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  • Advanced Data Source Engine coming to Telerik Reporting Q1 2010

    This is the final blog post from the pre-release series. In it we are going to share with you some of the updates coming to our reporting solution in Q1 2010. A new Declarative Data Source Engine will be added to Telerik Reporting, that will allow full control over data management, and deliver significant gains in rendering performance and memory consumption. Some of the engines new features will be: Data source parameters - those parameters will be used to limit data retrieved from the data source to just the data needed for the report. Data source parameters are processed on the data source side, however only queried data is fetched to the reporting engine, rather than the full data source. This leads to lower memory consumption, because data operations are performed on queried data only, rather than on all data. As a result, only the queried data needs to be stored in the memory vs. the whole dataset, which was the case with the old approach Support for stored procedures - they will assist in achieving a consistent implementation of logic across applications, and are especially practical for performing repetitive tasks. A stored procedure stores the SQL statements and logic, which can then be executed in different reports and/or applications. Stored Procedures will not only save development time, but they will also improve performance, because each stored procedure is compiled on the data base server once, and then is reutilized. In Telerik Reporting, the stored procedure will also be parameterized, where elements of the SQL statement will be bound to parameters. These parameterized SQL queries will be handled through the data source parameters, and are evaluated at run time. Using parameterized SQL queries will improve the performance and decrease the memory footprint of your application, because they will be applied directly on the database server and only the necessary data will be downloaded on the middle tier or client machine; Calculated fields through expressions - with the help of the new reporting engine you will be able to use field values in formulas to come up with a calculated field. A calculated field is a user defined field that is computed "on the fly" and does not exist in the data source, but can perform calculations using the data of the data source object it belongs to. Calculated fields are very handy for adding frequently used formulas to your reports; Improved performance and optimized in-memory OLAP engine - the new data source will come with several improvements in how aggregates are calculated, and memory is managed. As a result, you may experience between 30% (for simpler reports) and 400% (for calculation-intensive reports) in rendering performance, and about 50% decrease in memory consumption. Full design time support through wizards - Declarative data sources are a great advance and will save developers countless hours of coding. In Q1 2010, and true to Telerik Reportings essence, using the new data source engine and its features requires little to no coding, because we have extended most of the wizards to support the new functionality. The newly extended wizards are available in VS2005/VS2008/VS2010 design-time. More features will be revealed on the product's what's new page when the new version is officially released in a few days. Also make sure you attend the free webinar on Thursday, March 11th that will be dedicated to the updates in Telerik Reporting Q1 2010. Did you know that DotNetSlackers also publishes .net articles written by top known .net Authors? We already have over 80 articles in several categories including Silverlight. Take a look: here.

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  • Screen Scraping Twitter

    - by BRADINO
    I got an email today asking for help to scrape Twitter. In particular, to be able to login. So I am going to show everyone, NOT to encourage anyone to violate Twitters terms of use but as an educational blog post about how PHP and cURL can be used to post variables and store cookies. Again, I am using the cScrape class I wrote, which you can download. Step 1 First go to twitter.com and look at the source code of the login to get the form field names and the form post location. You will see that the form posts to https://twitter.com/session and the username and password fields are session[username_or_email] and session[password] respectively. Step 2 Now you are ready to login. So using the fetch function in the Scrape class you create an associative array to contain the form values you want to post. The other thing you will need to do is uncomment the lines for CURLOPT_COOKIEFILE and CURLOPT_COOKIEJAR. Cookies will be required to stay logged in and scrape around. The paths to the cookie files need to be writable by your app. Also you will need to uncomment the line about CURLOPT_FOLLOWLOCATION. $data = array('session[username_or_email]' => "bradino", 'session[password]' => "secret"); $scrape->fetch('https://twitter.com/sessions',$data); Step 1.5 Oops that didn't work. All I got back was 403 Forbidden: The server understood the request, but is refusing to fulfill it. Ahhh I see another variable called authenticity_token I bet Twitter was looking for that. So let's back up and first hit twitter.com to get the authenticity_token variable, and then make the login post request with that variable included in our array of parameters. $scrape->fetch('https://twitter.com'); $data = array('session[username_or_email]' => "bradino", 'session[password]' => "secret"); $data['authenticity_token'] = $scrape->fetchBetween('name="authenticity_token" type="hidden" value="','"',$scrape->result); $scrape->fetch('https://twitter.com/sessions',$data); echo $scrape->result; So that's basically it. Now you are logged in and can scrape around and request other pages as you normally would. Sorry it wasn't a longer post. I really do enjoy this kind of stuff so if anyone has a request, hit me up. Errors? 1) Make sure that you are properly parsing the token variable 2) Make sure that you uncommented the lines about CURLOPT_COOKIEFILE and CURLOPT_COOKIEJAR, those options need to be enabled and be sure the path set is writable by your application 3) Make sure that the path to the cookie file is writable and that it is getting data written to it 4) If you get a message about being redirected you need to uncomment the line about CURLOPT_FOLLOWLOCATION, that option needs to be enabled true

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  • Automating XNA Performance Testing?

