown" system of this complexity, I expect it would have taken at least 6 months to get to the bottom of the issue.  But because it was an Engineered System, known, understood, and qualified by both the Solaris and Database teams, we were able to collaborate closely to identify cause and effect and expedite a solution for the customer.  That is a key advantage of Engineered Systems which should not be underestimated.  Indeed, the initial issue mitigation on the Database side followed by final fix on the Solaris side, highlights the high degree of collaboration and excellent teamwork between the Oracle engineering teams.  It's a compelling advantage of the integrated Oracle Red Stack in general and Engineered Systems in particular.

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• YouTube Scalability Lessons

  - by Bertrand Matthelié

  @font-face { font-family: "Arial"; }@font-face { font-family: "Courier New"; }@font-face { font-family: "Wingdings"; }@font-face { font-family: "Calibri"; }@font-face { font-family: "Cambria"; }p.MsoNormal, li.MsoNormal, div.MsoNormal { margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: "Times New Roman"; }h2 { margin: 12pt 0cm 3pt; page-break-after: avoid; font-size: 14pt; font-family: "Times New Roman"; font-style: italic; }a:link, span.MsoHyperlink { color: blue; text-decoration: underline; }a:visited, span.MsoHyperlinkFollowed { color: purple; text-decoration: underline; }span.Heading2Char { font-family: Calibri; font-weight: bold; font-style: italic; }div.Section1 { page: Section1; }ol { margin-bottom: 0cm; }ul { margin-bottom: 0cm; } Very interesting blog post by Todd Hoff at highscalability.com presenting “7 Years of YouTube Scalability Lessons in 30 min” based on a presentation from Mike Solomon, one of the original engineers at YouTube: …. The key takeaway away of the talk for me was doing a lot with really simple tools. While many teams are moving on to more complex ecosystems, YouTube really does keep it simple. They program primarily in Python, use MySQL as their database, they’ve stuck with Apache, and even new features for such a massive site start as a very simple Python program. That doesn’t mean YouTube doesn’t do cool stuff, they do, but what makes everything work together is more a philosophy or a way of doing things than technological hocus pocus. What made YouTube into one of the world’s largest websites? Read on and see... Stats @font-face { font-family: "Arial"; }@font-face { font-family: "Cambria"; }p.MsoNormal, li.MsoNormal, div.MsoNormal { margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: "Times New Roman"; }div.Section1 { page: Section1; } 4 billion Views a day 60 hours of video is uploaded every minute 350+ million devices are YouTube enabled Revenue double in 2010 The number of videos has gone up 9 orders of magnitude and the number of developers has only gone up two orders of magnitude. 1 million lines of Python code Stack @font-face { font-family: "Arial"; }@font-face { font-family: "Cambria"; }p.MsoNormal, li.MsoNormal, div.MsoNormal { margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: "Times New Roman"; }div.Section1 { page: Section1; } Python - most of the lines of code for YouTube are still in Python. Everytime you watch a YouTube video you are executing a bunch of Python code. Apache - when you think you need to get rid of it, you don’t. Apache is a real rockstar technology at YouTube because they keep it simple. Every request goes through Apache. Linux - the benefit of Linux is there’s always a way to get in and see how your system is behaving. No matter how bad your app is behaving, you can take a look at it with Linux tools like strace and tcpdump. MySQL - is used a lot. When you watch a video you are getting data from MySQL. Sometime it’s used a relational database or a blob store. It’s about tuning and making choices about how you organize your data. Vitess- a  new project released by YouTube, written in Go, it’s a frontend to MySQL. It does a lot of optimization on the fly, it rewrites queries and acts as a proxy. Currently it serves every YouTube database request. It’s RPC based. Zookeeper - a distributed lock server. It’s used for configuration. Really interesting piece of technology. Hard to use correctly so read the manual Wiseguy - a CGI servlet container. Spitfire - a templating system. It has an abstract syntax tree that let’s them do transformations to make things go faster. Serialization formats - no matter which one you use, they are all expensive. Measure. Don’t use pickle. Not a good choice. Found protocol buffers slow. They wrote their own BSON implementation, which is 10-15 time faster than the one you can download. ...Contiues. Read the blog Watch the video

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• Subterranean IL: The ThreadLocal type

