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  • ruby on rails configuration

    - by Themasterhimself
    Im using the following guide for getting started with rails for ubuntu 9.10. http://guides.rails.info/getting_started.html I have installed both ruby and gem. gokul@gokul-laptop:~$ ruby -v ruby 1.8.7 (2009-06-12 patchlevel 174) [i486-linux] gokul@gokul-laptop:~$ gem -v 1.3.6 gokul@gokul-laptop:~$ For rails, gokul@gokul-laptop:~$sudo gem install rails doesnt seem to give any response. so used the synaptic package manager for installing it. And it seems to have installed correctly. gokul@gokul-laptop:~$ rails Usage: /usr/bin/rails /path/to/your/app [options] Options: -r, --ruby=path Path to the Ruby binary of your choice (otherwise scripts use env, dispatchers current path). Default: /usr/bin/ruby1.8 -d, --database=name Preconfigure for selected database (options: mysql/oracle/postgresql/sqlite2/sqlite3/frontbase/ibm_db). Default: sqlite3 -D, --with-dispatchers Add CGI/FastCGI/mod_ruby dispatches code to generated application skeleton Default: false --freeze Freeze Rails in vendor/rails from the gems generating the skeleton Default: false -m, --template=path Use an application template that lives at path (can be a filesystem path or URL). Default: (none) Rails Info: -v, --version Show the Rails version number and quit. -h, --help Show this help message and quit. General Options: -p, --pretend Run but do not make any changes. -f, --force Overwrite files that already exist. -s, --skip Skip files that already exist. -q, --quiet Suppress normal output. -t, --backtrace Debugging: show backtrace on errors. -c, --svn Modify files with subversion. (Note: svn must be in path) -g, --git Modify files with git. (Note: git must be in path) Description: The 'rails' command creates a new Rails application with a default directory structure and configuration at the path you specify. Example: rails ~/Code/Ruby/weblog This generates a skeletal Rails installation in ~/Code/Ruby/weblog. See the README in the newly created application to get going. gokul@gokul-laptop:~$ app folder is created with all the proper folders. The problem starts with the following commands... gokul@gokul-laptop:~$ sudo gem install bundler [sudo] password for gokul: Successfully installed bundler-0.9.24 1 gem installed Installing ri documentation for bundler-0.9.24... Installing RDoc documentation for bundler-0.9.24... gokul@gokul-laptop:~$ bundle install Could not locate Gemfile gokul@gokul-laptop:~$ coming to the database, the default sqlite3 seems to have installed correctly. gokul@gokul-laptop:~$ sqlite3 SQLite version 3.6.16 Enter ".help" for instructions Enter SQL statements terminated with a ";" sqlite The welcome aboard page is not being able to be found at (http://localhost:3000) after executing the following commands... gokul@gokul-laptop:~/Desktop$ rails blog create create app/controllers create app/helpers create app/models create app/views/layouts create config/environments create config/initializers create config/locales create db create doc create lib create lib/tasks create log create public/images create public/javascripts create public/stylesheets create script/performance create test/fixtures create test/functional create test/integration create test/performance create test/unit create vendor create vendor/plugins create tmp/sessions create tmp/sockets create tmp/cache create tmp/pids create Rakefile create README create app/controllers/application_controller.rb create app/helpers/application_helper.rb create config/database.yml create config/routes.rb create config/locales/en.yml create db/seeds.rb create config/initializers/backtrace_silencers.rb create config/initializers/inflections.rb create config/initializers/mime_types.rb create config/initializers/new_rails_defaults.rb create config/initializers/session_store.rb create config/environment.rb create config/boot.rb create config/environments/production.rb create config/environments/development.rb create config/environments/test.rb create script/about create script/console create script/dbconsole create script/destroy create script/generate create script/runner create script/server create script/plugin create script/performance/benchmarker create script/performance/profiler create test/test_helper.rb create test/performance/browsing_test.rb create public/404.html create public/422.html create public/500.html create public/index.html create public/favicon.ico create public/robots.txt create public/images/rails.png create public/javascripts/prototype.js create public/javascripts/effects.js create public/javascripts/dragdrop.js create public/javascripts/controls.js create public/javascripts/application.js create doc/README_FOR_APP create log/server.log create log/production.log create log/development.log create log/test.log gokul@gokul-laptop:~/Desktop$ cd blog gokul@gokul-laptop:~/Desktop/blog$ rake db:create (in /home/gokul/Desktop/blog) gokul@gokul-laptop:~/Desktop/blog$ rails server create create app/controllers create app/helpers create app/models create app/views/layouts create config/environments create config/initializers create config/locales create db create doc create lib create lib/tasks create log create public/images create public/javascripts create public/stylesheets create script/performance create test/fixtures create test/functional create test/integration create test/performance create test/unit create vendor create vendor/plugins create tmp/sessions create tmp/sockets create tmp/cache create tmp/pids create Rakefile create README create app/controllers/application_controller.rb create app/helpers/application_helper.rb create config/database.yml create config/routes.rb create config/locales/en.yml create db/seeds.rb create config/initializers/backtrace_silencers.rb create config/initializers/inflections.rb create config/initializers/mime_types.rb create config/initializers/new_rails_defaults.rb create config/initializers/session_store.rb create config/environment.rb create config/boot.rb create config/environments/production.rb create config/environments/development.rb create config/environments/test.rb create script/about create script/console create script/dbconsole create script/destroy create script/generate create script/runner create script/server create script/plugin create script/performance/benchmarker create script/performance/profiler create test/test_helper.rb create test/performance/browsing_test.rb create public/404.html create public/422.html create public/500.html create public/index.html create public/favicon.ico create public/robots.txt create public/images/rails.png create public/javascripts/prototype.js create public/javascripts/effects.js create public/javascripts/dragdrop.js create public/javascripts/controls.js create public/javascripts/application.js create doc/README_FOR_APP create log/server.log create log/production.log create log/development.log create log/test.log gokul@gokul-laptop:~/Desktop/blog$ hope some one can help me with this...

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  • top Tweets SOA Partner Community – August 2012

    - by JuergenKress
    Send your tweets @soacommunity #soacommunity and follow us at http://twitter.com/soacommunity Lucas Jellema ?Published an article about organizing Fusion Middleware Administration: http://technology.amis.nl/2012/07/31/organizing-fusion-middleware-administration-in-a-smart-and-frugal-way … - many organizations are struggling with this. ServiceTechSymposium Countdown to the Early Bird Registration Discount deadline. Only 4 days left! http://ow.ly/cBCiv demed ?Good chatting w Bob Rhubart, Thomas Erl & Tim Hall on SOA & Cloud Symposium https://blogs.oracle.com/archbeat/entry/podcast_show_notes_thomas_erl … @soaschool @OTNArchBeat -- CU in London! SOA Community top Tweets SOA Partner Community July 2012 - are you one of them? If yes please rt! https://soacommunity.wordpress.com/2012/07/30/top-tweets-soa-partner-community-july-2012/ … #soacommunity SOA Community ?Are You a facebook member - do You follow http://www.facebook.com/soacommunity ? #soacommunity #soa SOA Community ?SOA 24/7 - Home Page: http://soa247.com/#.UBJsN8n3kyk.twitter … #soacommunity OracleBlogs ?Handling Large Payloads in SOA Suite 11g http://ow.ly/1lFAih OracleBlogs ?SOA Community Newsletter July 2012 http://ow.ly/1lFx6s OTNArchBeat Podcast Show Notes: Thomas Erl on SOA, Cloud, and Service Technology http://bit.ly/OOHTUJ SOA Community SOA Community Newsletter July 2012 http://wp.me/p10C8u-s7 OTNArchBeat ?OTN ArchBeat Podcast: Thomas Erl on SOA, Cloud, and Service Technology - Part 1 http://pub.vitrue.com/fMti OProcessAccel ?Just released! White Paper: Oracle Process Accelerators Best Practices http://www.oracle.com/technetwork/middleware/bpm/learnmore/processaccelbestpracticeswhitepaper-1708910.pdf … OTNArchBeat ?SOA, Cloud, and Service Technologies - Part 1 of 4 - A conversation with SOA, Cloud, and Service Technology Symposiu... http://ow.ly/1lDyAK OracleBlogs ?SOA Suite 11g PS5 Bundled Patch 3 (11.1.1.6.3) http://ow.ly/1lCW1S Simon Haslam My write-up of the virtues of the #ukoug App Server & Middleware SIG http://bit.ly/LMWdfY What's important to you for our next meeting? SOA Community SOA Partner Community Survey 2012 http://wp.me/p10C8u-qY Simone Geib ?RT @jswaroop: #Oracle positioned in the Leader's quadrant - Gartner Magic Quadrants for Application Infrastructure (SOA & SOA Gov)... ServiceTechSymposium New Supporting Organization, IBTI has joined the Symposium! http://www.servicetechsymposium.com/ orclateamsoa ?A-Team Blog #ateam: BPM 11g Task Form Version Considerations http://ow.ly/1lA7XS OTNArchBeat Oracle content at SOA, Cloud and Service Technology Symposium (and discount code!) http://pub.vitrue.com/FPcW OracleBlogs ?BPM 11g Task Form Version Considerations http://ow.ly/1lzOrX OTNArchBeat BPM 11g #ADF Task Form Versioning | Christopher Karl Chan #fusionmiddleware http://pub.vitrue.com/0qP2 OTNArchBeat Lightweight ADF Task Flow for BPM Human Tasks Overview | @AndrejusB #fusionmiddleware http://pub.vitrue.com/z7x9 SOA Community Oracle Fusion Middleware Summer Camps in Lisbon report by Link Consulting http://middlewarebylink.wordpress.com/2012/07/20/oracle-fusion-middleware-summer-camps-in-lisbon/ … #ofmsummercamps #soa #bpm SOA Community ?Clemens Utschig-Utschig & Manas Deb The Successful Execution of the SOA and BPM Vision Using a Business Capability Framework: Concepts… Simone Geib ?RT @oprocessaccel: Just released! White Paper: Oracle Process Accelerators Best Practices http://www.oracle.com/technetwork/middleware/bpm/learnmore/processaccelbestpracticeswhitepaper-1708910.pdf … jornica ?Report from Oracle Fusion Middleware Summer Camps in Munich: SOA Suite 11g advanced training experiences @soacommunity http://bit.ly/Mw3btE Simone Geib ?Bruce Tierney: Update - SOA & BPM Customer Insights Webcast Series: | https://blogs.oracle.com/SOA/entry/update_soa_bpm_customer_insights … OTNArchBeat Business SOA: Thinking is Dead | @mosesjones http://pub.vitrue.com/k8mw esentri ?had 3 great days in Munich at #Oracle #soacommunity Summercamp! Special thanks to Geoffroy de Lamalle from eProseed! Danilo Schmiedel ?Used my time in train to setup the ps5 soa/bpm vbox-image.Works like a dream. Setup-Readme is perfect! Saves a lot of time!!! @soacommunity 18 Jul SOA Community ?THANKS for the excellent OFM summer camps - save trip home - share your pictures at http://www.facebook.com/soacommunity #ofmsummercamps #soacommunity doors BBQ-party with Oracle @soacommunity. 5Star! #lovemunich #ofmsummercamps pic.twitter.com/ztfcGn2S leonsmiers ?New #Capgemini blog post "Continuous Improvement of Business Agility" http://bit.ly/Lr0EwG #bpm #yam Eric Elzinga ?MDS Explorer utility, http://see.sc/4qdb43 #soasuite ServiceTechSymposium ?@techsymp New speaker Demed L’Her from Oracle has been added to the symposium calendar. http://ow.ly/cjnyw SOA Community ?Last day of the Fusion Middleware summer camps - we continue at 9.00 am. send us your barbecue pictures! #ofmsummercamps #soacommunity SOA Community ?Delivering SOA Governance with EAMS and Oracle Enterprise Repository by Link Consulting http://middlewarebylink.wordpress.com/2012/06/26/delivering-soa-governance-with-eams-and-oracle-enterprise-repository/ … #soacommunity #soa #oer OracleBlogs ?Process Accelerator Kit http://ow.ly/1loaCw 15 Jul SOA Community ?Sun is back in Munich! Send your pictures Middleware summer camps! #ofmsummercamps We start tomorrow 11.00 at Oracle pic.twitter.com/6FStxomk Walter Montantes ?Gracias, Obrigado, Thank you, Danke a Lisboa y a @soacommunity @wlscommunity. From the Mexican guys!! cc @mikeintoch #ofmsummercamps Andrejus Baranovskis Tips & Tricks How to Run Oracle BPM 11g PS5 Workspace from Custom ADF 11g Application http://fb.me/1zOf3h2K8 JDeveloper & ADF ?Fusion Apps Enterprise Repository - Explained http://dlvr.it/1rpjWd Steve Walker ?Oracle #Exalogic is the logical choice for running business applications. Exalogic Software 2.0 launches 7/25. Reg at http://bit.ly/NedQ9L A. Chatziantoniou ?Landed in rainy Amsterdam after a great week in Lisbon for the #ofmsummercamps - multo obrigado for Jürgen for another fantastic event SOA Community ?Teams present #BPM11g POC results at #ofmsummercamps - great job! #soacommunity pic.twitter.com/0d4txkWF Sabine Leitner ?#DOAG SIG Middleware 29.08.2012 Köln über MW, Administration, Monitoring http://bit.ly/P47w82 @soacommunity @OracleMW @OracleFMW 12 Jul philmulhall ?Thanks @soacommunity for a great week at the #ofmsummercamps. Hard work done so time for a few cold ones in Lisboa. pic.twitter.com/LVUUuwTh peter230769 ?RT: andrea_rocco_31: RT @soacommunity: Enjoy the networking event at #ofmsummercamps want to attend next time ... pic.twitter.com/D1HRndi4 Niels Gorter ?#ofmsummercamps dinner in Lisbon. Great weather, scenery, training, people, on and on. Big THANKS @soacommunity JDeveloper & ADF ?Running Oracle BPM 11g PS5 Worklist Task Flow and Human Task Form on Non-SOA Domain http://dlvr.it/1r0c2j Andrea Rocco ?RT @soacommunity: Jamy pastry at cafe Belem - who is the ghost there?!? http://via.me/-2x33uk6 Simon Haslam ?Sounds great - sorry I couldn't make it. RT @soacommunity: 6pm BPM advanced training hard work to build the POC #ofmsummercamps philmulhall ?A well earned rest after a hard days work @soacommunity #summercamps pic.twitter.com/LKK7VOVS philmulhall ?Some more hard working delegates @soacommunity #summercamps pic.twitter.com/gWpk1HZh SOA Community ?Error message at the BPM POC - will The #ace director understand the message and solve it? #ofmsummercamps pic.twitter.com/LFTEzNck Daniel Kleine-Albers ?posted on the #thecattlecrew blog: Assigning more memory to JDeveloper http://thecattlecrew.wordpress.com/2012/07/10/jdeveloper-quicktip-assigning-more-memory/ … OTNArchBeat ?BAM design pointers | Kavitha Srinivasan http://pub.vitrue.com/TOhP SOA Community ?Did you receive the July SOA community newsletter? read it! Want to become a member http://www.oracle.com/goto/emea/soa #soacommunity #soa #opn OracleBlogs ?Markus Zirn, Big Data with CEP and SOA @ SOA, Cloud &amp; Service Technology Symposium 2012 http://ow.ly/1lcSkb Andrejus Baranovskis Running Oracle BPM 11g PS5 Worklist Task Flow and Human Task Form on Non-SOA Eric Elzinga ?Service Facade design pattern in OSB, http://bit.ly/NnOExN Eric Elzinga ?New BPEL Thread Pool in SOA 11g for Non-Blocking Invoke Activities from 11.1.1.6 (PS5), http://bit.ly/NnOc2G Gilberto Holms New Post: Siebel Connection Pool in Oracle Service Bus 11g http://wp.me/pRE8V-2z Oracle UPK & Tutor ?UPK Pre-Built Content Update: UPK pre-built content development efforts are always underway and growing. Ove... http://bit.ly/R2HeTj JDeveloper & ADF ?Troubleshooting BPMN process editor problems in 11.1.1.6 http://dlvr.it/1p0FfS orclateamsoa ?A-Team Blog #ateam: BAM design pointers - In working recently with a large Oracle customer on SOA and BAM, I discove... http://ow.ly/1kYqES SOA Community BPMN process editor problems in 11.1.1.6 by Mark Nelson http://redstack.wordpress.com/2012/06/27/bpmn-process-editor-problems-in-11-1-1-6 … #soacommunity #bpm OTNArchBeat ?SOA Learning Library: free short, topic-focused training on Oracle SOA & BPM products | @SOACommunity http://pub.vitrue.com/NE1G Andrejus Baranovskis ?ADF 11g PS5 Application with Customized BPM Worklist Task Flow (MDS Seeded Customization) http://fb.me/1coX4r1X1 OTNArchBeat ?A Universal JMX Client for Weblogic –Part 1: Monitoring BPEL Thread Pools in SOA 11g | Stefan Koser http://pub.vitrue.com/mQVZ OTNArchBeat ?BPM – Disable DBMS job to refresh B2B Materialized View | Mark Nelson http://pub.vitrue.com/3PR0 SOA & BPM Partner Community For regular information on Oracle SOA Suite become a member in the SOA & BPM Partner Community for registration please visit  www.oracle.com/goto/emea/soa (OPN account required) If you need support with your account please contact the Oracle Partner Business Center. Blog Twitter LinkedIn Mix Forum Technorati Tags: SOA Community twitter,SOA Community,Oracle SOA,Oracle BPM,BPM Community,OPN,Jürgen Kress

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  • SQL SERVER – Concurrency Basics – Guest Post by Vinod Kumar