    - by Grofit
    I was wondering what peoples approaches or thoughts were on automating performance testing in XNA. Currently I am looking at only working in 2d, but that poses many areas where performance can be improved with different implementations. An example would be if you had 2 different implementations of spatial partitioning, one may be faster than another but without doing some actual performance testing you wouldn't be able to tell which one for sure (unless you saw the code was blatantly slow in certain parts). You could write a unit test which for a given time frame kept adding/updating/removing entities for both implementations and see how many were made in each timeframe and the higher one would be the faster one (in this given example). Another higher level example would be if you wanted to see how many entities you can have on the screen roughly without going beneath 60fps. The problem with this is to automate it you would need to use the hidden form trick or some other thing to kick off a mock game and purely test which parts you care about and disable everything else. I know that this isnt a simple affair really as even if you can automate the tests, really it is up to a human to interpret if the results are performant enough, but as part of a build step you could have it run these tests and publish the results somewhere for comparison. This way if you go from version 1.1 to 1.2 but have changed a few underlying algorithms you may notice that generally the performance score would have gone up, meaning you have improved your overall performance of the application, and then from 1.2 to 1.3 you may notice that you have then dropped overall performance a bit. So has anyone automated this sort of thing in their projects, and if so how do you measure your performance comparisons at a high level and what frameworks do you use to test? As providing you have written your code so its testable/mockable for most parts you can just use your tests as a mechanism for getting some performance results... === Edit === Just for clarity, I am more interested in the best way to make use of automated tests within XNA to track your performance, not play testing or guessing by manually running your game on a machine. This is completely different to seeing if your game is playable on X hardware, it is more about tracking the change in performance as your game engine/framework changes. As mentioned in one of the comments you could easily test "how many nodes can I insert/remove/update within QuadTreeA within 2 seconds", but you have to physically look at these results every time to see if it has changed, which may be fine and is still better than just relying on playing it to see if you notice any difference between version. However if you were to put an Assert in to notify you of a fail if it goes lower than lets say 5000 in 2 seconds you have a brittle test as it is then contextual to the hardware, not just the implementation. Although that being said these sort of automated tests are only really any use if you are running your tests as some sort of build pipeline i.e: Checkout - Run Unit Tests - Run Integration Tests - Run Performance Tests - Package So then you can easily compare the stats from one build to another on the CI server as a report of some sort, and again this may not mean much to anyone if you are not used to Continuous Integration. The main crux of this question is to see how people manage this between builds and how they find it best to report upon. As I said it can be subjective but as knowledge will be gained from the answers it seems a worthwhile question.

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  • Big Data – Buzz Words: What is MapReduce – Day 7 of 21

    - by Pinal Dave
    In yesterday’s blog post we learned what is Hadoop. In this article we will take a quick look at one of the four most important buzz words which goes around Big Data – MapReduce. What is MapReduce? MapReduce was designed by Google as a programming model for processing large data sets with a parallel, distributed algorithm on a cluster. Though, MapReduce was originally Google proprietary technology, it has been quite a generalized term in the recent time. MapReduce comprises a Map() and Reduce() procedures. Procedure Map() performance filtering and sorting operation on data where as procedure Reduce() performs a summary operation of the data. This model is based on modified concepts of the map and reduce functions commonly available in functional programing. The library where procedure Map() and Reduce() belongs is written in many different languages. The most popular free implementation of MapReduce is Apache Hadoop which we will explore tomorrow. Advantages of MapReduce Procedures The MapReduce Framework usually contains distributed servers and it runs various tasks in parallel to each other. There are various components which manages the communications between various nodes of the data and provides the high availability and fault tolerance. Programs written in MapReduce functional styles are automatically parallelized and executed on commodity machines. The MapReduce Framework takes care of the details of partitioning the data and executing the processes on distributed server on run time. During this process if there is any disaster the framework provides high availability and other available modes take care of the responsibility of the failed node. As you can clearly see more this entire MapReduce Frameworks provides much more than just Map() and Reduce() procedures; it provides scalability and fault tolerance as well. A typical implementation of the MapReduce Framework processes many petabytes of data and thousands of the processing machines. How do MapReduce Framework Works? A typical MapReduce Framework contains petabytes of the data and thousands of the nodes. Here is the basic explanation of the MapReduce Procedures which uses this massive commodity of the servers. Map() Procedure There is always a master node in this infrastructure which takes an input. Right after taking input master node divides it into smaller sub-inputs or sub-problems. These sub-problems are distributed to worker nodes. A worker node later processes them and does necessary analysis. Once the worker node completes the process with this sub-problem it returns it back to master node. Reduce() Procedure All the worker nodes return the answer to the sub-problem assigned to them to master node. The master node collects the answer and once again aggregate that in the form of the answer to the original big problem which was assigned master node. The MapReduce Framework does the above Map () and Reduce () procedure in the parallel and independent to each other. All the Map() procedures can run parallel to each other and once each worker node had completed their task they can send it back to master code to compile it with a single answer. This particular procedure can be very effective when it is implemented on a very large amount of data (Big Data). The MapReduce Framework has five different steps: Preparing Map() Input Executing User Provided Map() Code Shuffle Map Output to Reduce Processor Executing User Provided Reduce Code Producing the Final Output Here is the Dataflow of MapReduce Framework: Input Reader Map Function Partition Function Compare Function Reduce Function Output Writer In a future blog post of this 31 day series we will explore various components of MapReduce in Detail. MapReduce in a Single Statement MapReduce is equivalent to SELECT and GROUP BY of a relational database for a very large database. Tomorrow In tomorrow’s blog post we will discuss Buzz Word – HDFS. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: Big Data, PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL

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  • Ubuntu 10.04 & IBM DS3524 with FC multipath, inactive path is [failed][faulty] instead of [active][ghost]

    - by Graeme Donaldson
    OK, this is my setup: FC Switches IBM/Brocade, Switch1 and Switch2, independent fabrics. Server IBM x3650 M2, 2x QLogic QLE2460, 1 connected to each FC Switch. Storage IBM DS3524, 2x controllers with 4x FC ports each, but only 2x connected on each. +-----------------------------------------------------------------------+ | HBA1 Server HBA2 | +-----------------------------------------------------------------------+ | | | | | | +-----------------------------+ +------------------------------+ | Switch1 | | Switch2 | +-----------------------------+ +------------------------------+ | | | | | | | | | | | | | | | | | | | | +-----------------------------------+-----------------------------------+ | Contr A, port 3 | Contr A, port 4 | Contr B, port 3 | Contr B, port 4 | +-----------------------------------+-----------------------------------+ | Storage | +-----------------------------------------------------------------------+ My /etc/multipath.conf is from the IBM redbook for the DS3500, except I use a different setting for prio_callout, IBM uses /sbin/mpath_prio_tpc, but according to http://changelogs.ubuntu.com/changelogs/pool/main/m/multipath-tools/multipath-tools_0.4.8-7ubuntu2/changelog, this was renamed to /sbin/mpath_prio_rdac, which I'm using. devices { device { #ds3500 vendor "IBM" product "1746 FAStT" hardware_handler "1 rdac" path_checker rdac failback 0 path_grouping_policy multibus prio_callout "/sbin/mpath_prio_rdac /dev/%n" } } multipaths { multipath { wwid xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx alias array07 path_grouping_policy multibus path_checker readsector0 path_selector "round-robin 0" failback "5" rr_weight priorities no_path_retry "5" } } The output of multipath -ll with controller A as the preferred path: root@db06:~# multipath -ll sdg: checker msg is "directio checker reports path is down" sdh: checker msg is "directio checker reports path is down" array07 (xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx) dm-2 IBM ,1746 FASt [size=4.9T][features=1 queue_if_no_path][hwhandler=0] \_ round-robin 0 [prio=2][active] \_ 5:0:1:0 sdd 8:48 [active][ready] \_ 5:0:2:0 sde 8:64 [active][ready] \_ 6:0:1:0 sdg 8:96 [failed][faulty] \_ 6:0:2:0 sdh 8:112 [failed][faulty] If I change the preferred path using IBM DS Storage Manager to Controller B, the output swaps accordingly: root@db06:~# multipath -ll sdd: checker msg is "directio checker reports path is down" sde: checker msg is "directio checker reports path is down" array07 (xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx) dm-2 IBM ,1746 FASt [size=4.9T][features=1 queue_if_no_path][hwhandler=0] \_ round-robin 0 [prio=2][active] \_ 5:0:1:0 sdd 8:48 [failed][faulty] \_ 5:0:2:0 sde 8:64 [failed][faulty] \_ 6:0:1:0 sdg 8:96 [active][ready] \_ 6:0:2:0 sdh 8:112 [active][ready] According to IBM, the inactive path should be "[active][ghost]", not "[failed][faulty]". Despite this, I don't seem to have any I/O issues, but my syslog is being spammed with this every 5 seconds: Jun 1 15:30:09 db06 multipathd: sdg: directio checker reports path is down Jun 1 15:30:09 db06 kernel: [ 2350.282065] sd 6:0:2:0: [sdh] Result: hostbyte=DID_OK driverbyte=DRIVER_SENSE Jun 1 15:30:09 db06 kernel: [ 2350.282071] sd 6:0:2:0: [sdh] Sense Key : Illegal Request [current] Jun 1 15:30:09 db06 kernel: [ 2350.282076] sd 6:0:2:0: [sdh] <<vendor>> ASC=0x94 ASCQ=0x1ASC=0x94 ASCQ=0x1 Jun 1 15:30:09 db06 kernel: [ 2350.282083] sd 6:0:2:0: [sdh] CDB: Read(10): 28 00 00 00 00 00 00 00 08 00 Jun 1 15:30:09 db06 kernel: [ 2350.282092] end_request: I/O error, dev sdh, sector 0 Jun 1 15:30:10 db06 multipathd: sdh: directio checker reports path is down Jun 1 15:30:14 db06 kernel: [ 2355.312270] sd 6:0:1:0: [sdg] Result: hostbyte=DID_OK driverbyte=DRIVER_SENSE Jun 1 15:30:14 db06 kernel: [ 2355.312277] sd 6:0:1:0: [sdg] Sense Key : Illegal Request [current] Jun 1 15:30:14 db06 kernel: [ 2355.312282] sd 6:0:1:0: [sdg] <<vendor>> ASC=0x94 ASCQ=0x1ASC=0x94 ASCQ=0x1 Jun 1 15:30:14 db06 kernel: [ 2355.312290] sd 6:0:1:0: [sdg] CDB: Read(10): 28 00 00 00 00 00 00 00 08 00 Jun 1 15:30:14 db06 kernel: [ 2355.312299] end_request: I/O error, dev sdg, sector 0 Does anyone know how I can get the inactive path to show "[active][ghost]" instead of "[failed][faulty]"? I assume that once I can get that right then the spam in my syslog will end as well. One final thing worth mentioning is that the IBM redbook doc targets SLES 11 so I'm assuming there's something a little different under Ubuntu that I just haven't figured out yet. Update: As suggested by Mitch, I've tried removing /etc/multipath.conf, and now the output of multipath -ll looks like this: root@db06:~# multipath -ll sdg: checker msg is "directio checker reports path is down" sdh: checker msg is "directio checker reports path is down" xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxdm-1 IBM ,1746 FASt [size=4.9T][features=0][hwhandler=0] \_ round-robin 0 [prio=1][active] \_ 5:0:2:0 sde 8:64 [active][ready] \_ round-robin 0 [prio=1][enabled] \_ 5:0:1:0 sdd 8:48 [active][ready] \_ round-robin 0 [prio=0][enabled] \_ 6:0:1:0 sdg 8:96 [failed][faulty] \_ round-robin 0 [prio=0][enabled] \_ 6:0:2:0 sdh 8:112 [failed][faulty] So its more or less the same, with the same message in the syslog every 5 minutes as before, but the grouping has changed.