  - by Simon Cooper

  I came across ThreadLocal<T> while I was researching ConcurrentBag. To look at it, it doesn't really make much sense. What's all those extra Cn classes doing in there? Why is there a GenericHolder<T,U,V,W> class? What's going on? However, digging deeper, it's a rather ingenious solution to a tricky problem. Thread statics Declaring that a variable is thread static, that is, values assigned and read from the field is specific to the thread doing the reading, is quite easy in .NET: [ThreadStatic] private static string s_ThreadStaticField; ThreadStaticAttribute is not a pseudo-custom attribute; it is compiled as a normal attribute, but the CLR has in-built magic, activated by that attribute, to redirect accesses to the field based on the executing thread's identity. TheadStaticAttribute provides a simple solution when you want to use a single field as thread-static. What if you want to create an arbitary number of thread static variables at runtime? Thread-static fields can only be declared, and are fixed, at compile time. Prior to .NET 4, you only had one solution - thread local data slots. This is a lesser-known function of Thread that has existed since .NET 1.1: LocalDataStoreSlot threadSlot = Thread.AllocateNamedDataSlot("slot1"); string value = "foo"; Thread.SetData(threadSlot, value); string gettedValue = (string)Thread.GetData(threadSlot); Each instance of LocalStoreDataSlot mediates access to a single slot, and each slot acts like a separate thread-static field. As you can see, using thread data slots is quite cumbersome. You need to keep track of LocalDataStoreSlot objects, it's not obvious how instances of LocalDataStoreSlot correspond to individual thread-static variables, and it's not type safe. It's also relatively slow and complicated; the internal implementation consists of a whole series of classes hanging off a single thread-static field in Thread itself, using various arrays, lists, and locks for synchronization. ThreadLocal<T> is far simpler and easier to use. ThreadLocal ThreadLocal provides an abstraction around thread-static fields that allows it to be used just like any other class; it can be used as a replacement for a thread-static field, it can be used in a List<ThreadLocal<T>>, you can create as many as you need at runtime. So what does it do? It can't just have an instance-specific thread-static field, because thread-static fields have to be declared as static, and so shared between all instances of the declaring type. There's something else going on here. The values stored in instances of ThreadLocal<T> are stored in instantiations of the GenericHolder<T,U,V,W> class, which contains a single ThreadStatic field (s_value) to store the actual value. This class is then instantiated with various combinations of the Cn types for generic arguments. In .NET, each separate instantiation of a generic type has its own static state. For example, GenericHolder<int,C0,C1,C2> has a completely separate s_value field to GenericHolder<int,C1,C14,C1>. This feature is (ab)used by ThreadLocal to emulate instance thread-static fields. Every time an instance of ThreadLocal is constructed, it is assigned a unique number from the static s_currentTypeId field using Interlocked.Increment, in the FindNextTypeIndex method. The hexadecimal representation of that number then defines the specific Cn types that instantiates the GenericHolder class. That instantiation is therefore 'owned' by that instance of ThreadLocal. This gives each instance of ThreadLocal its own ThreadStatic field through a specific unique instantiation of the GenericHolder class. Although GenericHolder has four type variables, the first one is always instantiated to the type stored in the ThreadLocal<T>. This gives three free type variables, each of which can be instantiated to one of 16 types (C0 to C15). This puts an upper limit of 4096 (163) on the number of ThreadLocal<T> instances that can be created for each value of T. That is, there can be a maximum of 4096 instances of ThreadLocal<string>, and separately a maximum of 4096 instances of ThreadLocal<object>, etc. However, there is an upper limit of 16384 enforced on the total number of ThreadLocal instances in the AppDomain. This is to stop too much memory being used by thousands of instantiations of GenericHolder<T,U,V,W>, as once a type is loaded into an AppDomain it cannot be unloaded, and will continue to sit there taking up memory until the AppDomain is unloaded. The total number of ThreadLocal instances created is tracked by the ThreadLocalGlobalCounter class. So what happens when either limit is reached? Firstly, to try and stop this limit being reached, it recycles GenericHolder type indexes of ThreadLocal instances that get disposed using the s_availableIndices concurrent stack. This allows GenericHolder instantiations of disposed ThreadLocal instances to be re-used. But if there aren't any available instantiations, then ThreadLocal falls back on a standard thread local slot using TLSHolder. This makes it very important to dispose of your ThreadLocal instances if you'll be using lots of them, so the type instantiations can be recycled. The previous way of creating arbitary thread-static variables, thread data slots, was slow, clunky, and hard to use. In comparison, ThreadLocal can be used just like any other type, and each instance appears from the outside to be a non-static thread-static variable. It does this by using the CLR type system to assign each instance of ThreadLocal its own instantiated type containing a thread-static field, and so delegating a lot of the bookkeeping that thread data slots had to do to the CLR type system itself! That's a very clever use of the CLR type system.