    - by pinaldave
    This guest post is by Vinod Kumar. Vinod Kumar has worked with SQL Server extensively since joining the industry over a decade ago. Working on various versions from SQL Server 7.0, Oracle 7.3 and other database technologies – he now works with the Microsoft Technology Center (MTC) as a Technology Architect. Let us read the blog post in Vinod’s own voice. Learning is always fun when it comes to SQL Server and learning the basics again can be more fun. I did write about Transaction Logs and recovery over my blogs and the concept of simplifying the basics is a challenge. In the real world we always see checks and queues for a process – say railway reservation, banks, customer supports etc there is a process of line and queue to facilitate everyone. Shorter the queue higher is the efficiency of system (a.k.a higher is the concurrency). Every database does implement this using checks like locking, blocking mechanisms and they implement the standards in a way to facilitate higher concurrency. In this post, let us talk about the topic of Concurrency and what are the various aspects that one needs to know about concurrency inside SQL Server. Let us learn the concepts as one-liners: Concurrency can be defined as the ability of multiple processes to access or change shared data at the same time. The greater the number of concurrent user processes that can be active without interfering with each other, the greater the concurrency of the database system. Concurrency is reduced when a process that is changing data prevents other processes from reading that data or when a process that is reading data prevents other processes from changing that data. Concurrency is also affected when multiple processes are attempting to change the same data simultaneously. Two approaches to managing concurrent data access: Optimistic Concurrency Model Pessimistic Concurrency Model Concurrency Models Pessimistic Concurrency Default behavior: acquire locks to block access to data that another process is using. Assumes that enough data modification operations are in the system that any given read operation is likely affected by a data modification made by another user (assumes conflicts will occur). Avoids conflicts by acquiring a lock on data being read so no other processes can modify that data. Also acquires locks on data being modified so no other processes can access the data for either reading or modifying. Readers block writer, writers block readers and writers. Optimistic Concurrency Assumes that there are sufficiently few conflicting data modification operations in the system that any single transaction is unlikely to modify data that another transaction is modifying. Default behavior of optimistic concurrency is to use row versioning to allow data readers to see the state of the data before the modification occurs. Older versions of the data are saved so a process reading data can see the data as it was when the process started reading and not affected by any changes being made to that data. Processes modifying the data is unaffected by processes reading the data because the reader is accessing a saved version of the data rows. Readers do not block writers and writers do not block readers, but, writers can and will block writers. Transaction Processing A transaction is the basic unit of work in SQL Server. Transaction consists of SQL commands that read and update the database but the update is not considered final until a COMMIT command is issued (at least for an explicit transaction: marked with a BEGIN TRAN and the end is marked by a COMMIT TRAN or ROLLBACK TRAN). Transactions must exhibit all the ACID properties of a transaction. ACID Properties Transaction processing must guarantee the consistency and recoverability of SQL Server databases. Ensures all transactions are performed as a single unit of work regardless of hardware or system failure. A – Atomicity C – Consistency I – Isolation D- Durability Atomicity: Each transaction is treated as all or nothing – it either commits or aborts. Consistency: ensures that a transaction won’t allow the system to arrive at an incorrect logical state – the data must always be logically correct.  Consistency is honored even in the event of a system failure. Isolation: separates concurrent transactions from the updates of other incomplete transactions. SQL Server accomplishes isolation among transactions by locking data or creating row versions. Durability: After a transaction commits, the durability property ensures that the effects of the transaction persist even if a system failure occurs. If a system failure occurs while a transaction is in progress, the transaction is completely undone, leaving no partial effects on data. Transaction Dependencies In addition to supporting all four ACID properties, a transaction might exhibit few other behaviors (known as dependency problems or consistency problems). Lost Updates: Occur when two processes read the same data and both manipulate the data, changing its value and then both try to update the original data to the new value. The second process might overwrite the first update completely. Dirty Reads: Occurs when a process reads uncommitted data. If one process has changed data but not yet committed the change, another process reading the data will read it in an inconsistent state. Non-repeatable Reads: A read is non-repeatable if a process might get different values when reading the same data in two reads within the same transaction. This can happen when another process changes the data in between the reads that the first process is doing. Phantoms: Occurs when membership in a set changes. It occurs if two SELECT operations using the same predicate in the same transaction return a different number of rows. Isolation Levels SQL Server supports 5 isolation levels that control the behavior of read operations. Read Uncommitted All behaviors except for lost updates are possible. Implemented by allowing the read operations to not take any locks, and because of this, it won’t be blocked by conflicting locks acquired by other processes. The process can read data that another process has modified but not yet committed. When using the read uncommitted isolation level and scanning an entire table, SQL Server can decide to do an allocation order scan (in page-number order) instead of a logical order scan (following page pointers). If another process doing concurrent operations changes data and move rows to a new location in the table, the allocation order scan can end up reading the same row twice. Also can happen if you have read a row before it is updated and then an update moves the row to a higher page number than your scan encounters later. Performing an allocation order scan under Read Uncommitted can cause you to miss a row completely – can happen when a row on a high page number that hasn’t been read yet is updated and moved to a lower page number that has already been read. Read Committed Two varieties of read committed isolation: optimistic and pessimistic (default). Ensures that a read never reads data that another application hasn’t committed. If another transaction is updating data and has exclusive locks on data, your transaction will have to wait for the locks to be released. Your transaction must put share locks on data that are visited, which means that data might be unavailable for others to use. A share lock doesn’t prevent others from reading but prevents them from updating. Read committed (snapshot) ensures that an operation never reads uncommitted data, but not by forcing other processes to wait. SQL Server generates a version of the changed row with its previous committed values. Data being changed is still locked but other processes can see the previous versions of the data as it was before the update operation began. Repeatable Read This is a Pessimistic isolation level. Ensures that if a transaction revisits data or a query is reissued the data doesn’t change. That is, issuing the same query twice within a transaction cannot pickup any changes to data values made by another user’s transaction because no changes can be made by other transactions. However, this does allow phantom rows to appear. Preventing non-repeatable read is a desirable safeguard but cost is that all shared locks in a transaction must be held until the completion of the transaction. Snapshot Snapshot Isolation (SI) is an optimistic isolation level. Allows for processes to read older versions of committed data if the current version is locked. Difference between snapshot and read committed has to do with how old the older versions have to be. It’s possible to have two transactions executing simultaneously that give us a result that is not possible in any serial execution. Serializable This is the strongest of the pessimistic isolation level. Adds to repeatable read isolation level by ensuring that if a query is reissued rows were not added in the interim, i.e, phantoms do not appear. Preventing phantoms is another desirable safeguard, but cost of this extra safeguard is similar to that of repeatable read – all shared locks in a transaction must be held until the transaction completes. In addition serializable isolation level requires that you lock data that has been read but also data that doesn’t exist. Ex: if a SELECT returned no rows, you want it to return no. rows when the query is reissued. This is implemented in SQL Server by a special kind of lock called the key-range lock. Key-range locks require that there be an index on the column that defines the range of values. If there is no index on the column, serializable isolation requires a table lock. Gets its name from the fact that running multiple serializable transactions at the same time is equivalent of running them one at a time. Now that we understand the basics of what concurrency is, the subsequent blog posts will try to bring out the basics around locking, blocking, deadlocks because they are the fundamental blocks that make concurrency possible. Now if you are with me – let us continue learning for SQL Server Locking Basics. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Performance, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology Tagged: Concurrency

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  • Understanding what SPARQL is

    - by user73119
    This is a terribly beginner series of questions, but after reading through a good 30 SPARQL tutorials I can't seem to wrap my head around what SPARQL is or how to begin using it. Is it executed on the client side? Is microsoft somehow going to be able to mess this up? Can you use a common relational database (SQL)? Are there particular resources you recommend over others for learning? Do you feel it is premature to begin investing myself in this? Best way to get set up and running to start tinkering? The RDFA examples I have seen are very inspiring. I am currently a big proponent of using microformats but would really like to take it further. I currently develop in PHP, but have only found a Java library.

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  • Listing common SQL Code Smells.

    - by Phil Factor
    Once you’ve done a number of SQL Code-reviews, you’ll know those signs in the code that all might not be well. These ’Code Smells’ are coding styles that don’t directly cause a bug, but are indicators that all is not well with the code. . Kent Beck and Massimo Arnoldi seem to have coined the phrase in the "OnceAndOnlyOnce" page of www.C2.com, where Kent also said that code "wants to be simple". Bad Smells in Code was an essay by Kent Beck and Martin Fowler, published as Chapter 3 of the book ‘Refactoring: Improving the Design of Existing Code’ (ISBN 978-0201485677) Although there are generic code-smells, SQL has its own particular coding habits that will alert the programmer to the need to re-factor what has been written. See Exploring Smelly Code   and Code Deodorants for Code Smells by Nick Harrison for a grounding in Code Smells in C# I’ve always been tempted by the idea of automating a preliminary code-review for SQL. It would be so useful to trawl through code and pick up the various problems, much like the classic ‘Lint’ did for C, and how the Code Metrics plug-in for .NET Reflector by Jonathan 'Peli' de Halleux is used for finding Code Smells in .NET code. The problem is that few of the standard procedural code smells are relevant to SQL, and we need an agreed list of code smells. Merrilll Aldrich made a grand start last year in his blog Top 10 T-SQL Code Smells.However, I'd like to make a start by discovering if there is a general opinion amongst Database developers what the most important SQL Smells are. One can be a bit defensive about code smells. I will cheerfully write very long stored procedures, even though they are frowned on. I’ll use dynamic SQL occasionally. You can only use them as an aid for your own judgment and it is fine to ‘sign them off’ as being appropriate in particular circumstances. Also, whole classes of ‘code smells’ may be irrelevant for a particular database. The use of proprietary SQL, for example, is only a ‘code smell’ if there is a chance that the database will have to be ported to another RDBMS. The use of dynamic SQL is a risk only with certain security models. As the saying goes,  a CodeSmell is a hint of possible bad practice to a pragmatist, but a sure sign of bad practice to a purist. Plamen Ratchev’s wonderful article Ten Common SQL Programming Mistakes lists some of these ‘code smells’ along with out-and-out mistakes, but there are more. The use of nested transactions, for example, isn’t entirely incorrect, even though the database engine ignores all but the outermost: but it does flag up the possibility that the programmer thinks that nested transactions are supported. If anything requires some sort of general agreement, the definition of code smells is one. I’m therefore going to make this Blog ‘dynamic, in that, if anyone twitters a suggestion with a #SQLCodeSmells tag (or sends me a twitter) I’ll update the list here. If you add a comment to the blog with a suggestion of what should be added or removed, I’ll do my best to oblige. In other words, I’ll try to keep this blog up to date. The name against each 'smell' is the name of the person who Twittered me, commented about or who has written about the 'smell'. it does not imply that they were the first ever to think of the smell! Use of deprecated syntax such as *= (Dave Howard) Denormalisation that requires the shredding of the contents of columns. (Merrill Aldrich) Contrived interfaces Use of deprecated datatypes such as TEXT/NTEXT (Dave Howard) Datatype mis-matches in predicates that rely on implicit conversion.(Plamen Ratchev) Using Correlated subqueries instead of a join   (Dave_Levy/ Plamen Ratchev) The use of Hints in queries, especially NOLOCK (Dave Howard /Mike Reigler) Few or No comments. Use of functions in a WHERE clause. (Anil Das) Overuse of scalar UDFs (Dave Howard, Plamen Ratchev) Excessive ‘overloading’ of routines. The use of Exec xp_cmdShell (Merrill Aldrich) Excessive use of brackets. (Dave Levy) Lack of the use of a semicolon to terminate statements Use of non-SARGable functions on indexed columns in predicates (Plamen Ratchev) Duplicated code, or strikingly similar code. Misuse of SELECT * (Plamen Ratchev) Overuse of Cursors (Everyone. Special mention to Dave Levy & Adrian Hills) Overuse of CLR routines when not necessary (Sam Stange) Same column name in different tables with different datatypes. (Ian Stirk) Use of ‘broken’ functions such as ‘ISNUMERIC’ without additional checks. Excessive use of the WHILE loop (Merrill Aldrich) INSERT ... EXEC (Merrill Aldrich) The use of stored procedures where a view is sufficient (Merrill Aldrich) Not using two-part object names (Merrill Aldrich) Using INSERT INTO without specifying the columns and their order (Merrill Aldrich) Full outer joins even when they are not needed. (Plamen Ratchev) Huge stored procedures (hundreds/thousands of lines). Stored procedures that can produce different columns, or order of columns in their results, depending on the inputs. Code that is never used. Complex and nested conditionals WHILE (not done) loops without an error exit. Variable name same as the Datatype Vague identifiers. Storing complex data  or list in a character map, bitmap or XML field User procedures with sp_ prefix (Aaron Bertrand)Views that reference views that reference views that reference views (Aaron Bertrand) Inappropriate use of sql_variant (Neil Hambly) Errors with identity scope using SCOPE_IDENTITY @@IDENTITY or IDENT_CURRENT (Neil Hambly, Aaron Bertrand) Schemas that involve multiple dated copies of the same table instead of partitions (Matt Whitfield-Atlantis UK) Scalar UDFs that do data lookups (poor man's join) (Matt Whitfield-Atlantis UK) Code that allows SQL Injection (Mladen Prajdic) Tables without clustered indexes (Matt Whitfield-Atlantis UK) Use of "SELECT DISTINCT" to mask a join problem (Nick Harrison) Multiple stored procedures with nearly identical implementation. (Nick Harrison) Excessive column aliasing may point to a problem or it could be a mapping implementation. (Nick Harrison) Joining "too many" tables in a query. (Nick Harrison) Stored procedure returning more than one record set. (Nick Harrison) A NOT LIKE condition (Nick Harrison) excessive "OR" conditions. (Nick Harrison) User procedures with sp_ prefix (Aaron Bertrand) Views that reference views that reference views that reference views (Aaron Bertrand) sp_OACreate or anything related to it (Bill Fellows) Prefixing names with tbl_, vw_, fn_, and usp_ ('tibbling') (Jeremiah Peschka) Aliases that go a,b,c,d,e... (Dave Levy/Diane McNurlan) Overweight Queries (e.g. 4 inner joins, 8 left joins, 4 derived tables, 10 subqueries, 8 clustered GUIDs, 2 UDFs, 6 case statements = 1 query) (Robert L Davis) Order by 3,2 (Dave Levy) MultiStatement Table functions which are then filtered 'Sel * from Udf() where Udf.Col = Something' (Dave Ballantyne) running a SQL 2008 system in SQL 2000 compatibility mode(John Stafford)

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  • SQL SERVER – Extending SQL Azure with Azure worker role – Guest Post by Paras Doshi

    - by pinaldave
    This is guest post by Paras Doshi. Paras Doshi is a research Intern at SolidQ.com and a Microsoft student partner. He is currently working in the domain of SQL Azure. SQL Azure is nothing but a SQL server in the cloud. SQL Azure provides benefits such as on demand rapid provisioning, cost-effective scalability, high availability and reduced management overhead. To see an introduction on SQL Azure, check out the post by Pinal here In this article, we are going to discuss how to extend SQL Azure with the Azure worker role. In other words, we will attempt to write a custom code and host it in the Azure worker role; the aim is to add some features that are not available with SQL Azure currently or features that need to be customized for flexibility. This way we extend the SQL Azure capability by building some solutions that run on Azure as worker roles. To understand Azure worker role, think of it as a windows service in cloud. Azure worker role can perform background processes, and to handle processes such as synchronization and backup, it becomes our ideal tool. First, we will focus on writing a worker role code that synchronizes SQL Azure databases. Before we do so, let’s see some scenarios in which synchronization between SQL Azure databases is beneficial: scaling out access over multiple databases enables us to handle workload efficiently As of now, SQL Azure database can be hosted in one of any six datacenters. By synchronizing databases located in different data centers, one can extend the data by enabling access to geographically distributed data Let us see some scenarios in which SQL server to SQL Azure database synchronization is beneficial To backup SQL Azure database on local infrastructure Rather than investing in local infrastructure for increased workloads, such workloads could be handled by cloud Ability to extend data to different datacenters located across the world to enable efficient data access from remote locations Now, let us develop cloud-based app that synchronizes SQL Azure databases. For an Introduction to developing cloud based apps, click here Now, in this article, I aim to provide a bird’s eye view of how a code that synchronizes SQL Azure databases look like and then list resources that can help you develop the solution from scratch. Now, if you newly add a worker role to the cloud-based project, this is how the code will look like. (Note: I have added comments to the skeleton code to point out the modifications that will be required in the code to carry out the SQL Azure synchronization. Note the placement of Setup() and Sync() function.) Click here (http://parasdoshi1989.files.wordpress.com/2011/06/code-snippet-1-for-extending-sql-azure-with-azure-worker-role1.pdf ) Enabling SQL Azure databases synchronization through sync framework is a two-step process. In the first step, the database is provisioned and sync framework creates tracking tables, stored procedures, triggers, and tables to store metadata to enable synchronization. This is one time step. The code for the same is put in the setup() function which is called once when the worker role starts. Now, the second step is continuous (or on demand) synchronization of SQL Azure databases by propagating changes between databases. This is done on a continuous basis by calling the sync() function in the while loop. The code logic to synchronize changes between SQL Azure databases should be put in the sync() function. Discussing the coding part step by step is out of the scope of this article. Therefore, let me suggest you a resource, which is given here. Also, note that before you start developing the code, you will need to install SYNC framework 2.1 SDK (download here). Further, you will reference some libraries before you start coding. Details regarding the same are available in the article that I just pointed to. You will be charged for data transfers if the databases are not in the same datacenter. For pricing information, go here Currently, a tool named DATA SYNC, which is built on top of sync framework, is available in CTP that allows SQL Azure <-> SQL server and SQL Azure <-> SQL Azure synchronization (without writing single line of code); however, in some cases, the custom code shown in this blogpost provides flexibility that is not available with Data SYNC. For instance, filtering is not supported in the SQL Azure DATA SYNC CTP2; if you wish to have such a functionality now, then you have the option of developing a custom code using SYNC Framework. Now, this code can be easily extended to synchronize at some schedule. Let us say we want the databases to get synchronized every day at 10:00 pm. This is what the code will look like now: (http://parasdoshi1989.files.wordpress.com/2011/06/code-snippet-2-for-extending-sql-azure-with-azure-worker-role.pdf) Don’t you think that by writing such a code, we are imitating the functionality provided by the SQL server agent for a SQL server? Think about it. We are scheduling our administrative task by writing custom code – in other words, we have developed a “Light weight SQL server agent for SQL Azure!” Since the SQL server agent is not currently available in cloud, we have developed a solution that enables us to schedule tasks, and thus we have extended SQL Azure with the Azure worker role! Now if you wish to track jobs, you can do so by storing this data in SQL Azure (or Azure tables). The reason is that Windows Azure is a stateless platform, and we will need to store the state of the job ourselves and the choice that you have is SQL Azure or Azure tables. Note that this solution requires custom code and also it is not UI driven; however, for now, it can act as a temporary solution until SQL server agent is made available in the cloud. Moreover, this solution does not encompass functionalities that a SQL server agent provides, but it does open up an interesting avenue to schedule some of the tasks such as backup and synchronization of SQL Azure databases by writing some custom code in the Azure worker role. Now, let us see one more possibility – i.e., running BCP through a worker role in Azure-hosted services and then uploading the backup files either locally or on blobs. If you upload it locally, then consider the data transfer cost. If you upload it to blobs residing in the same datacenter, then no transfer cost applies but the cost on blob size applies. So, before choosing the option, you need to evaluate your preferences keeping the cost associated with each option in mind. In this article, I have shown that Azure worker role solution could be developed to synchronize SQL Azure databases. Moreover, a light-weight SQL server agent for SQL Azure can be developed. Also we discussed the possibility of running BCP through a worker role in Azure-hosted services for backing up our precious SQL Azure data. Thus, we can extend SQL Azure with the Azure worker role. But remember: you will be charged for running Azure worker roles. So at the end of the day, you need to ask – am I willing to build a custom code and pay money to achieve this functionality? I hope you found this blog post interesting. If you have any questions/feedback, you can comment below or you can mail me at Paras[at]student-partners[dot]com Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: Pinal Dave, PostADay, SQL, SQL Authority, SQL Azure, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