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  • Web Services for Info Explorer Zones

    - by Anthony Shorten
    One of the most interesting uses for XAI and Configurable objects is the exposure of a query portal as a Web Service. Let me illustrate this with an example. Say you have an interface that requires a list of data from a number of product tables. In the past you would have to build a java program to do this with SQL then use an application service but it is now possible with just configuration. The first step in the process is to create the SQL you want to use for the interface. It can be any valid static SQL or use host variables for the WHERE clause (we call that filtered). Once you are happy with the SQL (and it performs acceptably) you can incorporate that SQL into a Info-Explorer Zone. You can use any of the explorer zone types but I typically recommend F1-DE-SINGLE as it supports a single SQL statement with multiple filters (up to 15) as well as hidden filters (up to 5). Hidden filters are typically not displayed in the UI for criteria (remember explorer zones can be used on the user Interface as well) but for web services they can be used as normal filters (this means you can use up to 20 filters all up). Once you are happy with the zone, you now need to define it as a Business Service. We have a generic service called FWLZDEXP which allows a explorer zone to be defined as a Business Service. If you open any Business Service based upon FWLZDEXP you will see some examples. The schema is standard and pretty self explanatory in terms of the structure. The schema pattern looks like this: Zone element - maps to the ZONE_CD element and the default value is the zone name you just created. This links the business service to the zone. Filter elements - You name the filters as you like but the mapField is set to Fx_VALUE where x is the filter number corresponding to the filter element in the zone definition. Hidden filter elements - You name the filters as you like but the mapField is set to Hx_VALUE where x is the filter number corresponding to the hidden filter element in the zone definition. results group - this holds the elements of the result set. Each element in your result set has a tagname and is linked to the COL_VALUE mapField and the row element is lists the SEQNO of the column. This corresponds to the column number in the results set in the zone. An example schema is shown below for the F1-USGRACML zone, which returns the access modes for a user group and application service filters. In the example, the userGroup and applicationService elements are the filters and the rows would contain a list of accessModeDescr. This is just a simple example to illustrate the point. There are lots of examples in the product that you can investigate. One recommendation, to save time, is that you copy the schema from one of the examples to save you typing it from scratch. You can simply modify the tags and other elements to suit your needs. Once the Business Service is defined it can simply be defined as a Web Service by registering an XAI Inbound Service using the Business Service definition as a basis. You now have a Web Service based upon a Info Explorer Zone. This is one of my favorite components as it allows interfaces to be simplified. This will be my last blog entry for this year. I hope you all have a great and safe Christmas and an even greater new year. Next year promises to be an exciting year and I look forward to communicating exciting developments we are working on at the moment as they are released.

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  • How do you install a USB CD Rom drive?