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• Navigation in a #WP7 application with MVVM Light

  - by Laurent Bugnion

  In MVVM applications, it can be a bit of a challenge to send instructions to the view (for example a page) from a viewmodel. Thankfully, we have good tools at our disposal to help with that. In his excellent series “MVVM Light Toolkit soup to nuts”, Jesse Liberty proposes one approach using the MVVM Light messaging infrastructure. While this works fine, I would like to show here another approach using what I call a “view service”, i.e. an abstracted service that is invoked from the viewmodel, and implemented on the view. Multiple kinds of view services In fact, I use view services quite often, and even started standardizing them for the Windows Phone 7 applications I work on. If there is interest, I will be happy to show other such view services, for example Animation services, responsible to start/stop animations on the view. Dialog service, in charge of displaying messages to the user and gathering feedback. Navigation service, in charge of navigating to a given page directly from the viewmodel. In this article, I will concentrate on the navigation service. The INavigationService interface In most WP7 apps, the navigation service is used in quite a straightforward way. We want to: Navigate to a given URI. Go back. Be notified when a navigation is taking place, and be able to cancel. The INavigationService interface is quite simple indeed: public interface INavigationService { event NavigatingCancelEventHandler Navigating; void NavigateTo(Uri pageUri); void GoBack(); } Obviously, this interface can be extended if necessary, but in most of the apps I worked on, I found that this covers my needs. The NavigationService class It is possible to nicely pack the navigation service into its own class. To do this, we need to remember that all the PhoneApplicationPage instances use the same instance of the navigation service, exposed through their NavigationService property. In fact, in a WP7 application, it is the main frame (RootFrame, of type PhoneApplicationFrame) that is responsible for this task. So, our implementation of the NavigationService class can leverage this. First the class will grab the PhoneApplicationFrame and store a reference to it. Also, it registers a handler for the Navigating event, and forwards the event to the listening viewmodels (if any). Then, the NavigateTo and the GoBack methods are implemented. They are quite simple, because they are in fact just a gateway to the PhoneApplicationFrame. The whole class is as follows: public class NavigationService : INavigationService { private PhoneApplicationFrame _mainFrame; public event NavigatingCancelEventHandler Navigating; public void NavigateTo(Uri pageUri) { if (EnsureMainFrame()) { _mainFrame.Navigate(pageUri); } } public void GoBack() { if (EnsureMainFrame() && _mainFrame.CanGoBack) { _mainFrame.GoBack(); } } private bool EnsureMainFrame() { if (_mainFrame != null) { return true; } _mainFrame = Application.Current.RootVisual as PhoneApplicationFrame; if (_mainFrame != null) { // Could be null if the app runs inside a design tool _mainFrame.Navigating += (s, e) => { if (Navigating != null) { Navigating(s, e); } }; return true; } return false; } } Exposing URIs I find that it is a good practice to expose each page’s URI as a constant. In MVVM Light applications, a good place to do that is the ViewModelLocator, which already acts like a central point of setup for the views and their viewmodels. Note that in some cases, it is necessary to expose the URL as a string, for instance when a query string needs to be passed to the view. So for example we could have: public static readonly Uri MainPageUri = new Uri("/MainPage.xaml", UriKind.Relative); public const string AnotherPageUrl = "/AnotherPage.xaml?param1={0}&param2={1}"; Creating and using the NavigationService Normally, we only need one instance of the NavigationService class. In cases where you use an IOC container, it is easy to simply register a singleton instance. For example, I am using a modified version of a super simple IOC container, and so I can register the navigation service as follows: SimpleIoc.Register<INavigationService, NavigationService>(); Then, it can be resolved where needed with: SimpleIoc.Resolve<INavigationService>(); Or (more frequently), I simply declare a parameter on the viewmodel constructor of type INavigationService and let the IOC container do its magic and inject the instance of the NavigationService when the viewmodel is created. On supported platforms (for example Silverlight 4), it is also possible to use MEF. Or, of course, we can simply instantiate the NavigationService in the ViewModelLocator, and pass this instance as a parameter of the viewmodels’ constructor, injected as a property, etc… Once the instance has been passed to the viewmodel, it can be used, for example with: NavigationService.NavigateTo(ViewModelLocator.ComparisonPageUri); Testing Thanks to the INavigationService interface, navigation can be mocked and tested when the viewmodel is put under unit test. Simply implement and inject a mock class, and assert that the methods are called as they should by the viewmodel. Conclusion As usual, there are multiple ways to code a solution answering your needs. I find that view services are a really neat way to delegate view-specific responsibilities such as animation, dialogs and of course navigation to other classes through an abstracted interface. In some cases, such as the NavigationService class exposed here, it is even possible to standardize the implementation and pack it in a class library for reuse. I hope that this sample is useful! Happy coding. Laurent   Laurent Bugnion (GalaSoft) Subscribe | Twitter | Facebook | Flickr | LinkedIn