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  • SQL Monitor’s data repository

    - by Chris Lambrou
    As one of the developers of SQL Monitor, I often get requests passed on by our support people from customers who are looking to dip into SQL Monitor’s own data repository, in order to pull out bits of information that they’re interested in. Since there’s clearly interest out there in playing around directly with the data repository, I thought I’d write some blog posts to start to describe how it all works. The hardest part for me is knowing where to begin, since the schema of the data repository is pretty big. Hmmm… I guess it’s tricky for anyone to write anything but the most trivial of queries against the data repository without understanding the hierarchy of monitored objects, so perhaps my first post should start there. I always imagine that whenever a customer fires up SSMS and starts to explore their SQL Monitor data repository database, they become immediately bewildered by the schema – that was certainly my experience when I did so for the first time. The following query shows the number of different object types in the data repository schema: SELECT type_desc, COUNT(*) AS [count] FROM sys.objects GROUP BY type_desc ORDER BY type_desc;  type_desccount 1DEFAULT_CONSTRAINT63 2FOREIGN_KEY_CONSTRAINT181 3INTERNAL_TABLE3 4PRIMARY_KEY_CONSTRAINT190 5SERVICE_QUEUE3 6SQL_INLINE_TABLE_VALUED_FUNCTION381 7SQL_SCALAR_FUNCTION2 8SQL_STORED_PROCEDURE100 9SYSTEM_TABLE41 10UNIQUE_CONSTRAINT54 11USER_TABLE193 12VIEW124 With 193 tables, 124 views, 100 stored procedures and 381 table valued functions, that’s quite a hefty schema, and when you browse through it using SSMS, it can be a bit daunting at first. So, where to begin? Well, let’s narrow things down a bit and only look at the tables belonging to the data schema. That’s where all of the collected monitoring data is stored by SQL Monitor. The following query gives us the names of those tables: SELECT sch.name + '.' + obj.name AS [name] FROM sys.objects obj JOIN sys.schemas sch ON sch.schema_id = obj.schema_id WHERE obj.type_desc = 'USER_TABLE' AND sch.name = 'data' ORDER BY sch.name, obj.name; This query still returns 110 tables. I won’t show them all here, but let’s have a look at the first few of them:  name 1data.Cluster_Keys 2data.Cluster_Machine_ClockSkew_UnstableSamples 3data.Cluster_Machine_Cluster_StableSamples 4data.Cluster_Machine_Keys 5data.Cluster_Machine_LogicalDisk_Capacity_StableSamples 6data.Cluster_Machine_LogicalDisk_Keys 7data.Cluster_Machine_LogicalDisk_Sightings 8data.Cluster_Machine_LogicalDisk_UnstableSamples 9data.Cluster_Machine_LogicalDisk_Volume_StableSamples 10data.Cluster_Machine_Memory_Capacity_StableSamples 11data.Cluster_Machine_Memory_UnstableSamples 12data.Cluster_Machine_Network_Capacity_StableSamples 13data.Cluster_Machine_Network_Keys 14data.Cluster_Machine_Network_Sightings 15data.Cluster_Machine_Network_UnstableSamples 16data.Cluster_Machine_OperatingSystem_StableSamples 17data.Cluster_Machine_Ping_UnstableSamples 18data.Cluster_Machine_Process_Instances 19data.Cluster_Machine_Process_Keys 20data.Cluster_Machine_Process_Owner_Instances 21data.Cluster_Machine_Process_Sightings 22data.Cluster_Machine_Process_UnstableSamples 23… There are two things I want to draw your attention to: The table names describe a hierarchy of the different types of object that are monitored by SQL Monitor (e.g. clusters, machines and disks). For each object type in the hierarchy, there are multiple tables, ending in the suffixes _Keys, _Sightings, _StableSamples and _UnstableSamples. Not every object type has a table for every suffix, but the _Keys suffix is especially important and a _Keys table does indeed exist for every object type. In fact, if we limit the query to return only those tables ending in _Keys, we reveal the full object hierarchy: SELECT sch.name + '.' + obj.name AS [name] FROM sys.objects obj JOIN sys.schemas sch ON sch.schema_id = obj.schema_id WHERE obj.type_desc = 'USER_TABLE' AND sch.name = 'data' AND obj.name LIKE '%_Keys' ORDER BY sch.name, obj.name;  name 1data.Cluster_Keys 2data.Cluster_Machine_Keys 3data.Cluster_Machine_LogicalDisk_Keys 4data.Cluster_Machine_Network_Keys 5data.Cluster_Machine_Process_Keys 6data.Cluster_Machine_Services_Keys 7data.Cluster_ResourceGroup_Keys 8data.Cluster_ResourceGroup_Resource_Keys 9data.Cluster_SqlServer_Agent_Job_History_Keys 10data.Cluster_SqlServer_Agent_Job_Keys 11data.Cluster_SqlServer_Database_BackupType_Backup_Keys 12data.Cluster_SqlServer_Database_BackupType_Keys 13data.Cluster_SqlServer_Database_CustomMetric_Keys 14data.Cluster_SqlServer_Database_File_Keys 15data.Cluster_SqlServer_Database_Keys 16data.Cluster_SqlServer_Database_Table_Index_Keys 17data.Cluster_SqlServer_Database_Table_Keys 18data.Cluster_SqlServer_Error_Keys 19data.Cluster_SqlServer_Keys 20data.Cluster_SqlServer_Services_Keys 21data.Cluster_SqlServer_SqlProcess_Keys 22data.Cluster_SqlServer_TopQueries_Keys 23data.Cluster_SqlServer_Trace_Keys 24data.Group_Keys The full object type hierarchy looks like this: Cluster Machine LogicalDisk Network Process Services ResourceGroup Resource SqlServer Agent Job History Database BackupType Backup CustomMetric File Table Index Error Services SqlProcess TopQueries Trace Group Okay, but what about the individual objects themselves represented at each level in this hierarchy? Well that’s what the _Keys tables are for. This is probably best illustrated by way of a simple example – how can I query my own data repository to find the databases on my own PC for which monitoring data has been collected? Like this: SELECT clstr._Name AS cluster_name, srvr._Name AS instance_name, db._Name AS database_name FROM data.Cluster_SqlServer_Database_Keys db JOIN data.Cluster_SqlServer_Keys srvr ON db.ParentId = srvr.Id -- Note here how the parent of a Database is a Server JOIN data.Cluster_Keys clstr ON srvr.ParentId = clstr.Id -- Note here how the parent of a Server is a Cluster WHERE clstr._Name = 'dev-chrisl2' -- This is the hostname of my own PC ORDER BY clstr._Name, srvr._Name, db._Name;  cluster_nameinstance_namedatabase_name 1dev-chrisl2SqlMonitorData 2dev-chrisl2master 3dev-chrisl2model 4dev-chrisl2msdb 5dev-chrisl2mssqlsystemresource 6dev-chrisl2tempdb 7dev-chrisl2sql2005SqlMonitorData 8dev-chrisl2sql2005TestDatabase 9dev-chrisl2sql2005master 10dev-chrisl2sql2005model 11dev-chrisl2sql2005msdb 12dev-chrisl2sql2005mssqlsystemresource 13dev-chrisl2sql2005tempdb 14dev-chrisl2sql2008SqlMonitorData 15dev-chrisl2sql2008master 16dev-chrisl2sql2008model 17dev-chrisl2sql2008msdb 18dev-chrisl2sql2008mssqlsystemresource 19dev-chrisl2sql2008tempdb These results show that I have three SQL Server instances on my machine (a default instance, one named sql2005 and one named sql2008), and each instance has the usual set of system databases, along with a database named SqlMonitorData. Basically, this is where I test SQL Monitor on different versions of SQL Server, when I’m developing. There are a few important things we can learn from this query: Each _Keys table has a column named Id. This is the primary key. Each _Keys table has a column named ParentId. A foreign key relationship is defined between each _Keys table and its parent _Keys table in the hierarchy. There are two exceptions to this, Cluster_Keys and Group_Keys, because clusters and groups live at the root level of the object hierarchy. Each _Keys table has a column named _Name. This is used to uniquely identify objects in the table within the scope of the same shared parent object. Actually, that last item isn’t always true. In some cases, the _Name column is actually called something else. For example, the data.Cluster_Machine_Services_Keys table has a column named _ServiceName instead of _Name (sorry for the inconsistency). In other cases, a name isn’t sufficient to uniquely identify an object. For example, right now my PC has multiple processes running, all sharing the same name, Chrome (one for each tab open in my web-browser). In such cases, multiple columns are used to uniquely identify an object within the scope of the same shared parent object. Well, that’s it for now. I’ve given you enough information for you to explore the _Keys tables to see how objects are stored in your own data repositories. In a future post, I’ll try to explain how monitoring data is stored for each object, using the _StableSamples and _UnstableSamples tables. If you have any questions about this post, or suggestions for future posts, just submit them in the comments section below.

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  • Inside the Concurrent Collections: ConcurrentBag

    - by Simon Cooper
    Unlike the other concurrent collections, ConcurrentBag does not really have a non-concurrent analogy. As stated in the MSDN documentation, ConcurrentBag is optimised for the situation where the same thread is both producing and consuming items from the collection. We'll see how this is the case as we take a closer look. Again, I recommend you have ConcurrentBag open in a decompiler for reference. Thread Statics ConcurrentBag makes heavy use of thread statics - static variables marked with ThreadStaticAttribute. This is a special attribute that instructs the CLR to scope any values assigned to or read from the variable to the executing thread, not globally within the AppDomain. This means that if two different threads assign two different values to the same thread static variable, one value will not overwrite the other, and each thread will see the value they assigned to the variable, separately to any other thread. This is a very useful function that allows for ConcurrentBag's concurrency properties. You can think of a thread static variable: [ThreadStatic] private static int m_Value; as doing the same as: private static Dictionary<Thread, int> m_Values; where the executing thread's identity is used to automatically set and retrieve the corresponding value in the dictionary. In .NET 4, this usage of ThreadStaticAttribute is encapsulated in the ThreadLocal class. Lists of lists ConcurrentBag, at its core, operates as a linked list of linked lists: Each outer list node is an instance of ThreadLocalList, and each inner list node is an instance of Node. Each outer ThreadLocalList is owned by a particular thread, accessible through the thread local m_locals variable: private ThreadLocal<ThreadLocalList<T>> m_locals It is important to note that, although the m_locals variable is thread-local, that only applies to accesses through that variable. The objects referenced by the thread (each instance of the ThreadLocalList object) are normal heap objects that are not specific to any thread. Thinking back to the Dictionary analogy above, if each value stored in the dictionary could be accessed by other means, then any thread could access the value belonging to other threads using that mechanism. Only reads and writes to the variable defined as thread-local are re-routed by the CLR according to the executing thread's identity. So, although m_locals is defined as thread-local, the m_headList, m_nextList and m_tailList variables aren't. This means that any thread can access all the thread local lists in the collection by doing a linear search through the outer linked list defined by these variables. Adding items So, onto the collection operations. First, adding items. This one's pretty simple. If the current thread doesn't already own an instance of ThreadLocalList, then one is created (or, if there are lists owned by threads that have stopped, it takes control of one of those). Then the item is added to the head of that thread's list. That's it. Don't worry, it'll get more complicated when we account for the other operations on the list! Taking & Peeking items This is where it gets tricky. If the current thread's list has items in it, then it peeks or removes the head item (not the tail item) from the local list and returns that. However, if the local list is empty, it has to go and steal another item from another list, belonging to a different thread. It iterates through all the thread local lists in the collection using the m_headList and m_nextList variables until it finds one that has items in it, and it steals one item from that list. Up to this point, the two threads had been operating completely independently. To steal an item from another thread's list, the stealing thread has to do it in such a way as to not step on the owning thread's toes. Recall how adding and removing items both operate on the head of the thread's linked list? That gives us an easy way out - a thread trying to steal items from another thread can pop in round the back of another thread's list using the m_tail variable, and steal an item from the back without the owning thread knowing anything about it. The owning thread can carry on completely independently, unaware that one of its items has been nicked. However, this only works when there are at least 3 items in the list, as that guarantees there will be at least one node between the owning thread performing operations on the list head and the thread stealing items from the tail - there's no chance of the two threads operating on the same node at the same time and causing a race condition. If there's less than three items in the list, then there does need to be some synchronization between the two threads. In this case, the lock on the ThreadLocalList object is used to mediate access to a thread's list when there's the possibility of contention. Thread synchronization In ConcurrentBag, this is done using several mechanisms: Operations performed by the owner thread only take out the lock when there are less than three items in the collection. With three or greater items, there won't be any conflict with a stealing thread operating on the tail of the list. If a lock isn't taken out, the owning thread sets the list's m_currentOp variable to a non-zero value for the duration of the operation. This indicates to all other threads that there is a non-locked operation currently occuring on that list. The stealing thread always takes out the lock, to prevent two threads trying to steal from the same list at the same time. After taking out the lock, the stealing thread spinwaits until m_currentOp has been set to zero before actually performing the steal. This ensures there won't be a conflict with the owning thread when the number of items in the list is on the 2-3 item borderline. If any add or remove operations are started in the meantime, and the list is below 3 items, those operations try to take out the list's lock and are blocked until the stealing thread has finished. This allows a thread to steal an item from another thread's list without corrupting it. What about synchronization in the collection as a whole? Collection synchronization Any thread that operates on the collection's global structure (accessing anything outside the thread local lists) has to take out the collection's global lock - m_globalListsLock. This single lock is sufficient when adding a new thread local list, as the items inside each thread's list are unaffected. However, what about operations (such as Count or ToArray) that need to access every item in the collection? In order to ensure a consistent view, all operations on the collection are stopped while the count or ToArray is performed. This is done by freezing the bag at the start, performing the global operation, and unfreezing at the end: The global lock is taken out, to prevent structural alterations to the collection. m_needSync is set to true. This notifies all the threads that they need to take out their list's lock irregardless of what operation they're doing. All the list locks are taken out in order. This blocks all locking operations on the lists. The freezing thread waits for all current lockless operations to finish by spinwaiting on each m_currentOp field. The global operation can then be performed while the bag is frozen, but no other operations can take place at the same time, as all other threads are blocked on a list's lock. Then, once the global operation has finished, the locks are released, m_needSync is unset, and normal concurrent operation resumes. Concurrent principles That's the essence of how ConcurrentBag operates. Each thread operates independently on its own local list, except when they have to steal items from another list. When stealing, only the stealing thread is forced to take out the lock; the owning thread only has to when there is the possibility of contention. And a global lock controls accesses to the structure of the collection outside the thread lists. Operations affecting the entire collection take out all locks in the collection to freeze the contents at a single point in time. So, what principles can we extract here? Threads operate independently Thread-static variables and ThreadLocal makes this easy. Threads operate entirely concurrently on their own structures; only when they need to grab data from another thread is there any thread contention. Minimised lock-taking Even when two threads need to operate on the same data structures (one thread stealing from another), they do so in such a way such that the probability of actually blocking on a lock is minimised; the owning thread always operates on the head of the list, and the stealing thread always operates on the tail. Management of lockless operations Any operations that don't take out a lock still have a 'hook' to force them to lock when necessary. This allows all operations on the collection to be stopped temporarily while a global snapshot is taken. Hopefully, such operations will be short-lived and infrequent. That's all the concurrent collections covered. I hope you've found it as informative and interesting as I have. Next, I'll be taking a closer look at ThreadLocal, which I came across while analyzing ConcurrentBag. As you'll see, the operation of this class deserves a much closer look.

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  • Creating a user-defined code generation system in PHP

    - by user270766
    My newest project that I'm looking to build with CodeIgniter would require some sort of system that would allow a user to drag and drop pre-defined functions/methods into mini-classes/objects and then run/test them in the browser. So it'd something similar to Scratch. I've designed a relational database that I think could work for this (storing the function names and have these classes "subscribe" to those functions) - but I'm wondering whether or not to go ahead with it. Is there a better way to do this or is there a system out there that would accomplish this for me? EDIT: It would have to be extremely simple for an end user, but hopefully be flexible enough to easily add more complex functionality in the future.