    - by Matt Allen
    Hello, I recently purchased a USB CD ROM drive, but I don't know how to get it to work with my computer which runs Ubuntu 10.04. http://www.amazon.com/gp/product/B00303H908/ref=oss_product When I issue the lsusb command, it shows up as: Bus 002 Device 016: ID 05e3:0701 Genesys Logic, Inc. USB 2.0 IDE Adapter The computer doesn't recognize it automatically. How can I get this drive to show up as an actual drive on my computer? If this particular drive can't handle Linux, can you recommended one which can and provide a link to it so I can purchase it? Thanks! Update: I was asked by Scaine to run a command and report back with the output: joe@joe-laptop:~$ tail -f /var/log/kern.log Dec 29 12:51:35 joe-laptop kernel: [103190.551437] sr 7:0:0:0: [sr1] Add. Sense: Illegal mode for this track Dec 29 12:51:35 joe-laptop kernel: [103190.551446] sr 7:0:0:0: [sr1] CDB: Read(10): 28 00 00 00 00 00 00 00 02 00 Dec 29 12:51:35 joe-laptop kernel: [103190.551463] end_request: I/O error, dev sr1, sector 0 Dec 29 12:51:35 joe-laptop kernel: [103190.877542] sr 7:0:0:0: [sr1] Result: hostbyte=DID_OK driverbyte=DRIVER_SENSE Dec 29 12:51:35 joe-laptop kernel: [103190.877551] sr 7:0:0:0: [sr1] Sense Key : Illegal Request [current] Dec 29 12:51:35 joe-laptop kernel: [103190.877559] Info fld=0x0, ILI Dec 29 12:51:35 joe-laptop kernel: [103190.877562] sr 7:0:0:0: [sr1] Add. Sense: Illegal mode for this track Dec 29 12:51:35 joe-laptop kernel: [103190.877572] sr 7:0:0:0: [sr1] CDB: Read(10): 28 00 00 00 00 00 00 00 02 00 Dec 29 12:51:35 joe-laptop kernel: [103190.877588] end_request: I/O error, dev sr1, sector 0 Dec 29 13:08:46 joe-laptop kernel: [104221.558911] usb 2-2.2: USB disconnect, address 16 Then when I plugged the drive back into the computer, I got: Dec 29 13:10:29 joe-laptop kernel: [104324.668320] usb 2-2.2: new high speed USB device using ehci_hcd and address 17 Dec 29 13:10:29 joe-laptop kernel: [104324.761702] usb 2-2.2: configuration #1 chosen from 1 choice Dec 29 13:10:29 joe-laptop kernel: [104324.762700] scsi8 : SCSI emulation for USB Mass Storage devices Dec 29 13:10:29 joe-laptop kernel: [104324.762935] usb-storage: device found at 17 Dec 29 13:10:29 joe-laptop kernel: [104324.762938] usb-storage: waiting for device to settle before scanning Dec 29 13:10:34 joe-laptop kernel: [104329.760521] usb-storage: device scan complete Dec 29 13:10:34 joe-laptop kernel: [104329.761344] scsi 8:0:0:0: CD-ROM TEAC CD-224E 1.7A PQ: 0 ANSI: 0 CCS Dec 29 13:10:34 joe-laptop kernel: [104329.767425] sr1: scsi3-mmc drive: 24x/24x cd/rw xa/form2 cdda tray Dec 29 13:10:34 joe-laptop kernel: [104329.767612] sr 8:0:0:0: Attached scsi CD-ROM sr1 Dec 29 13:10:34 joe-laptop kernel: [104329.767720] sr 8:0:0:0: Attached scsi generic sg2 type 5 Dec 29 13:10:34 joe-laptop kernel: [104330.141060] sr 8:0:0:0: [sr1] Result: hostbyte=DID_OK driverbyte=DRIVER_SENSE Dec 29 13:10:34 joe-laptop kernel: [104330.141069] sr 8:0:0:0: [sr1] Sense Key : Illegal Request [current] Dec 29 13:10:34 joe-laptop kernel: [104330.141077] Info fld=0x0, ILI Dec 29 13:10:34 joe-laptop kernel: [104330.141081] sr 8:0:0:0: [sr1] Add. Sense: Illegal mode for this track Dec 29 13:10:34 joe-laptop kernel: [104330.141090] sr 8:0:0:0: [sr1] CDB: Read(10): 28 00 00 00 00 00 00 00 02 00 Dec 29 13:10:34 joe-laptop kernel: [104330.141106] end_request: I/O error, dev sr1, sector 0 Dec 29 13:10:34 joe-laptop kernel: [104330.141113] __ratelimit: 18 callbacks suppressed There was more output than this (the number of lines started growing after the drive was plugged back in, and kept growing), but this is the first few lines.

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  • Do NOT Change "Copy Local” project references to false, unless understand subsequences.