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• Using XA Transactions in Coherence-based Applications

  - by jpurdy

  While the costs of XA transactions are well known (e.g. increased data contention, higher latency, significant disk I/O for logging, availability challenges, etc.), in many cases they are the most attractive option for coordinating logical transactions across multiple resources. There are a few common approaches when integrating Coherence into applications via the use of an application server's transaction manager: Use of Coherence as a read-only cache, applying transactions to the underlying database (or any system of record) instead of the cache. Use of TransactionMap interface via the included resource adapter. Use of the new ACID transaction framework, introduced in Coherence 3.6.   Each of these may have significant drawbacks for certain workloads. Using Coherence as a read-only cache is the simplest option. In this approach, the application is responsible for managing both the database and the cache (either within the business logic or via application server hooks). This approach also tends to provide limited benefit for many workloads, particularly those workloads that either have queries (given the complexity of maintaining a fully cached data set in Coherence) or are not read-heavy (where the cost of managing the cache may outweigh the benefits of reading from it). All updates are made synchronously to the database, leaving it as both a source of latency as well as a potential bottleneck. This approach also prevents addressing "hot data" problems (when certain objects are updated by many concurrent transactions) since most database servers offer no facilities for explicitly controlling concurrent updates. Finally, this option tends to be a better fit for key-based access (rather than filter-based access such as queries) since this makes it easier to aggressively invalidate cache entries without worrying about when they will be reloaded. The advantage of this approach is that it allows strong data consistency as long as optimistic concurrency control is used to ensure that database updates are applied correctly regardless of whether the cache contains stale (or even dirty) data. Another benefit of this approach is that it avoids the limitations of Coherence's write-through caching implementation. TransactionMap is generally used when Coherence acts as system of record. TransactionMap is not generally compatible with write-through caching, so it will usually be either used to manage a standalone cache or when the cache is backed by a database via write-behind caching. TransactionMap has some restrictions that may limit its utility, the most significant being: The lock-based concurrency model is relatively inefficient and may introduce significant latency and contention. As an example, in a typical configuration, a transaction that updates 20 cache entries will require roughly 40ms just for lock management (assuming all locks are granted immediately, and excluding validation and writing which will require a similar amount of time). This may be partially mitigated by denormalizing (e.g. combining a parent object and its set of child objects into a single cache entry), at the cost of increasing false contention (e.g. transactions will conflict even when updating different child objects). If the client (application server JVM) fails during the commit phase, locks will be released immediately, and the transaction may be partially committed. In practice, this is usually not as bad as it may sound since the commit phase is usually very short (all locks having been previously acquired). Note that this vulnerability does not exist when a single NamedCache is used and all updates are confined to a single partition (generally implying the use of partition affinity). The unconventional TransactionMap API is cumbersome but manageable. Only a few methods are transactional, primarily get(), put() and remove(). The ACID transactions framework (accessed via the Connection class) provides atomicity guarantees by implementing the NamedCache interface, maintaining its own cache data and transaction logs inside a set of private partitioned caches. This feature may be used as either a local transactional resource or as logging XA resource. However, a lack of database integration precludes the use of this functionality for most applications. A side effect of this is that this feature has not seen significant adoption, meaning that any use of this is subject to the usual headaches associated with being an early adopter (greater chance of bugs and greater risk of hitting an unoptimized code path). As a result, for the moment, we generally recommend against using this feature. In summary, it is possible to use Coherence in XA-oriented applications, and several customers are doing this successfully, but it is not a core usage model for the product, so care should be taken before committing to this path. For most applications, the most robust solution is normally to use Coherence as a read-only cache of the underlying data resources, even if this prevents taking advantage of certain product features.

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• Using Subjects to Deploy Queries Dynamically