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  • Amazon Web Services (AWS) Plug-in for Oracle Enterprise Manager

    - by Anand Akela
    v\:* {behavior:url(#default#VML);} o\:* {behavior:url(#default#VML);} w\:* {behavior:url(#default#VML);} .shape {behavior:url(#default#VML);} Normal 0 false false false false EN-US X-NONE X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:"Calibri","sans-serif"; mso-bidi-font-family:"Times New Roman";} Contributed by Sunil Kunisetty and Daniel Chan Introduction and ArchitectureAs more and more enterprises deploy some of their non-critical workload on Amazon Web Services (AWS), it’s becoming critical to monitor those public AWS resources along side with their on-premise resources. Oracle recently announced Oracle Enterprise Manager Plug-in for Amazon Web Services (AWS) allows you to achieve that goal. The on-premise Oracle Enterprise Manager (EM12c) acts as a single tool to get a comprehensive view of your public AWS resources as well as your private cloud resources.  By deploying the plug-in within your Cloud Control environment, you gain the following management features: Monitor EBS, EC2 and RDS instances on Amazon Web Services Gather performance metrics and configuration details for AWS instances Raise alerts and violations based on thresholds set on monitoring Generate reports based on the gathered data Users of this Plug-in can leverage the rich Enterprise Manager features such as system promotion, incident generation based on thresholds, integration with 3rd party ticketing applications etc. AWS Monitoring via this Plug-in is enabled via Amazon CloudWatch API and the users of this Plug-in are responsible for supplying credentials for accessing AWS and the CloudWatch API. This Plug-in can only be deployed on an EM12C R2 platform and agent version should be at minimum 12c R2.Here is a pictorial view of the overall architecture: Amazon Elastic Block Store (EBS) Amazon Elastic Compute Cloud (EC2) Amazon Relational Database Service (RDS) Here are a few key features: Rich and exhaustive list of metrics. Metrics can be gathered from an Agent running outside AWS. Critical configuration information. Custom Home Pages with charts and AWS configuration information. Generate incidents based on thresholds set on monitoring data. Discovery and Monitoring AWS instances can be added to EM12C either via the EM12c User Interface (UI) or the EM12c Command Line Interface ( EMCLI)  by providing the AWS credentials (Secret Key and Access Key Id) as well as resource specific properties as target properties. Here is a quick mapping of target types and properties for each AWS resources AWS Resource Type Target Type Resource specific properties EBS Resource Amazon EBS Service CloudWatch base URI, EC2 Base URI, Period, Volume Id, Proxy Server and Port EC2 Resource Amazon EC2 Service CloudWatch base URI, EC2 Base URI, Period, Instance  Id, Proxy Server and Port RDS Resource Amazon RDS Service CloudWatch base URI, RDS Base URI, Period, Instance  Id, Proxy Server and Port Proxy server and port are optional and are only needed if the agent is within the firewall. Here is an emcli example to add an EC2 target. Please read the Installation and Readme guide for more details and step-by-step instructions to deploy  the plugin and adding the AWS the instances. ./emcli add_target \       -name="<target name>" \       -type="AmazonEC2Service" \       -host="<host>" \       -properties="ProxyHost=<proxy server>;ProxyPort=<proxy port>;EC2_BaseURI=http://ec2.<region>.amazonaws.com;BaseURI=http://monitoring.<region>.amazonaws.com;InstanceId=<EC2 instance Id>;Period=<data point periond>"  \     -subseparator=properties="=" ./emcli set_monitoring_credential \                 -set_name="AWSKeyCredentialSet"  \                 -target_name="<target name>"  \                 -target_type="AmazonEC2Service" \                 -cred_type="AWSKeyCredential"  \                 -attributes="AccessKeyId:<access key id>;SecretKey:<secret key>" Emcli utility is found under the ORACLE_HOME of EM12C install. Once the instance is discovered, the target will show up under the ‘All Targets’ list under “Amazon EC2 Service’. Once the instances are added, one can navigate to the custom homepages for these resource types. The custom home pages not only include critical metrics, but also vital configuration parameters and incidents raised for these instances.  By mapping the configuration parameters as instance properties, we can slice-and-dice and group various AWS instance by leveraging the EM12C Config search feature. The following configuration properties and metrics are collected for these Resource types. Resource Type Configuration Properties Metrics EBS Resource Volume Id, Volume Type, Device Name, Size, Availability Zone Response: Status Utilization: QueueLength, IdleTime Volume Statistics: ReadBrandwith, WriteBandwidth, ReadThroughput, WriteThroughput Operation Statistics: ReadSize, WriteSize, ReadLatency, WriteLatency EC2 Resource Instance ID, Owner Id, Root Device type, Instance Type. Availability Zone Response: Status CPU Utilization: CPU Utilization Disk I/O:  DiskReadBytes, DiskWriteBytes, DiskReadOps, DiskWriteOps, DiskReadRate, DiskWriteRate, DiskIOThroughput, DiskReadOpsRate, DiskWriteOpsRate, DiskOperationThroughput Network I/O : NetworkIn, NetworkOut, NetworkInRate, NetworkOutRate, NetworkThroughput RDS Resource Instance ID, Database Engine Name, Database Engine Version, Database Instance Class, Allocated Storage Size, Availability Zone Response: Status Disk I/O:  ReadIOPS, WriteIOPS, ReadLatency, WriteLatency, ReadThroughput, WriteThroughput DB Utilization:  BinLogDiskUsage, CPUUtilization, DatabaseConnections, FreeableMemory, ReplicaLag, SwapUsage Custom Home Pages As mentioned above, we have custom home pages for these target types that include basic configuration information,  last 24 hours availability, top metrics and the incidents generated. Here are few snapshots. EBS Instance Home Page: EC2 Instance Home Page: RDS Instance Home Page: Further Reading: 1)      AWS Plugin download 2)      Installation and  Read Me. 3)      Screenwatch on SlideShare 4)      Extensibility Programmer's Guide 5)      Amazon Web Services

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  • Thank You for a Great Welcome for Oracle GoldenGate 11g Release 2

    - by Irem Radzik
    Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:Calibri; mso-fareast-theme-font:minor-latin; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;} Yesterday morning we had two launch webcasts for Oracle GoldenGate 11g Release 2. I had the pleasure to present, as well as moderate the Q&A panels in both of these webcasts. Both events had hundreds of live attendees, sending us over 150 questions. Even though we left 30 minutes for Q&A, it was not nearly enough time to address for all the insightful questions our audience sent. Our product management team and I really appreciate the interaction we had yesterday and we are starting to respond back with outstanding questions today. Oracle GoldenGate’s new release launch also had great welcome from the media. You can find the links for various articles on the new release below: ITBusinessEdge Oracle Embraces Cross-Platform Data Integration Information Week: Oracle Real-Time Advance Taps Compressed Data Integration Developer News, Oracle GoldenGate Adds Deeper Oracle Integration, Extends Real-Time Performance CIO, Oracle GoldenGate Buddies Up with Sibling Software DBTA, Real-Time Data Integration: Oracle GoldenGate 11g Release 2 Now Available CBR Oracle unveils GoldenGate 11g Release 2 real-time data integration application In this blog, I want to address some of the frequently asked questions that came up during the webcasts. You can find the top questions and their answers along with related resources below. We will continue to address frequently asked questions via future blogs. Q: Will the new Integrated Capture for Oracle Database replace the Classic Capture? If not, which one do I use when? A: No, Classic Capture will be around for long time. Core platform specific features, bug fixes, and patches will be available for both Capture processes.Oracle Database specific features will be only available in the Integrated Capture. The Integrated Capture for Oracle Database is an option for users that need to capture data from compressed tables or need support for XML data types, XA on RAC. Users who don’t leverage these features should continue to use our Classic Capture. For more information on Oracle GoldenGate 11g Release 2 I recommend to check out the White paper: Oracle GoldenGate 11gR2 New Features as well as other technical white papers we have on OTN.                                                         For those of you coming to OpenWorld, please attend the related session: Extracting Data in Oracle GoldenGate Integrated Capture Mode, Monday Oct 1st 1:45pm Moscone South – 102 to learn more about this new feature. Q: What is new in Conflict Detection and Resolution? And how does it work? A: There are now pre-built functions to identify the conditions under which an error occurs and how to handle the record when the condition occurs. Error conditions handled include inserts into a target table where the row already exists, updates or deletes to target table rows that exist, but the original source data (before columns) do not match the existing data in the target row, and updates or deletes where the row does not exist in the target database table.Foreach of these conditions a method to handle the error is specified.  Please check out our recent blog on this topic and the White paper: Oracle GoldenGate 11gR2 New Features white paper.  Also, for those attending OpenWorld please attend the session: Best Practices for Conflict Detection and Resolution in Oracle GoldenGate for Active/Active-  Wednesday Oct 3rd  3:30pm Mascone 3000 Q: Does Oracle GoldenGate Veridata and the Management Pack require additional licenses, or is it incorporated with the GoldenGate license? A: Oracle GoldenGate Veridata and Oracle Management Pack for Oracle GoldenGate are additional products and require separate licenses. Please check out Oracle's price list here. Q: Does GoldenGate - Oracle Enterprise Manager Plug-in require additional license? A: Oracle Enterprise Manager Plug-in is included in the Oracle Management Pack for Oracle GoldenGate license, which is separate from Oracle GoldenGate license. There is no separate license for the Enterprise Manager Plug-in by itself. Oracle GoldenGate Monitor, Oracle GoldenGate Director, and Enterprise Manager Plug-in are included in the Management Pack for Oracle GoldenGate license. Please check out Management Pack for Oracle GoldenGate data sheet for more info on this product bundle. Q: Is Oracle GoldenGate replacing Oracle Streams product? A: Oracle GoldenGate is the strategic data replication product. Therefore, Oracle Streams will continue to be supported, but will not be actively enhanced. Rather, the best elements of Oracle Streams will be added to Oracle GoldenGate. Conflict management is one of them and with the latest release Oracle GoldenGate has a more advanced conflict management offering. Current customers depending on Oracle Streams will continue to be fully supported. Q: How is Oracle GoldenGate different than Oracle Data Integrator? A: Oracle Data Integrator is designed for fast bulk data movement and transformation between heterogeneous systems, while GoldenGate is designed for real-time movement of transactions between heterogeneous systems. These two products are completely complementary where GoldenGate provides low-impact real-time change data capture and delivery to a staging area on the target. And Oracle Data Integrator transforms this data and loads the DW tables. In fact, Oracle Data Integrator integrates with GoldenGate to use GoldenGate’s Capture process as one option for its CDC mechanism. We have several customers that deployed GoldenGate and ODI together to feed real-time data to their data warehousing solutions. Please also check out Oracle Data Integrator Changed Data Capture with Oracle GoldenGate Data Sheet (PDF). Thank you again very much for welcoming Oracle GoldenGate 11g Release 2 and stay in touch with us for more exciting news, updates, and events.

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  • CodePlex Daily Summary for Friday, April 23, 2010

    CodePlex Daily Summary for Friday, April 23, 2010New Projects3D TagCloud for SharePoint 2010: 3D Flash TagCloud WebPart for SharePoint 2010AnyCAD.Net: AnyCAD.NetCassandraemon: Cassandraemon is LINQ Provider for Apache Cassandra.CCLI SongSelect Importer for PowerPoint: CCLI SongSelect Importer for PowerPoint ® is an Add-in for Microsoft ® PowerPoint ® that allows CCLI SongSelect (USR) files to be turned into slide...Compactar Arquivo Txt, Flat File, em Pipeline Decoder Customizado: Objetivo do projeto: Desenvolver um componente do tipo Pipeline Receiver Decoder, onde compacta o conteúdo, cria uma mensagem em XML e transforma ...Console Calculator: Console calculator is a simple, yet useful, mathematical expression calculator, supporting functions and variables. It was created to demonstrate ...CRM Dynamics Excel Importer: CRM Dynamics Excel Importercubace: The standard audio composer software with just single difference: this is CLR compilation.deneb: deneb projectDrive Backup: Drive Backup is an easy to use, automatic backup program. Simply insert a USB drive, and the program will backup either files on the drive to your ...eWebMVCCMS: this is the start of eWeb MVC CMS.Fix.ly: Small app that allows for URL rewriting before passing to the browser. Accepts MEF plugins that make themselves available by informing the applicat...GArphics: GArphics uses a genetic algorithm to produce graphics and animation with the assitance of the user.JDS Toolkit: An experimental toolkit geared to make richer applications with less effort. It will include controls such as the cubeoid and the serializedmenu. ...KrashSRC - MapleStory v.75 Emulator: KrashSRC - MapleStory v.75 EmulatorLast.fm Api: Last.fm api writen in Visaul Basic 2010.MIX 10 DVR and Downloader: A Silverlight application that will manage downloading the sessions and slide decks from the MIX '10 Conference utilizing the MIX OData feed for in...NSIS Autorun: This is a graphical CD/DVD/USB autorun engine that launches installers made with NSIS. Non-rectangular windows and animation are supported. Can be ...Pillbox: Windows Phone 7 sample application for tracking medications.PowerSharp: Very simple application that executes a snippet of PowerShell against C#. This will eventually be used with Live@EDU.Project Halosis: mmorpgProyecto Cero: Proyecto CeroSharePoint XSL Templates: This project is a place to share useful XSL templates that can be reused in SharePoint CQWPs and DVWPs.Silverlight 4.0 Popup Menu: Silverlight 4.0 Popup Menu spsearch: This project provides useful enhancements to Search using the SharePoint platform.StereoVision: StereVision es un proyecto que estudia un algoritmo de visión estereocopicaThe Stoffenmanager: The Stoffenmanager is a tool for prioritizing worker health risks to dangerous substances. But also a quantitative inhalation exposure tool and a ...Transcriber: Transcribe text from one character set to another. Extensible, plug-in based architecture. Default plug-in uses XML rules files with regular expres...Wavelets experiments: эксперименты с вейвлетамиWindows Phone 7 World of Warcraft Armory Browser: A test project to learn a little about Windows Phone development and do a decent armory browserXAML Based Chat: Xaml based chat. A simple chat systemNew Releases#Nose: SharpNose v1.1: Configuration is now done by updating SharpNose.exe.config MEF support added - you can also add your favorite test framework discovery Two tes...Baml Localizer: Version 0.1 (alpha): This is the first release which should show the capabilities of Baml Localizer. The code might still change a lot, but the file formats should be q...BibWord : Microsoft Word Citation and Bibliography styles: APA with DOI - Proof of Concept: IntroductionThis release is a proof of concept (POC) demonstrating a possible way of adding a digital object identifier (DOI) field to the APA styl...Chargify.NET: Chargify.NET v0.685: Releasing Version 0.685 - Changed customer reference ID from Guid to String for systems that don't use Guid as the unique key. - Added method for g...Compactar Arquivo Txt, Flat File, em Pipeline Decoder Customizado: SampleZipDecodePipeline: Solution contem Projeto com o Decoder Pipeline. Projeto para usar o Componente. Classes SharpZipLib para compactar e descompactar arquivosConsole Calculator: Console Calculator: Initial source code release.CSharp Intellisense: V1.6: UPDATE: 2010/04/05: description was added 2010/04/07: single selection + reset filter 20010/04/15: source code available at http://csharpintellis...Drive Backup: Drive Backup: Drive Backup allows you to automatically backup a USB device to your computer, or backup files/directories on your computer to a USB. Once you have...Event Scavenger: Thread recycling changes - Version 3.1: Change the location of where the settings for thread recycling is stored - Moved from config file to database for easier management. Version of dat...Extend SmallBasic: Teaching Extensions v.013: Added Houses QuizExtend SmallBasic: Teaching Extensions v.014: fixed a bug in Tortoise.approve rearranged the Houses Quiz to be more funFix.ly: Fix.ly 0.1: Initial test releaseFix.ly: Fix.ly 0.11: Fixed a couple bugs, including missing files in the previous releaseGArphics: Beta: This is the beta-version of the program. Version 1.0 shall be relased soon and will include a lot of improvements.HouseFly: HouseFly alpha 0.2.0.5: HouseFly alpha release 0.2.0.5HouseFly controls: HouseFly controls alpha 0.9.4: Version 0.9.4 alpha release of HouseFly controlsHTML Ruby: 6.21.8: Change Math.floor to round for text spacingHTML Shot: 0.1: Solved problems with some URLsJDS Toolkit: JDS Toolkit 0.1: Beta 0.1 version. Almost nothing in these librariesManaged Extensibility Framework: WebForms and MEF Sample: This sample demonstrates the use of these two technologies together in a non-invasive way. Information on how to use it on your own projects is inc...Microsoft - Domain Oriented N-Layered .NET 4.0 App Sample (Microsoft Spain): V0.7 - N-Layer DDD Sample App (VS.2010 RTM compat): Required Software (Microsoft Base Software needed for Development environment) Visual Studio 2010 RTM & .NET 4.0 RTM (Final Versions) Unity Applic...MvcContrib Portable Areas: Portable Areas: First Release of some portable areasNSIS Autorun: NSIS Autorun: Initial release.OgmoXNA: OgmoXNA Alpha Source Tree: Zipped version of the source tree in case you don't want to go through the SVN!Particle Plot Pivot: Particle Plot Pivot v1.0.0: Generates a Pivot collection of unpublished plots from the particle physics exeriments DZERO, CDF, ATLAS, and CMS. It can be found at http://deepta...patterns & practices SharePoint Guidance: SPG2010 Drop9: SharePoint Guidance Drop Notes Microsoft patterns and practices ****************************************** ***************************************...Rich Ajax empowered Web/Cloud Applications: 6.3.15: New Visual WebGui rich applications platform versionSilverlight 4.0 Popup Menu: PopupMenu for Silverlight 4: This is the first release of the popup menu class for Silverlight 4.0Silverlight Flow Layouts library: SL and WPF Flow Layouts library April 2010: This release introduces WPF 4.0 RTM and Silverlight 4 RTM support, as well as an additional layout algorithm and some minor bug fixes. Some changes...Spackle.NET: 3.0.0.0 Release: In this release: Spackle.dll now targets the 4.0 version of the .NET Framework SecureRandom implements IDisposable ActionExtensions have been ...Splinger FrameXi: Splinger 1.1: Welcome to a whole new way of learning! Go to release 1.0 for the non .zip packaged files.SQL Server Metadata Toolkit 2008: SQL Server Metadata Toolkit Alpha 6: This release addresses issues 10665, 10678 and 10679. The SQL Parser now understands CAST functions (the AS was causing issues), and is installed ...Star Trooper for XNA 2D Tutorial: Lesson four content: Here is Lesson four original content for the StarTrooper 2D XNA tutorial. It also includes the XNA version of Lesson four source. The blog tutori...Thales Simulator Library: Version 0.8.6: The Thales Simulator Library is an implementation of a software emulation of the Thales (formerly Zaxus & Racal) Hardware Security Module cryptogra...Transcriber: Transcriber v0.1: Initial alpha release. Very nearly useful. :-) This version includes rules files for Mode of Beleriand, Sindarin Tehtar, Quenya, and Black Speech. ...Visual Studio DSite: Picture Box Viewer (Visual F sharp 2008): A simple picturebox viewer made in visual f sharp 2008.Web/Cloud Applications Development Framework | Visual WebGui: 6.4 Beta 2d: Further stabilization of the cutting-edge web applications frameworkWebAssert: WebAssert 0.1: Initial release. Supports HTML & CSS validation using MSTest/Visual Studio testing.XAML Based Chat: Test release: A test releaseすとれおじさん(仮): すとれおじさん β 0.02: ・デザインを大幅に変更 ・まだかなり動作が重いです ・機能も少ないですMost Popular ProjectsRawrWBFS ManagerSilverlight ToolkitAJAX Control ToolkitMicrosoft SQL Server Product Samples: Databasepatterns & practices – Enterprise LibraryWindows Presentation Foundation (WPF)ASP.NETMicrosoft SQL Server Community & SamplesPHPExcelMost Active Projectspatterns & practices – Enterprise LibraryRawrParticle Plot PivotBlogEngine.NETNB_Store - Free DotNetNuke Ecommerce Catalog ModuleGMap.NET - Great Maps for Windows Forms & PresentationFarseer Physics EngineDotNetZip LibraryFluent Ribbon Control SuiteN2 CMS