    - by Michael Freidgeim
    To optimize performance of visual studio build I've found multiple recommendations to change CopyLocal property for dependent dlls to false,e.g. From http://stackoverflow.com/questions/690033/best-practices-for-large-solutions-in-visual-studio-2008 CopyLocal? For sure turn this offhttp://stackoverflow.com/questions/280751/what-is-the-best-practice-for-copy-local-and-with-project-referencesAlways set the Copy Local property to false and enforce this via a custom msbuild stephttp://codebetter.com/patricksmacchia/2007/06/20/benefit-from-the-c-and-vb-net-compilers-perf/BenefitBenefitMy advice is to always set ‘Copy Local’ to falseSome time ago we've tried to change the setting to false, and found that it causes problem for deployment of top-level projects.Recently I've followed the suggestion and changed the settings for middle-level projects. It didn't cause immediate issues, but I was warned by Readify Consultant Colin Savage about possible errors during deploymentsI haven't undone the changes immediately and we found a few issues during testing.There are many scenarios, when you need to have Copy Local’ left to True.The concerns are highlighted in some stack overflow answers, but they have small number of votes.Top-level projects:  set copy local = true.First of all, it doesn't work correctly for top-level projects, i.e. executables or web sites.As pointed in the answer http://stackoverflow.com/a/6529461/52277for all the references in the one at the top set copy local = true.Alternatively you have to change output directory as it's described in http://www.simple-talk.com/dotnet/.net-framework/partitioning-your-code-base-through-.net-assemblies-and-visual-studio-projects/If you set ‘ Copy Local = false’, VS will, unless you tell it otherwise, place each assembly alone in its own .\bin\Debugdirectory. Because of this, you will need to configure VS to place assemblies together in the same directory. To do so, for each VS project, go to VS > Project Properties > Build tab > Output path, and set the Ouput path to ..\bin\Debugfor debug configuration, and ..\bin\Release for release configuration.Second-level  dependencies:  set copy local = true.Another example when copylocal =false fails on run-time, is when top level assembly doesn't directly referenced one of indirect dependencies.E..g. Top-level assembly A has reference to assembly B with copylocal =true, but assembly B has reference to assembly C with copylocal =false. Most likely assembly C will be missing on runtime and will cause errors E.g. http://stackoverflow.com/questions/602765/when-should-copy-local-be-set-to-true-and-when-should-it-not?lq=1Copy local is important for deployment scenarios and tools. As a general rule you should use CopyLocal=True and http://stackoverflow.com/questions/602765/when-should-copy-local-be-set-to-true-and-when-should-it-not?lq=1 Unfortunately there are some quirks and CopyLocal won't necessary work as expected for assembly references in secondary assemblies structured as shown below.MainApp.exe MyLibrary.dll ThirdPartyLibrary.dll (if in the GAC CopyLocal won't copy to MainApp bin folder)This makes xcopy deployments difficult . .Reflection called DLLs  dependencies:  set copy local = true.E.g user can see error "ISystem.Reflection.ReflectionTypeLoadException: Unable to load one or more of the requested types. Retrieve the LoaderExceptions property for more information."The fix for the issue is recommended in http://stackoverflow.com/a/6200173/52277"I solved this issue by setting the Copy Local attribute of my project's references to true."In general, the problems with investigation of deployment issues may overweight the benefits of reduced build time. Setting the Copy Local to false without considering deployment issues is not a good idea.

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  • Your Job Search Should be More Than Just a New Year's Resolution

    - by david.talamelli
    I love the beginning of a new year, it is a great chance to refocus and either re-evaluate goals you are working to or even set new ones. I don't have any statistics to measure this but I am sure that one of the more popular new year's resolutions in the general workforce is to either get a new job or work to further develop one's career. I think this is a good idea, in today's competitive work force people should have a plan of what they want to do, what role they are after and how to get there. One common mistake I think many people make though is that a career plan shouldn't be a once a year thought. When people finish with the holiday season with their new year's resolution to find a new job fresh in their mind, you can see the enthusiasm and motivation a person has to make something happen. Emails are sent, calls are made, applications are made, networking is happening, etc..... Finding the right role that you are after however can be difficult, while it would be great if that dream role was available just at the time you happened to be looking for it - in reality this is not always the case. Job Seekers need to keep reminding themselves that while sometimes that dream job they are after is available at the same time they are looking, that also a Job search can be a difficult and long process. Many people who set out with the best of intentions in January to find a new job can soon lose interest in a job search if they do not immediately find a role. Just like the Christmas decorations are put away and the photos from New Year's are stored away - a Job Seeker's motivation may slowly decrease until that person finds themselves 12 months later in the same situation in same role and looking for that new opportunity again. Rather than just "going for it" and looking for a role in the month of January, a person's job search or career plan should be an ongoing activity and thought process that is constantly updated and evaluated over the course of the year. It can be hard to stay motivated over an extended period of time, especially when you are newly motivated and ready for that new role and the results are not immediate. Rather than letting your job search fall down the priority list and into the "too hard basket" a few ideas that may keep your enthusiasm fresh Update your resume every 6 months, even if you are not looking for a job - it is easy to forget what you have accomplished if you don't keep your details updated. Also it is good to be prepared and have a resume ready to go in case you do get an unexpected phone call for that 'dream job' you have been hoping for. Work out what you want out of your next role before you begin your job search - rather than aimlessly searching job ads or talking to people - think of the organisations or type of role you would like before you search. If you know what you are looking for it will be much easier to work out how to get there than if you do not know what you want. Don't expect immediate results once you decide to look for another job, things don't always fall into place. Timing and delivery can be important pieces of being selected for a role, companies don't hire every role in January. Have an open mind - people you meet or talk to may not result in immediate results for your job search but every connection may help you get a bit closer to what you are after . These actions will not guarantee a positive result, but in today's competitive work force every little of extra preparation and planning helps. All the best for 2011 and I hope your career plan whatever it may be is a success.