  - by Roman Schindlauer

  In the previous blog posting, we showed how to construct and deploy query fragments to a StreamInsight server, and how to re-use them later. In today’s posting we’ll integrate this pattern into a method of dynamically composing a new query with an existing one. The construct that enables this scenario in StreamInsight V2.1 is a Subject. A Subject lets me create a junction element in an existing query that I can tap into while the query is running. To set this up as an end-to-end example, let’s first define a stream simulator as our data source: var generator = myApp.DefineObservable(     (TimeSpan t) => Observable.Interval(t).Select(_ => new SourcePayload())); This ‘generator’ produces a new instance of SourcePayload with a period of t (system time) as an IObservable. SourcePayload happens to have a property of type double as its payload data. Let’s also define a sink for our example—an IObserver of double values that writes to the console: var console = myApp.DefineObserver(     (string label) => Observer.Create<double>(e => Console.WriteLine("{0}: {1}", label, e)))     .Deploy("ConsoleSink"); The observer takes a string as parameter which is used as a label on the console, so that we can distinguish the output of different sink instances. Note that we also deploy this observer, so that we can retrieve it later from the server from a different process. Remember how we defined the aggregation as an IQStreamable function in the previous article? We will use that as well: var avg = myApp     .DefineStreamable((IQStreamable<SourcePayload> s, TimeSpan w) =>         from win in s.TumblingWindow(w)         select win.Avg(e => e.Value))     .Deploy("AverageQuery"); Then we define the Subject, which acts as an observable sequence as well as an observer. Thus, we can feed a single source into the Subject and have multiple consumers—that can come and go at runtime—on the other side: var subject = myApp.CreateSubject("Subject", () => new Subject<SourcePayload>()); Subject are always deployed automatically. Their name is used to retrieve them from a (potentially) different process (see below). Note that the Subject as we defined it here doesn’t know anything about temporal streams. It is merely a sequence of SourcePayloads, without any notion of StreamInsight point events or CTIs. So in order to compose a temporal query on top of the Subject, we need to 'promote' the sequence of SourcePayloads into an IQStreamable of point events, including CTIs: var stream = subject.ToPointStreamable(     e => PointEvent.CreateInsert<SourcePayload>(e.Timestamp, e),     AdvanceTimeSettings.StrictlyIncreasingStartTime); In a later posting we will show how to use Subjects that have more awareness of time and can be used as a junction between QStreamables instead of IQbservables. Having turned the Subject into a temporal stream, we can now define the aggregate on this stream. We will use the IQStreamable entity avg that we defined above: var longAverages = avg(stream, TimeSpan.FromSeconds(5)); In order to run the query, we need to bind it to a sink, and bind the subject to the source: var standardQuery = longAverages     .Bind(console("5sec average"))     .With(generator(TimeSpan.FromMilliseconds(300)).Bind(subject)); Lastly, we start the process: standardQuery.Run("StandardProcess"); Now we have a simple query running end-to-end, producing results. What follows next is the crucial part of tapping into the Subject and adding another query that runs in parallel, using the same query definition (the “AverageQuery”) but with a different window length. We are assuming that we connected to the same StreamInsight server from a different process or even client, and thus have to retrieve the previously deployed entities through their names: // simulate the addition of a 'fast' query from a separate server connection, // by retrieving the aggregation query fragment // (instead of simply using the 'avg' object) var averageQuery = myApp     .GetStreamable<IQStreamable<SourcePayload>, TimeSpan, double>("AverageQuery"); // retrieve the input sequence as a subject var inputSequence = myApp     .GetSubject<SourcePayload, SourcePayload>("Subject"); // retrieve the registered sink var sink = myApp.GetObserver<string, double>("ConsoleSink"); // turn the sequence into a temporal stream var stream2 = inputSequence.ToPointStreamable(     e => PointEvent.CreateInsert<SourcePayload>(e.Timestamp, e),     AdvanceTimeSettings.StrictlyIncreasingStartTime); // apply the query, now with a different window length var shortAverages = averageQuery(stream2, TimeSpan.FromSeconds(1)); // bind new sink to query and run it var fastQuery = shortAverages     .Bind(sink("1sec average"))     .Run("FastProcess"); The attached solution demonstrates the sample end-to-end. Regards, The StreamInsight Team

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• UIViewAnimation done by a UIViewController belonging to a UINavigationController?

  - by RickiG

  Hi I have an UINavigationController which the user navigates with. When pushing a specific UIViewController onto the navigation stack, a "settings" button appear in the navigationBar. When the user clicks this button I would like to flip the current view/controller, i.e. everything on screen, including the navigationBar, over to a settings view. So I have a SettingsViewController which I would like to flip to from my CurrentViewController that lives on a navigationController stack. I get all kinds of strange behavior trying to do this, the UIViews belonging to the SettingsViewController will start to animate, sliding into place, the navigationButtons moves around, nothing acts as I would think. -(void)settingsHandler { SettingViewController *settingsView = [[SettingViewController alloc] init]; [UIView beginAnimations:nil context:nil]; [UIView setAnimationDuration:1.0]; [UIView setAnimationTransition:UIViewAnimationTransitionFlipFromRight forView:self.navigationController.view cache:YES]; [self.navigationController.view addSubview:settingsView.view]; [UIView commitAnimations]; } The above results in the views flipping correctly, but the subviews of the SettingsViewController are all positioned in (0, 0) and after the transition, they 'snap' into place? Is it because I instantiate and add my subviews in viewDidLoad, like this? - (void)viewDidLoad { UIImageView *imageBg = [[UIImageView alloc] initWithFrame:CGRectMake(0.0f, 0.0f, 320.0f, 460.0f)]; [imageBg setImage:[UIImage imageNamed:@"background.png"]]; [self.view addSubview:imageBg]; [imageBg release]; SettingsSubview *switchView = [[SettingsSubview alloc] initWithFrame:CGRectMake(0.0f, 0.0f, 320.0f, 460.0f)]; [self.view addSubview:switchView]; [switchView release]; [super viewDidLoad]; } 1: How should I correctly do the "flip" transition, from within the UIViewController in the UINavigationController, to a new UIViewController and subsequently from the new UIViewController and back to the "original" UIViewController residing on the UINavigationControllers stack? 2: Should I use a different approach, than the "viewDidLoad" method, when instantiating and adding subviews to a UIViewController? -question 2 is more of a "best practice" thing. I have seen different ways of doing it and I am having trouble either finding or understanding the life-cycle documentation and the different threads and posts on the subject. I am missing the "best practice" examples. Thank You very much for any help given:)