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  • C#/.NET Little Wonders: Fun With Enum Methods

    - by James Michael Hare
    Once again lets dive into the Little Wonders of .NET, those small things in the .NET languages and BCL classes that make development easier by increasing readability, maintainability, and/or performance. So probably every one of us has used an enumerated type at one time or another in a C# program.  The enumerated types we create are a great way to represent that a value can be one of a set of discrete values (or a combination of those values in the case of bit flags). But the power of enum types go far beyond simple assignment and comparison, there are many methods in the Enum class (that all enum types “inherit” from) that can give you even more power when dealing with them. IsDefined() – check if a given value exists in the enum Are you reading a value for an enum from a data source, but are unsure if it is actually a valid value or not?  Casting won’t tell you this, and Parse() isn’t guaranteed to balk either if you give it an int or a combination of flags.  So what can we do? Let’s assume we have a small enum like this for result codes we want to return back from our business logic layer: 1: public enum ResultCode 2: { 3: Success, 4: Warning, 5: Error 6: } In this enum, Success will be zero (unless given another value explicitly), Warning will be one, and Error will be two. So what happens if we have code like this where perhaps we’re getting the result code from another data source (could be database, could be web service, etc)? 1: public ResultCode PerformAction() 2: { 3: // set up and call some method that returns an int. 4: int result = ResultCodeFromDataSource(); 5:  6: // this will suceed even if result is < 0 or > 2. 7: return (ResultCode) result; 8: } So what happens if result is –1 or 4?  Well, the cast does not fail, so what we end up with would be an instance of a ResultCode that would have a value that’s outside of the bounds of the enum constants we defined. This means if you had a block of code like: 1: switch (result) 2: { 3: case ResultType.Success: 4: // do success stuff 5: break; 6:  7: case ResultType.Warning: 8: // do warning stuff 9: break; 10:  11: case ResultType.Error: 12: // do error stuff 13: break; 14: } That you would hit none of these blocks (which is a good argument for always having a default in a switch by the way). So what can you do?  Well, there is a handy static method called IsDefined() on the Enum class which will tell you if an enum value is defined.  1: public ResultCode PerformAction() 2: { 3: int result = ResultCodeFromDataSource(); 4:  5: if (!Enum.IsDefined(typeof(ResultCode), result)) 6: { 7: throw new InvalidOperationException("Enum out of range."); 8: } 9:  10: return (ResultCode) result; 11: } In fact, this is often recommended after you Parse() or cast a value to an enum as there are ways for values to get past these methods that may not be defined. If you don’t like the syntax of passing in the type of the enum, you could clean it up a bit by creating an extension method instead that would allow you to call IsDefined() off any isntance of the enum: 1: public static class EnumExtensions 2: { 3: // helper method that tells you if an enum value is defined for it's enumeration 4: public static bool IsDefined(this Enum value) 5: { 6: return Enum.IsDefined(value.GetType(), value); 7: } 8: }   HasFlag() – an easier way to see if a bit (or bits) are set Most of us who came from the land of C programming have had to deal extensively with bit flags many times in our lives.  As such, using bit flags may be almost second nature (for a quick refresher on bit flags in enum types see one of my old posts here). However, in higher-level languages like C#, the need to manipulate individual bit flags is somewhat diminished, and the code to check for bit flag enum values may be obvious to an advanced developer but cryptic to a novice developer. For example, let’s say you have an enum for a messaging platform that contains bit flags: 1: // usually, we pluralize flags enum type names 2: [Flags] 3: public enum MessagingOptions 4: { 5: None = 0, 6: Buffered = 0x01, 7: Persistent = 0x02, 8: Durable = 0x04, 9: Broadcast = 0x08 10: } We can combine these bit flags using the bitwise OR operator (the ‘|’ pipe character): 1: // combine bit flags using 2: var myMessenger = new Messenger(MessagingOptions.Buffered | MessagingOptions.Broadcast); Now, if we wanted to check the flags, we’d have to test then using the bit-wise AND operator (the ‘&’ character): 1: if ((options & MessagingOptions.Buffered) == MessagingOptions.Buffered) 2: { 3: // do code to set up buffering... 4: // ... 5: } While the ‘|’ for combining flags is easy enough to read for advanced developers, the ‘&’ test tends to be easy for novice developers to get wrong.  First of all you have to AND the flag combination with the value, and then typically you should test against the flag combination itself (and not just for a non-zero)!  This is because the flag combination you are testing with may combine multiple bits, in which case if only one bit is set, the result will be non-zero but not necessarily all desired bits! Thanks goodness in .NET 4.0 they gave us the HasFlag() method.  This method can be called from an enum instance to test to see if a flag is set, and best of all you can avoid writing the bit wise logic yourself.  Not to mention it will be more readable to a novice developer as well: 1: if (options.HasFlag(MessagingOptions.Buffered)) 2: { 3: // do code to set up buffering... 4: // ... 5: } It is much more concise and unambiguous, thus increasing your maintainability and readability. It would be nice to have a corresponding SetFlag() method, but unfortunately generic types don’t allow you to specialize on Enum, which makes it a bit more difficult.  It can be done but you have to do some conversions to numeric and then back to the enum which makes it less of a payoff than having the HasFlag() method.  But if you want to create it for symmetry, it would look something like this: 1: public static T SetFlag<T>(this Enum value, T flags) 2: { 3: if (!value.GetType().IsEquivalentTo(typeof(T))) 4: { 5: throw new ArgumentException("Enum value and flags types don't match."); 6: } 7:  8: // yes this is ugly, but unfortunately we need to use an intermediate boxing cast 9: return (T)Enum.ToObject(typeof (T), Convert.ToUInt64(value) | Convert.ToUInt64(flags)); 10: } Note that since the enum types are value types, we need to assign the result to something (much like string.Trim()).  Also, you could chain several SetFlag() operations together or create one that takes a variable arg list if desired. Parse() and ToString() – transitioning from string to enum and back Sometimes, you may want to be able to parse an enum from a string or convert it to a string - Enum has methods built in to let you do this.  Now, many may already know this, but may not appreciate how much power are in these two methods. For example, if you want to parse a string as an enum, it’s easy and works just like you’d expect from the numeric types: 1: string optionsString = "Persistent"; 2:  3: // can use Enum.Parse, which throws if finds something it doesn't like... 4: var result = (MessagingOptions)Enum.Parse(typeof (MessagingOptions), optionsString); 5:  6: if (result == MessagingOptions.Persistent) 7: { 8: Console.WriteLine("It worked!"); 9: } Note that Enum.Parse() will throw if it finds a value it doesn’t like.  But the values it likes are fairly flexible!  You can pass in a single value, or a comma separated list of values for flags and it will parse them all and set all bits: 1: // for string values, can have one, or comma separated. 2: string optionsString = "Persistent, Buffered"; 3:  4: var result = (MessagingOptions)Enum.Parse(typeof (MessagingOptions), optionsString); 5:  6: if (result.HasFlag(MessagingOptions.Persistent) && result.HasFlag(MessagingOptions.Buffered)) 7: { 8: Console.WriteLine("It worked!"); 9: } Or you can parse in a string containing a number that represents a single value or combination of values to set: 1: // 3 is the combination of Buffered (0x01) and Persistent (0x02) 2: var optionsString = "3"; 3:  4: var result = (MessagingOptions) Enum.Parse(typeof (MessagingOptions), optionsString); 5:  6: if (result.HasFlag(MessagingOptions.Persistent) && result.HasFlag(MessagingOptions.Buffered)) 7: { 8: Console.WriteLine("It worked again!"); 9: } And, if you really aren’t sure if the parse will work, and don’t want to handle an exception, you can use TryParse() instead: 1: string optionsString = "Persistent, Buffered"; 2: MessagingOptions result; 3:  4: // try parse returns true if successful, and takes an out parm for the result 5: if (Enum.TryParse(optionsString, out result)) 6: { 7: if (result.HasFlag(MessagingOptions.Persistent) && result.HasFlag(MessagingOptions.Buffered)) 8: { 9: Console.WriteLine("It worked!"); 10: } 11: } So we covered parsing a string to an enum, what about reversing that and converting an enum to a string?  The ToString() method is the obvious and most basic choice for most of us, but did you know you can pass a format string for enum types that dictate how they are written as a string?: 1: MessagingOptions value = MessagingOptions.Buffered | MessagingOptions.Persistent; 2:  3: // general format, which is the default, 4: Console.WriteLine("Default : " + value); 5: Console.WriteLine("G (default): " + value.ToString("G")); 6:  7: // Flags format, even if type does not have Flags attribute. 8: Console.WriteLine("F (flags) : " + value.ToString("F")); 9:  10: // integer format, value as number. 11: Console.WriteLine("D (num) : " + value.ToString("D")); 12:  13: // hex format, value as hex 14: Console.WriteLine("X (hex) : " + value.ToString("X")); Which displays: 1: Default : Buffered, Persistent 2: G (default): Buffered, Persistent 3: F (flags) : Buffered, Persistent 4: D (num) : 3 5: X (hex) : 00000003 Now, you may not really see a difference here between G and F because I used a [Flags] enum, the difference is that the “F” option treats the enum as if it were flags even if the [Flags] attribute is not present.  Let’s take a non-flags enum like the ResultCode used earlier: 1: // yes, we can do this even if it is not [Flags] enum. 2: ResultCode value = ResultCode.Warning | ResultCode.Error; And if we run that through the same formats again we get: 1: Default : 3 2: G (default): 3 3: F (flags) : Warning, Error 4: D (num) : 3 5: X (hex) : 00000003 Notice that since we had multiple values combined, but it was not a [Flags] marked enum, the G and default format gave us a number instead of a value name.  This is because the value was not a valid single-value constant of the enum.  However, using the F flags format string, it broke out the value into its component flags even though it wasn’t marked [Flags]. So, if you want to get an enum to display appropriately for whether or not it has the [Flags] attribute, use G which is the default.  If you always want it to attempt to break down the flags, use F.  For numeric output, obviously D or  X are the best choice depending on whether you want decimal or hex. Summary Hopefully, you learned a couple of new tricks with using the Enum class today!  I’ll add more little wonders as I think of them and thanks for all the invaluable input!   Technorati Tags: C#,.NET,Little Wonders,Enum,BlackRabbitCoder

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  • Why does Akonadi on KDE 4.6.0 refuse to start?