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  • Building a Mafia&hellip;TechFest Style

    - by David Hoerster
    It’s been a few months since I last blogged (not that I blog much to begin with), but things have been busy.  We all have a lot going on in our lives, but I’ve had one item that has taken up a surprising amount of time – Pittsburgh TechFest 2012.  After the event, I went through some minutes of the first meetings for TechFest, and I started to think about how it all came together.  I think what inspired me the most about TechFest was how people from various technical communities were able to come together and build and promote a common event.  As a result, I wanted to blog about this to show that people from different communities can work together to build something that benefits all communities.  (Hopefully I've got all my facts straight.)  TechFest started as an idea Eric Kepes and myself had when we were planning our next Pittsburgh Code Camp, probably in the summer of 2011.  Our Spring 2011 Code Camp was a little different because we had a great infusion of some folks from the Pittsburgh Agile group (especially with a few speakers from LeanDog).  The line-up was great, but we felt our audience wasn’t as broad as it should have been.  We thought it would be great to somehow attract other user groups around town and have a big, polyglot conference. We started contacting leaders from Pittsburgh’s various user groups.  Eric and I split up the ones that we knew about, and we just started making contacts.  Most of the people we started contacting never heard of us, nor we them.  But we all had one thing in common – we ran user groups who’s primary goal is educating our members to make them better at what they do. Amazingly, and I say this because I wasn’t sure what to expect, we started getting some interest from the various leaders.  One leader, Greg Akins, is, in my opinion, Pittsburgh’s poster boy for the polyglot programmer.  He’s helped us in the past with .NET Code Camps, is a Java developer (and leader in Pittsburgh’s Java User Group), works with Ruby and I’m sure a handful of other languages.  He helped make some e-introductions to other user group leaders, and the whole thing just started to snowball. Once we realized we had enough interest with the user group leaders, we decided to not have a Fall Code Camp and instead focus on this new entity. Flash-forward to October of 2011.  I set up a meeting, with the help of Jeremy Jarrell (Pittsburgh Agile leader) to hold a meeting with the leaders of many of Pittsburgh technical user groups.  We had representatives from 12 technical user groups (Python, JavaScript, Clojure, Ruby, PittAgile, jQuery, PHP, Perl, SQL, .NET, Java and PowerShell) – 14 people.  We likened it to a scene from a Godfather movie where the heads of all the families come together to make some deal.  As a result, the name “TechFest Mafia” was born and kind of stuck. Over the next 7 months or so, we had our starts and stops.  There were moments where I thought this event would not happen either because we wouldn’t have the right mix of topics (was I off there!), or enough people register (OK, I was wrong there, too!) or find an appropriate venue (hmm…wrong there, too) or find enough sponsors to help support the event (wow…not doing so well).  Overall, everything fell into place with a lot of hard work from Eric, Jen, Greg, Jeremy, Sean, Nicholas, Gina and probably a few others that I’m forgetting.  We also had a bit of luck, too.  But in the end, the passion that we had to put together an event that was really about making ourselves better at what we do really paid off. I’ve never been more excited about a project coming together than I have been with Pittsburgh TechFest 2012.  From the moment the first person arrived at the event to the final minutes of my closing remarks (where I almost lost my voice – I ended up being diagnosed with bronchitis the next day!), it was an awesome event.  I’m glad to have been part of bringing something like this to Pittsburgh…and I’m looking forward to Pittsburgh TechFest 2013.  See you there!

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  • Many Stack Overflow users' pages have no Google PageRank and they are not indexed, why?

    - by Marco Demaio
    If you go to my user page on Stack Overflow and you check it with the Google Toolbar, you can see it has no PageRank at all (this does happen for almost any user page, even people with much higher reputation, the only exceptions seem to be the users in page 1, and some other users they have PR). My user page's Page Rank is not only zero, but not calculated at all. When PR is 0 or less than 1, but calculated the Google bar shows white, but when the PR is not even calculated like in my user page the Google bar shows in grey. I further more discovered that my user page is NOT EVEN INDEXED on Google, simple test is searching on Google for the exact page url: "http://stackoverflow.com/users/260080/marco-demaio" and you will see no result. The question is how can this be??? This is really weird to me because of the following reason: If you search on Google for "Marco Demaio" on Stack Overflow only (you can do this by searching "site:stackoverflow.com Marco Demaio") the search result shows hundreds of 'asking/answering questions' pages where I was 'tagged'!!! Let's check one of these: the 1st one that appears now (shows one of the question I asked). We can be sure this page is indexed in Google because comes out in a search. Moreover, its PR is calculated. It's probably nearly zero. Still, some PR flows there, the PR bar is not grey, but white: The page shown above has got links to my own user page. I checked the source code of the page shown above and the links are not hidden or set with a rel="nofollow", moreover I can't see any meta character excluding the links on the page from being followed. So what's happening? Why Google does not see my user page at all. Did Stack Overflow do something to achieve this? If yes what did they do? Any explanation really appreciates (as always). P.S. obviously I checked also the code of my user page, but I could not find meta tags excluding Google search for the page. P.S. 2 in a desperate adventure I also checked Stack Overflow's robots.txt but it does not seem to exclude user pages. UPDATE 1 following up on some answers, I did some more research. Excluding for a while the PR problem (since PR is not science), and looking only at the user page on Stack Overflow NOT BEING INDEXED problem: pages do not seem to be indexed by Google because of the user reputation, this user for instance has got NOW 200 points less reputation than me and his page is indexed (while mine not). It does not seem even to be connected with months you have been on Stack Overflow, this user (almost my same reputation) has been there for 3 months only and his page is indexed (while mine not and I have been a user for 7 months). It's bizarre! UPDATE February/2011 As of today, the page got indexed by Google at least when you search for "site:stackoverflow.com Marco Demaio" it's the 1st page. The amazing thing is that it has still got NO PageRank at all: Google toolbar states loud and clear "No PageRank information available". It's odd!