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• mysql never releases memory

  - by Ishu

  I have a production server clocking about 4 million page views per month. The server has got 8GB of RAM and mysql acts as a database. I am facing problems in handling mysql to take this load. I need to restart mysql twice a day to handle this thing. The problem with mysql is that it starts with some particular occupation, the memory consumed by mysql keeps on increasing untill it reaches the maximum it can consume and then mysql stops responding slowly or does not respond at all, which freezes the server. All my tables are indexed properly and there are no long queries. I need some one to help on how to go about debugging what to do here. All my tables are myisam. I have tried configuring the parameters key_buffer etc but to no rescue. Any sort of help is greatly appreciated. Here are some parameters which may help. mysql --version mysql Ver 14.12 Distrib 5.0.77, for redhat-linux-gnu (i686) using readline 5.1 mysql> show variables; +---------------------------------+------------------------------------------------------------+ | Variable_name | Value | +---------------------------------+------------------------------------------------------------+ | auto_increment_increment | 1 | | auto_increment_offset | 1 | | automatic_sp_privileges | ON | | back_log | 50 | | basedir | /usr/ | | bdb_cache_size | 8384512 | | bdb_home | /var/lib/mysql/ | | bdb_log_buffer_size | 262144 | | bdb_logdir | | | bdb_max_lock | 10000 | | bdb_shared_data | OFF | | bdb_tmpdir | /tmp/ | | binlog_cache_size | 32768 | | bulk_insert_buffer_size | 8388608 | | character_set_client | latin1 | | character_set_connection | latin1 | | character_set_database | latin1 | | character_set_filesystem | binary | | character_set_results | latin1 | | character_set_server | latin1 | | character_set_system | utf8 | | character_sets_dir | /usr/share/mysql/charsets/ | | collation_connection | latin1_swedish_ci | | collation_database | latin1_swedish_ci | | collation_server | latin1_swedish_ci | | completion_type | 0 | | concurrent_insert | 1 | | connect_timeout | 10 | | datadir | /var/lib/mysql/ | | date_format | %Y-%m-%d | | datetime_format | %Y-%m-%d %H:%i:%s | | default_week_format | 0 | | delay_key_write | ON | | delayed_insert_limit | 100 | | delayed_insert_timeout | 300 | | delayed_queue_size | 1000 | | div_precision_increment | 4 | | keep_files_on_create | OFF | | engine_condition_pushdown | OFF | | expire_logs_days | 0 | | flush | OFF | | flush_time | 0 | | ft_boolean_syntax | + -><()~*:""&| | | ft_max_word_len | 84 | | ft_min_word_len | 4 | | ft_query_expansion_limit | 20 | | ft_stopword_file | (built-in) | | group_concat_max_len | 1024 | | have_archive | NO | | have_bdb | YES | | have_blackhole_engine | NO | | have_compress | YES | | have_crypt | YES | | have_csv | NO | | have_dynamic_loading | YES | | have_example_engine | NO | | have_federated_engine | NO | | have_geometry | YES | | have_innodb | YES | | have_isam | NO | | have_merge_engine | YES | | have_ndbcluster | NO | | have_openssl | DISABLED | | have_ssl | DISABLED | | have_query_cache | YES | | have_raid | NO | | have_rtree_keys | YES | | have_symlink | YES | | | init_connect | | | init_file | | | init_slave | | | interactive_timeout | 28800 | | join_buffer_size | 131072 | | key_buffer_size | 2621440000 | | key_cache_age_threshold | 300 | | key_cache_block_size | 1024 | | key_cache_division_limit | 100 | | language | /usr/share/mysql/english/ | | large_files_support | ON | | large_page_size | 0 | | large_pages | OFF | | lc_time_names | en_US | | license | GPL | | local_infile | ON | | locked_in_memory | OFF | | log | OFF | | log_bin | ON | | log_bin_trust_function_creators | OFF | | log_error | | | log_queries_not_using_indexes | OFF | | log_slave_updates | OFF | | log_slow_queries | ON | | log_warnings | 1 | | long_query_time | 8 | | low_priority_updates | OFF | | lower_case_file_system | OFF | | lower_case_table_names | 0 | | max_allowed_packet | 8388608 | | max_binlog_cache_size | 4294963200 | | max_binlog_size | 1073741824 | | max_connect_errors | 10 | | max_connections | 400 | | max_delayed_threads | 20 | | max_error_count | 64 | | max_heap_table_size | 16777216 | | max_insert_delayed_threads | 20 | | max_join_size | 4294967295 | | max_length_for_sort_data | 1024 | | max_prepared_stmt_count | 16382 | | max_relay_log_size | 0 | | max_seeks_for_key | 4294967295 | | max_sort_length | 1024 | | max_sp_recursion_depth | 0 | | max_tmp_tables | 32 | | max_user_connections | 0 | | max_write_lock_count | 4294967295 | | multi_range_count | 256 | | myisam_data_pointer_size | 6 | | myisam_max_sort_file_size | 2146435072 | | myisam_recover_options | OFF | | myisam_repair_threads | 1 | | myisam_sort_buffer_size | 16777216 | | myisam_stats_method | nulls_unequal | | net_buffer_length | 16384 | | net_read_timeout | 30 | | net_retry_count | 10 | | net_write_timeout | 60 | | new | OFF | | old_passwords | OFF | | open_files_limit | 2000 | | optimizer_prune_level | 1 | | optimizer_search_depth | 62 | | pid_file | /var/run/mysqld/mysqld.pid | | plugin_dir | | | port | 3306 | | preload_buffer_size | 32768 | | profiling | OFF | | profiling_history_size | 15 | | protocol_version | 10 | | query_alloc_block_size | 8192 | | query_cache_limit | 1048576 | | query_cache_min_res_unit | 4096 | | query_cache_size | 134217728 | | query_cache_type | ON | | query_cache_wlock_invalidate | OFF | | query_prealloc_size | 8192 | | range_alloc_block_size | 4096 | | read_buffer_size | 2097152 | | read_only | OFF | | read_rnd_buffer_size | 8388608 | | relay_log | | | relay_log_index | | | relay_log_info_file | relay-log.info | | relay_log_purge | ON | | relay_log_space_limit | 0 | | rpl_recovery_rank | 0 | | secure_auth | OFF | | secure_file_priv | | | server_id | 1 | | skip_external_locking | ON | | skip_networking | OFF | | skip_show_database | OFF | | slave_compressed_protocol | OFF | | slave_load_tmpdir | /tmp/ | | slave_net_timeout | 3600 | | slave_skip_errors | OFF | | slave_transaction_retries | 10 | | slow_launch_time | 2 | | socket | /var/lib/mysql/mysql.sock | | sort_buffer_size | 2097152 | | sql_big_selects | ON | | sql_mode | | | sql_notes | ON | | sql_warnings | OFF | | ssl_ca | | | ssl_capath | | | ssl_cert | | | ssl_cipher | | | ssl_key | | | storage_engine | MyISAM | | sync_binlog | 0 | | sync_frm | ON | | system_time_zone | CST | | table_cache | 256 | | table_lock_wait_timeout | 50 | | table_type | MyISAM | | thread_cache_size | 8 | | thread_stack | 196608 | | time_format | %H:%i:%s | | time_zone | SYSTEM | | timed_mutexes | OFF | | tmp_table_size | 33554432 | | tmpdir | /tmp/ | | transaction_alloc_block_size | 8192 | | transaction_prealloc_size | 4096 | | tx_isolation | REPEATABLE-READ | | updatable_views_with_limit | YES | | version | 5.0.77-log | | version_bdb | Sleepycat Software: Berkeley DB 4.1.24: (January 29, 2009) | | version_comment | Source distribution | | version_compile_machine | i686 | | version_compile_os | redhat-linux-gnu | | wait_timeout | 28800 | +---------------------------------+------------------------------------------------------------+

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• impersonation and BackgroundWorker