    - by Patches
    Akonadi refuses to start on my fresh installation of KDE 4.6.0 from the kubuntu-backports PPA on Ubuntu 10.10 Maverick Meerkat, preventing me from usking KMail. Here is the full error output: patches@pleistocene:~/.local/share$ akonadictl start Starting Akonadi Server... done. patches@pleistocene:~/.local/share$ Connecting to deprecated signal QDBusConnectionInterface::serviceOwnerChanged(QString,QString,QString) search paths: ("/home/patches/bin", "/usr/local/sbin", "/usr/local/bin", "/usr/sbin", "/usr/bin", "/sbin", "/bin", "/usr/games", "/usr/sbin", "/usr/local/sbin", "/usr/local/libexec", "/usr/libexec", "/opt/mysql/libexec", "/opt/local/lib/mysql5/bin", "/opt/mysql/sbin") Found mysql_install_db: "/usr/bin/mysql_install_db" Found mysqlcheck: "/usr/bin/mysqlcheck" Database process exited unexpectedly during initial connection! executable: "/usr/sbin/mysqld-akonadi" arguments: ("--defaults-file=/home/patches/.local/share/akonadi//mysql.conf", "--datadir=/home/patches/.local/share/akonadi/db_data/", "--socket=/home/patches/.local/share/akonadi/socket-pleistocene/mysql.socket") stdout: "" stderr: "Could not open required defaults file: /home/patches/.local/share/akonadi//mysql.conf Fatal error in defaults handling. Program aborted 110209 16:41:12 [Warning] Can't create test file /home/patches/.local/share/akonadi/db_data/pleistocene.lower-test 110209 16:41:12 [Warning] Can't create test file /home/patches/.local/share/akonadi/db_data/pleistocene.lower-test 110209 16:41:12 [Note] Plugin 'FEDERATED' is disabled. /usr/sbin/mysqld-akonadi: Can't find file: './mysql/plugin.frm' (errno: 13) 110209 16:41:12 [ERROR] Can't open the mysql.plugin table. Please run mysql_upgrade to create it. 110209 16:41:12 InnoDB: Operating system error number 13 in a file operation. InnoDB: The error means mysqld does not have the access rights to InnoDB: the directory. InnoDB: File name ./ibdata1 InnoDB: File operation call: 'create'. InnoDB: Cannot continue operation. " exit code: 1 process error: "Unknown error" "[ 0: akonadiserver(_Z11akBacktracev+0x35) [0x8086055] 1: akonadiserver() [0x8086516] 2: [0xb772e400] 3: [0xb772e416] 4: /lib/libc.so.6(gsignal+0x51) [0xb6e9f941] 5: /lib/libc.so.6(abort+0x182) [0xb6ea2e42] 6: /usr/lib/libQtCore.so.4(_Z17qt_message_output9QtMsgTypePKc+0x8c) [0xb74d62dc] 7: akonadiserver(_ZN15FileDebugStream9writeDataEPKcx+0xc4) [0x8087574] 8: /usr/lib/libQtCore.so.4(_ZN9QIODevice5writeEPKcx+0x8e) [0xb757168e] 9: /usr/lib/libQtCore.so.4(+0x103425) [0xb7581425] 10: /usr/lib/libQtCore.so.4(_ZN11QTextStreamD1Ev+0x3d) [0xb758295d] 11: akonadiserver(_ZN6QDebugD1Ev+0x43) [0x8081b73] 12: akonadiserver(_ZN13DbConfigMysql19startInternalServerEv+0x1c27) [0x810c177] 13: akonadiserver(_ZN7Akonadi13AkonadiServer20startDatabaseProcessEv+0xe3) [0x8087a23] 14: akonadiserver(_ZN7Akonadi13AkonadiServerC1EP7QObject+0xca) [0x8088b6a] 15: akonadiserver(_ZN7Akonadi13AkonadiServer8instanceEv+0x48) [0x808a1d8] 16: akonadiserver(main+0x364) [0x8080fb4] 17: /lib/libc.so.6(__libc_start_main+0xe7) [0xb6e8bce7] 18: akonadiserver() [0x8080b81] ] " ProcessControl: Application 'akonadiserver' returned with exit code 255 (Unknown error) search paths: ("/home/patches/bin", "/usr/local/sbin", "/usr/local/bin", "/usr/sbin", "/usr/bin", "/sbin", "/bin", "/usr/games", "/usr/sbin", "/usr/local/sbin", "/usr/local/libexec", "/usr/libexec", "/opt/mysql/libexec", "/opt/local/lib/mysql5/bin", "/opt/mysql/sbin") Found mysql_install_db: "/usr/bin/mysql_install_db" Found mysqlcheck: "/usr/bin/mysqlcheck" Database process exited unexpectedly during initial connection! executable: "/usr/sbin/mysqld-akonadi" arguments: ("--defaults-file=/home/patches/.local/share/akonadi//mysql.conf", "--datadir=/home/patches/.local/share/akonadi/db_data/", "--socket=/home/patches/.local/share/akonadi/socket-pleistocene/mysql.socket") stdout: "" stderr: "Could not open required defaults file: /home/patches/.local/share/akonadi//mysql.conf Fatal error in defaults handling. Program aborted 110209 16:41:12 [Warning] Can't create test file /home/patches/.local/share/akonadi/db_data/pleistocene.lower-test 110209 16:41:12 [Warning] Can't create test file /home/patches/.local/share/akonadi/db_data/pleistocene.lower-test 110209 16:41:12 [Note] Plugin 'FEDERATED' is disabled. /usr/sbin/mysqld-akonadi: Can't find file: './mysql/plugin.frm' (errno: 13) 110209 16:41:12 [ERROR] Can't open the mysql.plugin table. Please run mysql_upgrade to create it. 110209 16:41:12 InnoDB: Operating system error number 13 in a file operation. InnoDB: The error means mysqld does not have the access rights to InnoDB: the directory. InnoDB: File name ./ibdata1 InnoDB: File operation call: 'create'. InnoDB: Cannot continue operation. " exit code: 1 process error: "Unknown error" "[ 0: akonadiserver(_Z11akBacktracev+0x35) [0x8086055] 1: akonadiserver() [0x8086516] 2: [0xb77ae400] 3: [0xb77ae416] 4: /lib/libc.so.6(gsignal+0x51) [0xb6f1f941] 5: /lib/libc.so.6(abort+0x182) [0xb6f22e42] 6: /usr/lib/libQtCore.so.4(_Z17qt_message_output9QtMsgTypePKc+0x8c) [0xb75562dc] 7: akonadiserver(_ZN15FileDebugStream9writeDataEPKcx+0xc4) [0x8087574] 8: /usr/lib/libQtCore.so.4(_ZN9QIODevice5writeEPKcx+0x8e) [0xb75f168e] 9: /usr/lib/libQtCore.so.4(+0x103425) [0xb7601425] 10: /usr/lib/libQtCore.so.4(_ZN11QTextStreamD1Ev+0x3d) [0xb760295d] 11: akonadiserver(_ZN6QDebugD1Ev+0x43) [0x8081b73] 12: akonadiserver(_ZN13DbConfigMysql19startInternalServerEv+0x1c27) [0x810c177] 13: akonadiserver(_ZN7Akonadi13AkonadiServer20startDatabaseProcessEv+0xe3) [0x8087a23] 14: akonadiserver(_ZN7Akonadi13AkonadiServerC1EP7QObject+0xca) [0x8088b6a] 15: akonadiserver(_ZN7Akonadi13AkonadiServer8instanceEv+0x48) [0x808a1d8] 16: akonadiserver(main+0x364) [0x8080fb4] 17: /lib/libc.so.6(__libc_start_main+0xe7) [0xb6f0bce7] 18: akonadiserver() [0x8080b81] ] " ProcessControl: Application 'akonadiserver' returned with exit code 255 (Unknown error) search paths: ("/home/patches/bin", "/usr/local/sbin", "/usr/local/bin", "/usr/sbin", "/usr/bin", "/sbin", "/bin", "/usr/games", "/usr/sbin", "/usr/local/sbin", "/usr/local/libexec", "/usr/libexec", "/opt/mysql/libexec", "/opt/local/lib/mysql5/bin", "/opt/mysql/sbin") Found mysql_install_db: "/usr/bin/mysql_install_db" Found mysqlcheck: "/usr/bin/mysqlcheck" Database process exited unexpectedly during initial connection! executable: "/usr/sbin/mysqld-akonadi" arguments: ("--defaults-file=/home/patches/.local/share/akonadi//mysql.conf", "--datadir=/home/patches/.local/share/akonadi/db_data/", "--socket=/home/patches/.local/share/akonadi/socket-pleistocene/mysql.socket") stdout: "" stderr: "Could not open required defaults file: /home/patches/.local/share/akonadi//mysql.conf Fatal error in defaults handling. Program aborted 110209 16:41:12 [Warning] Can't create test file /home/patches/.local/share/akonadi/db_data/pleistocene.lower-test 110209 16:41:12 [Warning] Can't create test file /home/patches/.local/share/akonadi/db_data/pleistocene.lower-test 110209 16:41:12 [Note] Plugin 'FEDERATED' is disabled. /usr/sbin/mysqld-akonadi: Can't find file: './mysql/plugin.frm' (errno: 13) 110209 16:41:12 [ERROR] Can't open the mysql.plugin table. Please run mysql_upgrade to create it. 110209 16:41:12 InnoDB: Operating system error number 13 in a file operation. InnoDB: The error means mysqld does not have the access rights to InnoDB: the directory. InnoDB: File name ./ibdata1 InnoDB: File operation call: 'create'. InnoDB: Cannot continue operation. " exit code: 1 process error: "Unknown error" "[ 0: akonadiserver(_Z11akBacktracev+0x35) [0x8086055] 1: akonadiserver() [0x8086516] 2: [0xb778b400] 3: [0xb778b416] 4: /lib/libc.so.6(gsignal+0x51) [0xb6efc941] 5: /lib/libc.so.6(abort+0x182) [0xb6effe42] 6: /usr/lib/libQtCore.so.4(_Z17qt_message_output9QtMsgTypePKc+0x8c) [0xb75332dc] 7: akonadiserver(_ZN15FileDebugStream9writeDataEPKcx+0xc4) [0x8087574] 8: /usr/lib/libQtCore.so.4(_ZN9QIODevice5writeEPKcx+0x8e) [0xb75ce68e] 9: /usr/lib/libQtCore.so.4(+0x103425) [0xb75de425] 10: /usr/lib/libQtCore.so.4(_ZN11QTextStreamD1Ev+0x3d) [0xb75df95d] 11: akonadiserver(_ZN6QDebugD1Ev+0x43) [0x8081b73] 12: akonadiserver(_ZN13DbConfigMysql19startInternalServerEv+0x1c27) [0x810c177] 13: akonadiserver(_ZN7Akonadi13AkonadiServer20startDatabaseProcessEv+0xe3) [0x8087a23] 14: akonadiserver(_ZN7Akonadi13AkonadiServerC1EP7QObject+0xca) [0x8088b6a] 15: akonadiserver(_ZN7Akonadi13AkonadiServer8instanceEv+0x48) [0x808a1d8] 16: akonadiserver(main+0x364) [0x8080fb4] 17: /lib/libc.so.6(__libc_start_main+0xe7) [0xb6ee8ce7] 18: akonadiserver() [0x8080b81] ] " ProcessControl: Application 'akonadiserver' returned with exit code 255 (Unknown error) search paths: ("/home/patches/bin", "/usr/local/sbin", "/usr/local/bin", "/usr/sbin", "/usr/bin", "/sbin", "/bin", "/usr/games", "/usr/sbin", "/usr/local/sbin", "/usr/local/libexec", "/usr/libexec", "/opt/mysql/libexec", "/opt/local/lib/mysql5/bin", "/opt/mysql/sbin") Found mysql_install_db: "/usr/bin/mysql_install_db" Found mysqlcheck: "/usr/bin/mysqlcheck" Database process exited unexpectedly during initial connection! executable: "/usr/sbin/mysqld-akonadi" arguments: ("--defaults-file=/home/patches/.local/share/akonadi//mysql.conf", "--datadir=/home/patches/.local/share/akonadi/db_data/", "--socket=/home/patches/.local/share/akonadi/socket-pleistocene/mysql.socket") stdout: "" stderr: "Could not open required defaults file: /home/patches/.local/share/akonadi//mysql.conf Fatal error in defaults handling. Program aborted 110209 16:41:12 [Warning] Can't create test file /home/patches/.local/share/akonadi/db_data/pleistocene.lower-test 110209 16:41:12 [Warning] Can't create test file /home/patches/.local/share/akonadi/db_data/pleistocene.lower-test 110209 16:41:12 [Note] Plugin 'FEDERATED' is disabled. /usr/sbin/mysqld-akonadi: Can't find file: './mysql/plugin.frm' (errno: 13) 110209 16:41:12 [ERROR] Can't open the mysql.plugin table. Please run mysql_upgrade to create it. 110209 16:41:12 InnoDB: Operating system error number 13 in a file operation. InnoDB: The error means mysqld does not have the access rights to InnoDB: the directory. InnoDB: File name ./ibdata1 InnoDB: File operation call: 'create'. InnoDB: Cannot continue operation. " exit code: 1 process error: "Unknown error" "[ 0: akonadiserver(_Z11akBacktracev+0x35) [0x8086055] 1: akonadiserver() [0x8086516] 2: [0xb784e400] 3: [0xb784e416] 4: /lib/libc.so.6(gsignal+0x51) [0xb6fbf941] 5: /lib/libc.so.6(abort+0x182) [0xb6fc2e42] 6: /usr/lib/libQtCore.so.4(_Z17qt_message_output9QtMsgTypePKc+0x8c) [0xb75f62dc] 7: akonadiserver(_ZN15FileDebugStream9writeDataEPKcx+0xc4) [0x8087574] 8: /usr/lib/libQtCore.so.4(_ZN9QIODevice5writeEPKcx+0x8e) [0xb769168e] 9: /usr/lib/libQtCore.so.4(+0x103425) [0xb76a1425] 10: /usr/lib/libQtCore.so.4(_ZN11QTextStreamD1Ev+0x3d) [0xb76a295d] 11: akonadiserver(_ZN6QDebugD1Ev+0x43) [0x8081b73] 12: akonadiserver(_ZN13DbConfigMysql19startInternalServerEv+0x1c27) [0x810c177] 13: akonadiserver(_ZN7Akonadi13AkonadiServer20startDatabaseProcessEv+0xe3) [0x8087a23] 14: akonadiserver(_ZN7Akonadi13AkonadiServerC1EP7QObject+0xca) [0x8088b6a] 15: akonadiserver(_ZN7Akonadi13AkonadiServer8instanceEv+0x48) [0x808a1d8] 16: akonadiserver(main+0x364) [0x8080fb4] 17: /lib/libc.so.6(__libc_start_main+0xe7) [0xb6fabce7] 18: akonadiserver() [0x8080b81] ] " ProcessControl: Application 'akonadiserver' returned with exit code 255 (Unknown error) "akonadiserver" crashed too often and will not be restarted! I tried moving the ~/.local/share/akonadi folder and running it fresh, and I also tried starting Akonadi from a brand new user, all to no avail. Requested by @djeikyb: patches@pleistocene:~$ ls -ld ~/.local drwxrwx--- 3 patches patches 4096 2011-02-07 03:15 /home/patches/.local patches@pleistocene:~$ mysql_upgrade Looking for 'mysql' as: mysql Looking for 'mysqlcheck' as: mysqlcheck Running 'mysqlcheck' with connection arguments: '--port=3306' '--socket=/var/run/mysqld/mysqld.sock' mysqlcheck: Got error: 2002: Can't connect to local MySQL server through socket '/var/run/mysqld/mysqld.sock' (2) when trying to connect FATAL ERROR: Upgrade failed patches@pleistocene:~$ mysql_upgrade -S ~/.local/share/akonadi/socket-pleistocene/ Looking for 'mysql' as: mysql Looking for 'mysqlcheck' as: mysqlcheck Running 'mysqlcheck' with connection arguments: '--port=3306' '--socket=/var/run/mysqld/mysqld.sock' '--socket=/home/patches/.local/share/akonadi/socket-pleistocene/' mysqlcheck: Got error: 2002: Can't connect to local MySQL server through socket '/home/patches/.local/share/akonadi/socket-pleistocene/' (111) when trying to connect FATAL ERROR: Upgrade failed

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  • Pre-rentrée Oracle Open World 2012 : à vos agendas

    - by Eric Bezille
    A maintenant moins d'un mois de l’événement majeur d'Oracle, qui se tient comme chaque année à San Francisco, fin septembre, début octobre, les spéculations vont bon train sur les annonces qui vont y être dévoilées... Et sans lever le voile, je vous engage à prendre connaissance des sujets des "Key Notes" qui seront tenues par Larry Ellison, Mark Hurd, Thomas Kurian (responsable des développements logiciels) et John Fowler (responsable des développements systèmes) afin de vous donner un avant goût. Stratégie et Roadmaps Oracle Bien entendu, au-delà des séances plénières qui vous donnerons  une vision précise de la stratégie, et pour ceux qui seront sur place, je vous engage à ne pas manquer les séances d'approfondissement qui auront lieu dans la semaine, dont voici quelques morceaux choisis : "Accelerate your Business with the Oracle Hardware Advantage" avec John Fowler, le lundi 1er Octobre, 3:15pm-4:15pm "Why Oracle Softwares Runs Best on Oracle Hardware" , avec Bradley Carlile, le responsable des Benchmarks, le lundi 1er Octobre, 12:15pm-13:15pm "Engineered Systems - from Vision to Game-changing Results", avec Robert Shimp, le lundi 1er Octobre 1:45pm-2:45pm "Database and Application Consolidation on SPARC Supercluster", avec Hugo Rivero, responsable dans les équipes d'intégration matériels et logiciels, le lundi 1er Octobre, 4:45pm-5:45pm "Oracle’s SPARC Server Strategy Update", avec Masood Heydari, responsable des développements serveurs SPARC, le mardi 2 Octobre, 10:15am - 11:15am "Oracle Solaris 11 Strategy, Engineering Insights, and Roadmap", avec Markus Flier, responsable des développements Solaris, le mercredi 3 Octobre, 10:15am - 11:15am "Oracle Virtualization Strategy and Roadmap", avec Wim Coekaerts, responsable des développement Oracle VM et Oracle Linux, le lundi 1er Octobre, 12:15pm-1:15pm "Big Data: The Big Story", avec Jean-Pierre Dijcks, responsable du développement produits Big Data, le lundi 1er Octobre, 3:15pm-4:15pm "Scaling with the Cloud: Strategies for Storage in Cloud Deployments", avec Christine Rogers,  Principal Product Manager, et Chris Wood, Senior Product Specialist, Stockage , le lundi 1er Octobre, 10:45am-11:45am Retours d'expériences et témoignages Si Oracle Open World est l'occasion de partager avec les équipes de développement d'Oracle en direct, c'est aussi l'occasion d'échanger avec des clients et experts qui ont mis en oeuvre  nos technologies pour bénéficier de leurs retours d'expériences, comme par exemple : "Oracle Optimized Solution for Siebel CRM at ACCOR", avec les témoignages d'Eric Wyttynck, directeur IT Multichannel & CRM  et Pascal Massenet, VP Loyalty & CRM systems, sur les bénéfices non seulement métiers, mais également projet et IT, le mercredi 3 Octobre, 1:15pm-2:15pm "Tips from AT&T: Oracle E-Business Suite, Oracle Database, and SPARC Enterprise", avec le retour d'expérience des experts Oracle, le mardi 2 Octobre, 11:45am-12:45pm "Creating a Maximum Availability Architecture with SPARC SuperCluster", avec le témoignage de Carte Wright, Database Engineer à CKI, le mercredi 3 Octobre, 11:45am-12:45pm "Multitenancy: Everybody Talks It, Oracle Walks It with Pillar Axiom Storage", avec le témoignage de Stephen Schleiger, Manager Systems Engineering de Navis, le lundi 1er Octobre, 1:45pm-2:45pm "Oracle Exadata for Database Consolidation: Best Practices", avec le retour d'expérience des experts Oracle ayant participé à la mise en oeuvre d'un grand client du monde bancaire, le lundi 1er Octobre, 4:45pm-5:45pm "Oracle Exadata Customer Panel: Packaged Applications with Oracle Exadata", animé par Tim Shetler, VP Product Management, mardi 2 Octobre, 1:15pm-2:15pm "Big Data: Improving Nearline Data Throughput with the StorageTek SL8500 Modular Library System", avec le témoignage du CTO de CSC, Alan Powers, le jeudi 4 Octobre, 12:45pm-1:45pm "Building an IaaS Platform with SPARC, Oracle Solaris 11, and Oracle VM Server for SPARC", avec le témoignage de Syed Qadri, Lead DBA et Michael Arnold, System Architect d'US Cellular, le mardi 2 Octobre, 10:15am-11:15am "Transform Data Center TCO with Oracle Optimized Servers: A Customer Panel", avec les témoignages notamment d'AT&T et Liberty Global, le mardi 2 Octobre, 11:45am-12:45pm "Data Warehouse and Big Data Customers’ View of the Future", avec The Nielsen Company US, Turkcell, GE Retail Finance, Allianz Managed Operations and Services SE, le lundi 1er Octobre, 4:45pm-5:45pm "Extreme Storage Scale and Efficiency: Lessons from a 100,000-Person Organization", le témoignage de l'IT interne d'Oracle sur la transformation et la migration de l'ensemble de notre infrastructure de stockage, mardi 2 Octobre, 1:15pm-2:15pm Echanges avec les groupes d'utilisateurs et les équipes de développement Oracle Si vous avez prévu d'arriver suffisamment tôt, vous pourrez également échanger dès le dimanche avec les groupes d'utilisateurs, ou tous les soirs avec les équipes de développement Oracle sur des sujets comme : "To Exalogic or Not to Exalogic: An Architectural Journey", avec Todd Sheetz - Manager of DBA and Enterprise Architecture, Veolia Environmental Services, le dimanche 30 Septembre, 2:30pm-3:30pm "Oracle Exalytics and Oracle TimesTen for Exalytics Best Practices", avec Mark Rittman, de Rittman Mead Consulting Ltd, le dimanche 30 Septembre, 10:30am-11:30am "Introduction of Oracle Exadata at Telenet: Bringing BI to Warp Speed", avec Rudy Verlinden & Eric Bartholomeus - Managers IT infrastructure à Telenet, le dimanche 30 Septembre, 1:15pm-2:00pm "The Perfect Marriage: Sun ZFS Storage Appliance with Oracle Exadata", avec Melanie Polston, directeur, Data Management, de Novation et Charles Kim, Managing Director de Viscosity, le dimanche 30 Septembre, 9:00am-10am "Oracle’s Big Data Solutions: NoSQL, Connectors, R, and Appliance Technologies", avec Jean-Pierre Dijcks et les équipes de développement Oracle, le lundi 1er Octobre, 6:15pm-7:00pm Testez et évaluez les solutions Et pour finir, vous pouvez même tester les technologies au travers du Oracle DemoGrounds, (1133 Moscone South pour la partie Systèmes Oracle, OS, et Virtualisation) et des "Hands-on-Labs", comme : "Deploying an IaaS Environment with Oracle VM", le mardi 2 Octobre, 10:15am-11:15am "Virtualize and Deploy Oracle Applications in Minutes with Oracle VM: Hands-on Lab", le mardi 2 Octobre, 11:45am-12:45pm (il est fortement conseillé d'avoir suivi le "Hands-on-Labs" précédent avant d'effectuer ce Lab. "x86 Enterprise Cloud Infrastructure with Oracle VM 3.x and Sun ZFS Storage Appliance", le mercredi 3 Octobre, 5:00pm-6:00pm "StorageTek Tape Analytics: Managing Tape Has Never Been So Simple", le mercredi 3 Octobre, 1:15pm-2:15pm "Oracle’s Pillar Axiom 600 Storage System: Power and Ease", le lundi 1er Octobre, 12:15pm-1:15pm "Enterprise Cloud Infrastructure for SPARC with Oracle Enterprise Manager Ops Center 12c", le lundi 1er Octobre, 1:45pm-2:45pm "Managing Storage in the Cloud", le mardi 2 Octobre, 5:00pm-6:00pm "Learn How to Write MapReduce on Oracle’s Big Data Platform", le lundi 1er Octobre, 12:15pm-1:15pm "Oracle Big Data Analytics and R", le mardi 2 Octobre, 1:15pm-2:15pm "Reduce Risk with Oracle Solaris Access Control to Restrain Users and Isolate Applications", le lundi 1er Octobre, 10:45am-11:45am "Managing Your Data with Built-In Oracle Solaris ZFS Data Services in Release 11", le lundi 1er Octobre, 4:45pm-5:45pm "Virtualizing Your Oracle Solaris 11 Environment", le mardi 2 Octobre, 1:15pm-2:15pm "Large-Scale Installation and Deployment of Oracle Solaris 11", le mercredi 3 Octobre, 3:30pm-4:30pm En conclusion, une semaine très riche en perspective, et qui vous permettra de balayer l'ensemble des sujets au coeur de vos préoccupations, de la stratégie à l'implémentation... Cette semaine doit se préparer, pour tailler votre agenda sur mesure, à travers les plus de 2000 sessions dont je ne vous ai fait qu'un extrait, et dont vous pouvez retrouver l'ensemble en ligne.