  - by Lucian D

  Hello guys, I have a little bit of a problem when trying to use the BackgroundWorker class with impersonation. Following the answers from google, I got this code to impersonate public class MyImpersonation{ WindowsImpersonationContext impersonationContext; [DllImport("advapi32.dll")] public static extern int LogonUserA(String lpszUserName, String lpszDomain, String lpszPassword, int dwLogonType, int dwLogonProvider, ref IntPtr phToken); [DllImport("advapi32.dll", CharSet = CharSet.Auto, SetLastError = true)] public static extern int DuplicateToken(IntPtr hToken, int impersonationLevel, ref IntPtr hNewToken); [DllImport("advapi32.dll", CharSet = CharSet.Auto, SetLastError = true)] public static extern bool RevertToSelf(); [DllImport("kernel32.dll", CharSet = CharSet.Auto)] public static extern bool CloseHandle(IntPtr handle); public bool impersonateValidUser(String userName, String domain, String password) { WindowsIdentity tempWindowsIdentity; IntPtr token = IntPtr.Zero; IntPtr tokenDuplicate = IntPtr.Zero; if (RevertToSelf()) { if (LogonUserA(userName, domain, password, LOGON32_LOGON_INTERACTIVE, LOGON32_PROVIDER_DEFAULT, ref token) != 0) { if (DuplicateToken(token, 2, ref tokenDuplicate) != 0) { tempWindowsIdentity = new WindowsIdentity(tokenDuplicate); impersonationContext = tempWindowsIdentity.Impersonate(); if (impersonationContext != null) { CloseHandle(token); CloseHandle(tokenDuplicate); return true; } } } } if (token != IntPtr.Zero) CloseHandle(token); if (tokenDuplicate != IntPtr.Zero) CloseHandle(tokenDuplicate); return false; } } It worked really well until I've used it with the BackgroundWorker class. In this case, I've added a impersonation in the the code that runs asynchronously. I have no errors, but the issue I'm having is that the impersonation does not work when it is used in the async method. In code this looks something like this: instantiate a BGWorker, and add an event handler to the DoWork event: _bgWorker = new BackgroundWorker(); _bgWorker.DoWork += new DoWorkEventHandler(_bgWorker_DoWork); in the above handler, a impersonation is made before running some code. private void _bgWorker_DoWork(object sender, DoWorkEventArgs e) { MyImpersonation myImpersonation = new MyImpersonation(); myImpersonation.impersonateValidUser(user, domain, pass) //run some code... myImpersonation.undoImpersonation(); } the code is launched with BGWorker.RunWorkerAsync(); As I said before, no error is thrown, only that the code acts as if I did't run any impersonation, that is with it's default credentials. Moreover, the impersonation method returns true, so the impersonation took place at a certain level, but probably not on the current thread. This must happen because the async code runs on another thread, so there must be something that needs to be added to the MyImpersonation class. But what?? :) Thanks in advance, Lucian

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• UIScrollView works as expected but scrollRectToVisible: does nothing

  - by mahboudz

  HI. I have used UIScrollView before, and am using it now, and never had a problem. I'm now adding it to an old app, and while it works as expected (I can look at the contents, scroll around with my finger, all the bounds and sizes are setup right so there is no empty space in the content, etc.), I just can't get scrollToRectVisible to work. I have even simplified the call so that it merely moves to the 0,0 position: [scrollView scrollRectToVisible:CGRectMake(0, 0, 10, 10) animated:YES]; or move it to 0,200: [scrollView scrollRectToVisible:CGRectMake(0, 200, 10, 10) animated:YES]; I even made a quick app to test this and I can get scrollRectToVisible to work there as I expect. But in my old app, I can't seem to make it do anything. I can make the scrollView scroll with setContentOffset:, but that's not what I want. This scrollView and its contents are defined in the nib by IB and used with an IBOutlet. The only code I am using in my app to handle the scrollView is [scrollView setContentSize:CGSizeMake(scrollView.contentSize.width, imageView.frame.size.height)]; (I'm only interested in vertical scrolling not horizontal). Has anyone run into a problem like this? I have compared the scrollView attributes in both apps and they are identical. ADDENDUM: My scrollViews frame is: 0.000000 0.000000 480.000000 179.000000 My scrollViews contentSize is: 0.000000 324.000000 It still acts like the rect I want to scroll to is already visible and no scrolling is needed. Not sure if that is what is happening. This is just the darnest thing. Seems like such an easy thing to resolve... ADDENDUM #2: This is how I am making do without scrollRectToVisible: CGPoint point = myRect.origin; if (![clefScrollView pointInside:point withEvent:nil]) { point.x = 0; if (point.y > clefScrollView.contentSize.height - clefScrollView.bounds.size.height) point.y = clefScrollView.contentSize.height - clefScrollView.bounds.size.height; [clefScrollView setContentOffset:point animated: YES]; } Everything else about this scrollView works as expected, but scrollRectToVisible. WHY?!? Any wild guesses?

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