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  • Graph Theory: How to compute closeness centrality for each node in a set of data?

    - by Jordan
    I'd like to learn how to apply network theory to my own cache of relational data. I'm trying to build a demo of a new way of browsing a music library, using network theory, that I think would make for a very intuitive and useful way of finding the right song at any given time. I have all the data (artists as nodes, similarity from 0 to 1 between each artist and those it is related to) and I can already program, but I don't know how to actually calculate the centrality of a node from that. I've spent a while trying to email different professors at my school but no one seems to know where I can learn this. I hope someone's done something similar. Thanks in advance you guys! ~Jordan

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  • Notify DataTemplateSelector about the change

    - by Tigran
    I use DataTemplateSelector for ListView column headers template selection. ListView itself is in DataTemplate and ends up in a few tabs. So, in practice, I have same DataTemplate (so ListView too) shared between more TabItems. This means that if I select tab {A} and set XDataTemplate on ListView column {AColumn}, if I switch the tab, lets say to tab {B}, on {B}'s ListView (that is always the same one) column {AColumn} we will see the same XDataTemplate, because we share same UI data. So I created data layer where I hold relational information about {Tab} <- {ListView:Column} <- {HeaderContent}, which actually reads DatatemplateSelector in order correctly update UI on user screen. What I need is to notify to DataTemplateSelector to update current view in the moment that I need. How can I achieve that goal? Thank you.

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  • Foreign key onto weak entity set in MS SQL Server 2008?

    - by Nic Waller
    I'm using Microsoft SQL Server 2008 Management Studio to create a relational schema by following an Entity-Relationship diagram. (included below; unrelated details removed) Until now, primary and foreign keys have been working as expected. But when I try to create a foreign key from the entity relationship takes onto the weak entity set section, I get an error. Section is identified by a composite primary key in the context of course, which has course_id as a primary key. Therefore, the primary key of section is a 4-way composite key. The entity relationship takes needs to refer to section, so it includes all 4 primary attributes from section in it's own primary key. When trying to establish a foreign key relationship from takes to section, Studio gives the following error: The columns in table 'section' do not match an existing primary key or UNIQUE constraint. Am I doing something wrong, or is this an unsupported configuration? I can provide more details or the SQL schema if necessary.

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  • css: zoooming-out inside the browser moves rightmost floated div below other divs

    - by John Sonderson
    I am seeing something strange in both firefox and chrome when I increase the zoom level inside these browsers, although I see nothing wrong with my CSS... I am hoping someone on this group will be able to help. Here is the whole story: I have a right-floated top-level div containing three right-floated right. The three inner divs have all box-model measurements in pixels which add up to the width of the enclosing container. Everything looks fine when the browser size is 100%, but when I start making the browser smaller with CTRL+scrollwheel or CTRL+minus the rightmost margin shrinks down too fast and eventually becomes zero, forcing my rightmost floated inner div to fall down below the other two! I can't make sense out of this, almost seems like some integer division is being performed incorrectly in the browser code, but alas firefox and chrome both display the same result. Here is the example (just zoom out with CTRL-minus to see what I mean): Click Here to View What I Mean on Example Site Just to narrow things down a bit, the tags of interest are the following: div#mainContent div#contentLeft div#contentCenter div#contentRight I've searched stackoverflow for an answer and found the following posts which seem related to my question but was not able to apply them to the problem I am experiencing: http:// stackoverflow.com/questions/6955313/div-moves-incorrectly-on-browser-resize http:// stackoverflow.com/questions/18246882/divs-move-when-resizing-page http:// stackoverflow.com/questions/17637231/moving-an-image-when-browser-resizes http:// stackoverflow.com/questions/5316380/how-to-stop-divs-moving-when-the-browser-is-resized I've duplicated the html and css code below for your convenience: Here is the HTML: <!doctype html> <html> <head> <meta charset="utf-8"> <title>Pinco</title> <link href="css/style.css" rel="stylesheet" type="text/css"> </head> <body> <div id="wrapper"> <header> <div class="logo"> <a href="http://pinco.com"> <img class="logo" src="images/PincoLogo5.png" alt="Pinco" /> </a> </div> <div class="titolo"> <h1>Benvenuti!</h1> <h2>Siete arrivati al sito pinco.</h2> </div> <nav> <ul class="menu"> <li><a href="#">Menù Qui</a></li> <li><a href="#">Menù Quo</a></li> <li><a href="#">Menù Qua</a></li> </ul> </nav> </header> <div id="mainContent"> <div id="contentLeft"> <section> <article> <p> Lorem ipsum dolor sit amet, consectetur adipiscing elit. Quisque tempor turpis est, nec varius est pharetra scelerisque. Sed eu pellentesque purus, at cursus nisi. In bibendum tristique nunc eu mattis. Nulla pretium tincidunt ipsum, non imperdiet metus tincidunt ac. In et lobortis elit, nec lobortis purus. Cras ac viverra risus. Proin dapibus tortor justo, a vulputate ipsum lacinia sed. In hac habitasse platea dictumst. Phasellus sit amet malesuada velit. Fusce diam neque, cursus id dui ac, blandit vehicula tortor. Phasellus interdum ipsum eu leo condimentum, in dignissim erat tincidunt. Ut fermentum consectetur tellus, dignissim volutpat orci suscipit ac. Praesent scelerisque urna metus. Vestibulum ante ipsum primis in faucibus orci luctus et ultrices posuere cubilia Curae; Duis pulvinar, sem a sodales eleifend, odio elit blandit risus, a dapibus ligula orci non augue. Nullam vitae cursus tortor, eget malesuada lectus. Nulla facilisi. Cras pharetra nisi sit amet orci dignissim, a eleifend odio hendrerit. </p> </article> </section> </div> <div id="contentCenter"> <section> <article> <p> Maecenas vitae purus at orci euismod pretium. Nam gravida gravida bibendum. Donec nec dolor vel magna consequat laoreet in a urna. Phasellus cursus ultrices lorem ut sagittis. Class aptent taciti sociosqu ad litora torquent per conubia nostra, per inceptos himenaeos. Vivamus purus felis, ornare quis ante vel, commodo scelerisque tortor. Integer vel facilisis mauris. </p> <img src="images/auto1.jpg" width="272" height="272" /> <p> In urna purus, fringilla a urna a, ultrices convallis orci. Duis mattis sit amet leo sed luctus. Donec nec sem non nunc mattis semper quis vitae enim. Cum sociis natoque penatibus et magnis dis parturient montes, nascetur ridiculus mus. Suspendisse dictum porta quam, vel lobortis enim bibendum et. Donec iaculis tortor id metus interdum, hendrerit tincidunt orci tempor. Sed dignissim cursus mattis. </p> </article> </section> </div> <div id="contentRight"> <section> <article> <img src="images/auto2.jpg" width="272" height="272" /> <img src="images/auto3.jpg" width="272" height="272" /> <p> Cras eu quam lobortis, sodales felis ultricies, rhoncus neque. Aenean nisi eros, blandit ac lacus sit amet, vulputate sodales mi. Nunc eget purus ultricies, aliquam quam sit amet, porttitor velit. In imperdiet justo in quam tristique, eget semper nisi pellentesque. Cras fringilla eros enim, in euismod nisl imperdiet ac. Fusce tempor justo vitae faucibus luctus. </p> </article> </section> </div> </div> <footer> <div class="footerText"> <p> Copyright &copy; Pinco <br />Lorem ipsum dolor sit amet, consectetur adipiscing elit. <br />Fusce ornare turpis orci, nec egestas leo feugiat ac. <br />Morbi eget sem facilisis, laoreet erat ut, tristique odio. Proin sollicitudin quis nisi id consequat. </p> </div> <div class="footerLogo"> <img class="footerLogo" src="images/auto4.jpg" width="80" height="80" /> </div> </footer> </div> </body> </html> and here is the CSS: /* CSS Document */ * { margin: 0; border: 0; padding: 0; } body { background: #8B0000; /* darkred */; } body { margin: 0; border: 0; padding: 0; } div#wrapper { margin: 0 auto; width: 960px; height: 100%; background: #FFC0CB /* pink */; } header { position: relative; background: #005b97; height: 140px; } header div.logo { float: left; width: 360px; height: 140px; } header div.logo img.logo { width: 360px; height: 140px; } header div.titolo { float: left; padding: 12px 0 0 35px; color: black; } header div.titolo h1 { font-size: 36px; font-weight: bold; } header div.titolo h2 { font-size: 24px; font-style: italic; font-weight: bold; color: white;} header nav { position: absolute; right: 0; bottom: 0; } header ul.menu { background: black; } header ul.menu li { display: inline-block; padding: 3px 15px; font-weight: bold; } div#mainContent { float: left; width: 100%; /* width: 960px; *//* height: 860px; */ padding: 30px 0; text-align: justify; } div#mainContent img { margin: 12px 0; } div#contentLeft { height: 900px; float: left; margin-left: 12px; border: 1px solid black; padding: 15px; width: 272px; background: #ccc; } div#contentCenter { height: 900px; float: left; margin-left: 12px; border: 1px solid transparent; padding: 15px; width: 272px; background: #E00; } div#contentRight { height: 900px; float: left; margin-left: 12px; border: 1px solid black; padding: 15px; width: 272px; background: #ccc; } footer { clear: both; padding: 12px; background: #306; color: white; height: 80px; font-style: italic; font-weight: bold; } footer div.footerText { float: left; } footer div.footerLogo { float: right; } a { color: white; text-decoration: none; } Thanks.

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  • Legal uses of setjmp and GCC

    - by Chris Lutz
    Using GCC (4.0 for me), is this legal: if(__builtin_expect(setjmp(buf) != 0, 1)) { // handle error } else { // do action } I found a discussion saying it caused a problem for GCC back in 2003, but I would imagine that they would have fixed it by now. The C standard says that it's illegal to use setjmp unless it's one of four conditions, the relevant one being this: one operand of a relational or equality operator with the other operand an integer constant expression, with the resulting expression being the entire controlling expression of a selection or iteration statement; But if this is a GCC extension, can I guarantee that it will work under for GCC, since it's already nonstandard functionality? I tested it and it seemed to work, though I don't know how much testing I'd have to do to actually break it. (I'm hiding the call to __builtin_expect behind a macro, which is defined as a no-op for non-GCC, so it would be perfectly legal for other compilers.)

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  • The Red Gate and .NET Reflector Debacle

    - by Rick Strahl
    About a month ago Red Gate – the company who owns the NET Reflector tool most .NET devs use at one point or another – decided to change their business model for Reflector and take the product from free to a fully paid for license model. As a bit of history: .NET Reflector was originally created by Lutz Roeder as a free community tool to inspect .NET assemblies. Using Reflector you can examine the types in an assembly, drill into type signatures and quickly disassemble code to see how a particular method works.  In case you’ve been living under a rock and you’ve never looked at Reflector, here’s what it looks like drilled into an assembly from disk with some disassembled source code showing: Note that you get tons of information about each element in the tree, and almost all related types and members are clickable both in the list and source view so it’s extremely easy to navigate and follow the code flow even in this static assembly only view. For many year’s Lutz kept the the tool up to date and added more features gradually improving an already amazing tool and making it better. Then about two and a half years ago Red Gate bought the tool from Lutz. A lot of ruckus and noise ensued in the community back then about what would happen with the tool and… for the most part very little did. Other than the incessant update notices with prominent Red Gate promo on them life with Reflector went on. The product didn’t die and and it didn’t go commercial or to a charge model. When .NET 4.0 came out it still continued to work mostly because the .NET feature set doesn’t drastically change how types behave.  Then a month back Red Gate started making noise about a new Version Version 7 which would be commercial. No more free version - and a shit storm broke out in the community. Now normally I’m not one to be critical of companies trying to make money from a product, much less for a product that’s as incredibly useful as Reflector. There isn’t day in .NET development that goes by for me where I don’t fire up Reflector. Whether it’s for examining the innards of the .NET Framework, checking out third party code, or verifying some of my own code and resources. Even more so recently I’ve been doing a lot of Interop work with a non-.NET application that needs to access .NET components and Reflector has been immensely valuable to me (and my clients) if figuring out exact type signatures required to calling .NET components in assemblies. In short Reflector is an invaluable tool to me. Ok, so what’s the problem? Why all the fuss? Certainly the $39 Red Gate is trying to charge isn’t going to kill any developer. If there’s any tool in .NET that’s worth $39 it’s Reflector, right? Right, but that’s not the problem here. The problem is how Red Gate went about moving the product to commercial which borders on the downright bizarre. It’s almost as if somebody in management wrote a slogan: “How can we piss off the .NET community in the most painful way we can?” And that it seems Red Gate has a utterly succeeded. People are rabid, and for once I think that this outrage isn’t exactly misplaced. Take a look at the message thread that Red Gate dedicated from a link off the download page. Not only is Version 7 going to be a paid commercial tool, but the older versions of Reflector won’t be available any longer. Not only that but older versions that are already in use also will continually try to update themselves to the new paid version – which when installed will then expire unless registered properly. There have also been reports of Version 6 installs shutting themselves down and failing to work if the update is refused (I haven’t seen that myself so not sure if that’s true). In other words Red Gate is trying to make damn sure they’re getting your money if you attempt to use Reflector. There’s a lot of temptation there. Think about the millions of .NET developers out there and all of them possibly upgrading – that’s a nice chunk of change that Red Gate’s sitting on. Even with all the community backlash these guys are probably making some bank right now just because people need to get life to move on. Red Gate also put up a Feedback link on the download page – which not surprisingly is chock full with hate mail condemning the move. Oddly there’s not a single response to any of those messages by the Red Gate folks except when it concerns license questions for the full version. It puzzles me what that link serves for other yet than another complete example of failure to understand how to handle customer relations. There’s no doubt that that all of this has caused some serious outrage in the community. The sad part though is that this could have been handled so much less arrogantly and without pissing off the entire community and causing so much ill-will. People are pissed off and I have no doubt that this negative publicity will show up in the sales numbers for their other products. I certainly hope so. Stupidity ought to be painful! Why do Companies do boneheaded stuff like this? Red Gate’s original decision to buy Reflector was hotly debated but at that the time most of what would happen was mostly speculation. But I thought it was a smart move for any company that is in need of spreading its marketing message and corporate image as a vendor in the .NET space. Where else do you get to flash your corporate logo to hordes of .NET developers on a regular basis?  Exploiting that marketing with some goodwill of providing a free tool breeds positive feedback that hopefully has a good effect on the company’s visibility and the products it sells. Instead Red Gate seems to have taken exactly the opposite tack of corporate bullying to try to make a quick buck – and in the process ruined any community goodwill that might have come from providing a service community for free while still getting valuable marketing. What’s so puzzling about this boneheaded escapade is that the company doesn’t need to resort to underhanded tactics like what they are trying with Reflector 7. The tools the company makes are very good. I personally use SQL Compare, Sql Data Compare and ANTS Profiler on a regular basis and all of these tools are essential in my toolbox. They certainly work much better than the tools that are in the box with Visual Studio. Chances are that if Reflector 7 added useful features I would have been more than happy to shell out my $39 to upgrade when the time is right. It’s Expensive to give away stuff for Free At the same time, this episode shows some of the big problems that come with ‘free’ tools. A lot of organizations are realizing that giving stuff away for free is actually quite expensive and the pay back is often very intangible if any at all. Those that rely on donations or other voluntary compensation find that they amount contributed is absolutely miniscule as to not matter at all. Yet at the same time I bet most of those clamouring the loudest on that Red Gate Reflector feedback page that Reflector won’t be free anymore probably have NEVER made a donation to any open source project or free tool ever. The expectation of Free these days is just too great – which is a shame I think. There’s a lot to be said for paid software and having somebody to hold to responsible to because you gave them some money. There’s an incentive –> payback –> responsibility model that seems to be missing from free software (not all of it, but a lot of it). While there certainly are plenty of bad apples in paid software as well, money tends to be a good motivator for people to continue working and improving products. Reasons for giving away stuff are many but often it’s a naïve desire to share things when things are simple. At first it might be no problem to volunteer time and effort but as products mature the fun goes out of it, and as the reality of product maintenance kicks in developers want to get something back for the time and effort they’re putting in doing non-glamorous work. It’s then when products die or languish and this is painful for all to watch. For Red Gate however, I think there was always a pretty good payback from the Reflector acquisition in terms of marketing: Visibility and possible positioning of their products although they seemed to have mostly ignored that option. On the other hand they started this off pretty badly even 2 and a half years back when they aquired Reflector from Lutz with the same arrogant attitude that is evident in the latest episode. You really gotta wonder what folks are thinking in management – the sad part is from advance emails that were circulating, they were fully aware of the shit storm they were inciting with this and I suspect they are banking on the sheer numbers of .NET developers to still make them a tidy chunk of change from upgrades… Alternatives are coming For me personally the single license isn’t a problem, but I actually have a tool that I sell (an interop Web Service proxy generation tool) to customers and one of the things I recommend to use with has been Reflector to view assembly information and to find which Interop classes to instantiate from the non-.NET environment. It’s been nice to use Reflector for this with its small footprint and zero-configuration installation. But now with V7 becoming a paid tool that option is not going to be available anymore. Luckily it looks like the .NET community is jumping to it and trying to fill the void. Amidst the Red Gate outrage a new library called ILSpy has sprung up and providing at least some of the core functionality of Reflector with an open source library. It looks promising going forward and I suspect there will be a lot more support and interest to support this project now that Reflector has gone over to the ‘dark side’…© Rick Strahl, West Wind Technologies, 2005-2011

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  • A New Threat To Web Applications: Connection String Parameter Pollution (CSPP)

    - by eric.maurice
    Hi, this is Shaomin Wang. I am a security analyst in Oracle's Security Alerts Group. My primary responsibility is to evaluate the security vulnerabilities reported externally by security researchers on Oracle Fusion Middleware and to ensure timely resolution through the Critical Patch Update. Today, I am going to talk about a serious type of attack: Connection String Parameter Pollution (CSPP). Earlier this year, at the Black Hat DC 2010 Conference, two Spanish security researchers, Jose Palazon and Chema Alonso, unveiled a new class of security vulnerabilities, which target insecure dynamic connections between web applications and databases. The attack called Connection String Parameter Pollution (CSPP) exploits specifically the semicolon delimited database connection strings that are constructed dynamically based on the user inputs from web applications. CSPP, if carried out successfully, can be used to steal user identities and hijack web credentials. CSPP is a high risk attack because of the relative ease with which it can be carried out (low access complexity) and the potential results it can have (high impact). In today's blog, we are going to first look at what connection strings are and then review the different ways connection string injections can be leveraged by malicious hackers. We will then discuss how CSPP differs from traditional connection string injection, and the measures organizations can take to prevent this kind of attacks. In web applications, a connection string is a set of values that specifies information to connect to backend data repositories, in most cases, databases. The connection string is passed to a provider or driver to initiate a connection. Vendors or manufacturers write their own providers for different databases. Since there are many different providers and each provider has multiple ways to make a connection, there are many different ways to write a connection string. Here are some examples of connection strings from Oracle Data Provider for .Net/ODP.Net: Oracle Data Provider for .Net / ODP.Net; Manufacturer: Oracle; Type: .NET Framework Class Library: - Using TNS Data Source = orcl; User ID = myUsername; Password = myPassword; - Using integrated security Data Source = orcl; Integrated Security = SSPI; - Using the Easy Connect Naming Method Data Source = username/password@//myserver:1521/my.server.com - Specifying Pooling parameters Data Source=myOracleDB; User Id=myUsername; Password=myPassword; Min Pool Size=10; Connection Lifetime=120; Connection Timeout=60; Incr Pool Size=5; Decr Pool Size=2; There are many variations of the connection strings, but the majority of connection strings are key value pairs delimited by semicolons. Attacks on connection strings are not new (see for example, this SANS White Paper on Securing SQL Connection String). Connection strings are vulnerable to injection attacks when dynamic string concatenation is used to build connection strings based on user input. When the user input is not validated or filtered, and malicious text or characters are not properly escaped, an attacker can potentially access sensitive data or resources. For a number of years now, vendors, including Oracle, have created connection string builder class tools to help developers generate valid connection strings and potentially prevent this kind of vulnerability. Unfortunately, not all application developers use these utilities because they are not aware of the danger posed by this kind of attacks. So how are Connection String parameter Pollution (CSPP) attacks different from traditional Connection String Injection attacks? First, let's look at what parameter pollution attacks are. Parameter pollution is a technique, which typically involves appending repeating parameters to the request strings to attack the receiving end. Much of the public attention around parameter pollution was initiated as a result of a presentation on HTTP Parameter Pollution attacks by Stefano Di Paola and Luca Carettoni delivered at the 2009 Appsec OWASP Conference in Poland. In HTTP Parameter Pollution attacks, an attacker submits additional parameters in HTTP GET/POST to a web application, and if these parameters have the same name as an existing parameter, the web application may react in different ways depends on how the web application and web server deal with multiple parameters with the same name. When applied to connections strings, the rule for the majority of database providers is the "last one wins" algorithm. If a KEYWORD=VALUE pair occurs more than once in the connection string, the value associated with the LAST occurrence is used. This opens the door to some serious attacks. By way of example, in a web application, a user enters username and password; a subsequent connection string is generated to connect to the back end database. Data Source = myDataSource; Initial Catalog = db; Integrated Security = no; User ID = myUsername; Password = XXX; In the password field, if the attacker enters "xxx; Integrated Security = true", the connection string becomes, Data Source = myDataSource; Initial Catalog = db; Integrated Security = no; User ID = myUsername; Password = XXX; Intergrated Security = true; Under the "last one wins" principle, the web application will then try to connect to the database using the operating system account under which the application is running to bypass normal authentication. CSPP poses serious risks for unprepared organizations. It can be particularly dangerous if an Enterprise Systems Management web front-end is compromised, because attackers can then gain access to control panels to configure databases, systems accounts, etc. Fortunately, organizations can take steps to prevent this kind of attacks. CSPP falls into the Injection category of attacks like Cross Site Scripting or SQL Injection, which are made possible when inputs from users are not properly escaped or sanitized. Escaping is a technique used to ensure that characters (mostly from user inputs) are treated as data, not as characters, that is relevant to the interpreter's parser. Software developers need to become aware of the danger of these attacks and learn about the defenses mechanism they need to introduce in their code. As well, software vendors need to provide templates or classes to facilitate coding and eliminate developers' guesswork for protecting against such vulnerabilities. Oracle has introduced the OracleConnectionStringBuilder class in Oracle Data Provider for .NET. Using this class, developers can employ a configuration file to provide the connection string and/or dynamically set the values through key/value pairs. It makes creating connection strings less error-prone and easier to manager, and ultimately using the OracleConnectionStringBuilder class provides better security against injection into connection strings. For More Information: - The OracleConnectionStringBuilder is located at http://download.oracle.com/docs/cd/B28359_01/win.111/b28375/OracleConnectionStringBuilderClass.htm - Oracle has developed a publicly available course on preventing SQL Injections. The Server Technologies Curriculum course "Defending Against SQL Injection Attacks!" is located at http://st-curriculum.oracle.com/tutorial/SQLInjection/index.htm - The OWASP web site also provides a number of useful resources. It is located at http://www.owasp.org/index.php/Main_Page

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  • Java Cloud Service Integration using Web Service Data Control

    - by Jani Rautiainen
    Java Cloud Service (JCS) provides a platform to develop and deploy business applications in the cloud. In Fusion Applications Cloud deployments customers do not have the option to deploy custom applications developed with JDeveloper to ensure the integrity and supportability of the hosted application service. Instead the custom applications can be deployed to the JCS and integrated to the Fusion Application Cloud instance.This series of articles will go through the features of JCS, provide end-to-end examples on how to develop and deploy applications on JCS and how to integrate them with the Fusion Applications instance.In this article a custom application integrating with Fusion Application using Web Service Data Control will be implemented. v\:* {behavior:url(#default#VML);} o\:* {behavior:url(#default#VML);} w\:* {behavior:url(#default#VML);} .shape {behavior:url(#default#VML);} 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:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:"Calibri","sans-serif";} Pre-requisites Access to Cloud instance In order to deploy the application access to a JCS instance is needed, a free trial JCS instance can be obtained from Oracle Cloud site. To register you will need a credit card even if the credit card will not be charged. To register simply click "Try it" and choose the "Java" option. The confirmation email will contain the connection details. See this video for example of the registration. Once the request is processed you will be assigned 2 service instances; Java and Database. Applications deployed to the JCS must use Oracle Database Cloud Service as their underlying database. So when JCS instance is created a database instance is associated with it using a JDBC data source. The cloud services can be monitored and managed through the web UI. For details refer to Getting Started with Oracle Cloud. JDeveloper JDeveloper contains Cloud specific features related to e.g. connection and deployment. To use these features download the JDeveloper from JDeveloper download site by clicking the “Download JDeveloper 11.1.1.7.1 for ADF deployment on Oracle Cloud” link, this version of JDeveloper will have the JCS integration features that will be used in this article. For versions that do not include the Cloud integration features the Oracle Java Cloud Service SDK or the JCS Java Console can be used for deployment. For details on installing and configuring the JDeveloper refer to the installation guide. For details on SDK refer to Using the Command-Line Interface to Monitor Oracle Java Cloud Service and Using the Command-Line Interface to Manage Oracle Java Cloud Service. Create Application In this example the “JcsWsDemo” application created in the “Java Cloud Service Integration using Web Service Proxy” article is used as the base. Create Web Service Data Control In this example we will use a Web Service Data Control to integrate with Credit Rule Service in Fusion Applications. The data control will be used to query data from Fusion Applications using a web service call and present the data in a table. To generate the data control choose the “Model” project and navigate to "New -> All Technologies -> Business Tier -> Data Controls -> Web Service Data Control" and enter following: Name: CreditRuleServiceDC URL: https://ic-[POD].oracleoutsourcing.com/icCnSetupCreditRulesPublicService/CreditRuleService?WSDL Service: {{http://xmlns.oracle.com/apps/incentiveCompensation/cn/creditSetup/creditRule/creditRuleService/}CreditRuleService On step 2 select the “findRule” operation: Skip step 3 and on step 4 define the credentials to access the service. Do note that in this example these credentials are only used if testing locally, for JCS deployment credentials need to be manually updated on the EAR file: Click “Finish” and the proxy generation is done. Creating UI In order to use the data control we will need to populate complex objects FindCriteria and FindControl. For simplicity in this example we will create logic in a managed bean that populates the objects. Open “JcsWsDemoBean.java” and add the following logic: Map findCriteria; Map findControl; public void setFindCriteria(Map findCriteria) { this.findCriteria = findCriteria; } public Map getFindCriteria() { findCriteria = new HashMap(); findCriteria.put("fetchSize",10); findCriteria.put("fetchStart",0); return findCriteria; } public void setFindControl(Map findControl) { this.findControl = findControl; } public Map getFindControl() { findControl = new HashMap(); return findControl; } Open “JcsWsDemo.jspx”, navigate to “Data Controls -> CreditRuleServiceDC -> findRule(Object, Object) -> result” and drag and drop the “result” node into the “af:form” element in the page: On the “Edit Table Columns” remove all columns except “RuleId” and “Name”: On the “Edit Action Binding” window displayed enter reference to the java class created above by selecting “#{JcsWsDemoBean.findCriteria}”: Also define the value for the “findControl” by selecting “#{JcsWsDemoBean.findControl}”. Deploy to JCS For WS DC the authentication details need to be updated on the connection details before deploying. Open “connections.xml” by navigating “Application Resources -> Descriptors -> ADF META-INF -> connections.xml”: Change the user name and password entry from: <soap username="transportUserName" password="transportPassword" To match the access details for the target environment. Follow the same steps as documented in previous article ”Java Cloud Service ADF Web Application”. Once deployed the application can be accessed with URL: https://java-[identity domain].java.[data center].oraclecloudapps.com/JcsWsDemo-ViewController-context-root/faces/JcsWsDemo.jspx When accessed the first 10 rules in the system are displayed: Summary In this article we learned how to integrate with Fusion Applications using a Web Service Data Control in JCS. In future articles various other integration techniques will be covered. 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:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:"Calibri","sans-serif";}

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  • MySQL Cluster 7.3 Labs Release – Foreign Keys Are In!

    - by Mat Keep
    0 0 1 1097 6254 Homework 52 14 7337 14.0 Normal 0 false false false EN-US JA X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:12.0pt; font-family:Cambria; mso-ascii-font-family:Cambria; mso-ascii-theme-font:minor-latin; mso-hansi-font-family:Cambria; mso-hansi-theme-font:minor-latin; mso-ansi-language:EN-US;} Summary (aka TL/DR): Support for Foreign Key constraints has been one of the most requested feature enhancements for MySQL Cluster. We are therefore extremely excited to announce that Foreign Keys are part of the first Labs Release of MySQL Cluster 7.3 – available for download, evaluation and feedback now! (Select the mysql-cluster-7.3-labs-June-2012 build) In this blog, I will attempt to discuss the design rationale, implementation, configuration and steps to get started in evaluating the first MySQL Cluster 7.3 Labs Release. Pace of Innovation It was only a couple of months ago that we announced the General Availability (GA) of MySQL Cluster 7.2, delivering 1 billion Queries per Minute, with 70x higher cross-shard JOIN performance, Memcached NoSQL key-value API and cross-data center replication.  This release has been a huge hit, with downloads and deployments quickly reaching record levels. The announcement of the first MySQL Cluster 7.3 Early Access lab release at today's MySQL Innovation Day event demonstrates the continued pace in Cluster development, and provides an opportunity for the community to evaluate and feedback on new features they want to see. What’s the Plan for MySQL Cluster 7.3? Well, Foreign Keys, as you may have gathered by now (!), and this is the focus of this first Labs Release. As with MySQL Cluster 7.2, we plan to publish a series of preview releases for 7.3 that will incrementally add new candidate features for a final GA release (subject to usual safe harbor statement below*), including: - New NoSQL APIs; - Features to automate the configuration and provisioning of multi-node clusters, on premise or in the cloud; - Performance and scalability enhancements; - Taking advantage of features in the latest MySQL 5.x Server GA. Design Rationale MySQL Cluster is designed as a “Not-Only-SQL” database. It combines attributes that enable users to blend the best of both relational and NoSQL technologies into solutions that deliver web scalability with 99.999% availability and real-time performance, including: Concurrent NoSQL and SQL access to the database; Auto-sharding with simple scale-out across commodity hardware; Multi-master replication with failover and recovery both within and across data centers; Shared-nothing architecture with no single point of failure; Online scaling and schema changes; ACID compliance and support for complex queries, across shards. Native support for Foreign Key constraints enables users to extend the benefits of MySQL Cluster into a broader range of use-cases, including: - Packaged applications in areas such as eCommerce and Web Content Management that prescribe databases with Foreign Key support. - In-house developments benefiting from Foreign Key constraints to simplify data models and eliminate the additional application logic needed to maintain data consistency and integrity between tables. Implementation The Foreign Key functionality is implemented directly within MySQL Cluster’s data nodes, allowing any client API accessing the cluster to benefit from them – whether using SQL or one of the NoSQL interfaces (Memcached, C++, Java, JPA or HTTP/REST.) The core referential actions defined in the SQL:2003 standard are implemented: CASCADE RESTRICT NO ACTION SET NULL In addition, the MySQL Cluster implementation supports the online adding and dropping of Foreign Keys, ensuring the Cluster continues to serve both read and write requests during the operation. An important difference to note with the Foreign Key implementation in InnoDB is that MySQL Cluster does not support the updating of Primary Keys from within the Data Nodes themselves - instead the UPDATE is emulated with a DELETE followed by an INSERT operation. Therefore an UPDATE operation will return an error if the parent reference is using a Primary Key, unless using CASCADE action, in which case the delete operation will result in the corresponding rows in the child table being deleted. The Engineering team plans to change this behavior in a subsequent preview release. Also note that when using InnoDB "NO ACTION" is identical to "RESTRICT". In the case of MySQL Cluster “NO ACTION” means “deferred check”, i.e. the constraint is checked before commit, allowing user-defined triggers to automatically make changes in order to satisfy the Foreign Key constraints. Configuration There is nothing special you have to do here – Foreign Key constraint checking is enabled by default. If you intend to migrate existing tables from another database or storage engine, for example from InnoDB, there are a couple of best practices to observe: 1. Analyze the structure of the Foreign Key graph and run the ALTER TABLE ENGINE=NDB in the correct sequence to ensure constraints are enforced 2. Alternatively drop the Foreign Key constraints prior to the import process and then recreate when complete. Getting Started Read this blog for a demonstration of using Foreign Keys with MySQL Cluster.  You can download MySQL Cluster 7.3 Labs Release with Foreign Keys today - (select the mysql-cluster-7.3-labs-June-2012 build) If you are new to MySQL Cluster, the Getting Started guide will walk you through installing an evaluation cluster on a singe host (these guides reflect MySQL Cluster 7.2, but apply equally well to 7.3) Post any questions to the MySQL Cluster forum where our Engineering team will attempt to assist you. Post any bugs you find to the MySQL bug tracking system (select MySQL Cluster from the Category drop-down menu) And if you have any feedback, please post them to the Comments section of this blog. Summary MySQL Cluster 7.2 is the GA, production-ready release of MySQL Cluster. This first Labs Release of MySQL Cluster 7.3 gives you the opportunity to preview and evaluate future developments in the MySQL Cluster database, and we are very excited to be able to share that with you. Let us know how you get along with MySQL Cluster 7.3, and other features that you want to see in future releases. * Safe Harbor Statement This information is intended to outline our general product direction. It is intended for information purposes only, and may not be incorporated into any contract. It is not a commitment to deliver any material, code, or functionality, and should not be relied upon in making purchasing decisions. The development, release, and timing of any features or functionality described for Oracle’s products remains at the sole discretion of Oracle.

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  • Entity LINQ on many-to-many got error "LINQ to Entities does not recognize the method 'Boolean Conta

    - by user300992
    I have 2 tables (Users and Roles) they are mapped as Many-to-Many in relational db. When I imported to Entity Data Content, they are still staying as the same relationship. Since they are mapped as Many-To-Many in Entity, I can access Users.RoleCollection or Roles.UserCollection However, when I execute this LINQ query, I got "LINQ to Entities does not recognize the method 'Boolean Contains... method, and this method cannot be translated into a store expression." var result (from a in Users from b in Roles where a.RoleCollection.Contains(b) select a); I think I must did something wrong... please help.

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