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  • July, the 31 Days of SQL Server DMO’s – Day 23 (sys.dm_db_index_usage_stats)

    - by Tamarick Hill
    The sys.dm_db_index_usage_stats Dynamic Management View is used to return usage information about the various indexes on your SQL Server instance. Let’s have a look at this DMV against our AdventureWorks2012 database so we can examine the information returned. SELECT * FROM sys.dm_db_index_usage_stats WHERE database_id = db_id('AdventureWorks2012') The first three columns in the result set represent the database_id, object_id, and index_id of a given row. You can join these columns back to other system tables to extract the actual database, object, and index names. The next four columns are probably the most beneficial columns within this DMV. First, the user_seeks column represents the number of times that a user query caused a seek operation against a particular index. The user_scans column represents how many times a user query caused a scan operation on a particular index. The user_lookups column represents how many times an index was used to perform a lookup operation. The user_updates column refers to how many times an index had to be updated due to a write operation that effected a particular index. The last_user_seek, last_user_scan, last_user_lookup, and last_user_update columns provide you with DATETIME information about when the last user scan, seek, lookup, or update operation was performed. The remaining columns in the result set are the same as the ones we previously discussed, except instead of the various operations being generated from user requests, they are generated from system background requests. This is an extremely useful DMV and one of my favorites when it comes to Index Maintenance. As we all know, indexes are extremely beneficial with improving the performance of your read operations. But indexes do have a downside as well. Indexes slow down the performance of your write operations, and they also require additional resources for storage. For this reason, in my opinion, it is important to regularly analyze the indexes on your system to make sure the indexes you have are being used efficiently. My AdventureWorks2012 database is only used for demonstrating or testing things, so I dont have a lot of meaningful information here, but for a Production system, if you see an index that is never getting any seeks, scans, or lookups, but is constantly getting a ton of updates, it more than likely would be a good candidate for you to consider removing. You would not be getting much benefit from the index, but yet it is incurring a cost on your system due to it constantly having to be updated for your write operations, not to mention the additional storage it is consuming. You should regularly analyze your indexes to ensure you keep your database systems as efficient and lean as possible. One thing to note is that these DMV statistics are reset every time SQL Server is restarted. Therefore it would not be a wise idea to make decisions about removing indexes after a Server Reboot or a cluster roll. If you restart your SQL Server instances frequently, for example if you schedule weekly/monthly cluster rolls, then you may not capture indexes that are being used for weekly/monthly reports that run for business users. And if you remove them, you may have some upset people at your desk on Monday morning. If you would like to begin analyzing your indexes to possibly remove the ones that your system is not using, I would recommend building a process to load this DMV information into a table on scheduled basis, depending on how frequently you perform an operation that would reset these statistics, then you can analyze the data over a period of time to get a more accurate view of what indexes are really being used and which ones or not. For more information about this DMV, please see the below Books Online link: http://msdn.microsoft.com/en-us/library/ms188755.aspx Follow me on Twitter @PrimeTimeDBA

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  • ASP.NET MVC CRUD Validation

    - by Ricardo Peres
    One thing I didn’t refer on my previous post on ASP.NET MVC CRUD with AJAX was how to retrieve model validation information into the client. We want to send any model validation errors to the client in the JSON object that contains the ProductId, RowVersion and Success properties, specifically, if there are any errors, we will add an extra Errors collection property. Here’s how: 1: [HttpPost] 2: [AjaxOnly] 3: [Authorize] 4: public JsonResult Edit(Product product) 5: { 6: if (this.ModelState.IsValid == true) 7: { 8: using (ProductContext ctx = new ProductContext()) 9: { 10: Boolean success = false; 11:  12: ctx.Entry(product).State = (product.ProductId == 0) ? EntityState.Added : EntityState.Modified; 13:  14: try 15: { 16: success = (ctx.SaveChanges() == 1); 17: } 18: catch (DbUpdateConcurrencyException) 19: { 20: ctx.Entry(product).Reload(); 21: } 22:  23: return (this.Json(new { Success = success, ProductId = product.ProductId, RowVersion = Convert.ToBase64String(product.RowVersion) })); 24: } 25: } 26: else 27: { 28: Dictionary<String, String> errors = new Dictionary<String, String>(); 29:  30: foreach (KeyValuePair<String, ModelState> keyValue in this.ModelState) 31: { 32: String key = keyValue.Key; 33: ModelState modelState = keyValue.Value; 34:  35: foreach (ModelError error in modelState.Errors) 36: { 37: errors[key] = error.ErrorMessage; 38: } 39: } 40:  41: return (this.Json(new { Success = false, ProductId = 0, RowVersion = String.Empty, Errors = errors })); 42: } 43: } As for the view, we need to change slightly the onSuccess JavaScript handler on the Single view: 1: function onSuccess(ctx) 2: { 3: if (typeof (ctx.Success) != 'undefined') 4: { 5: $('input#ProductId').val(ctx.ProductId); 6: $('input#RowVersion').val(ctx.RowVersion); 7:  8: if (ctx.Success == false) 9: { 10: var errors = ''; 11:  12: if (typeof (ctx.Errors) != 'undefined') 13: { 14: for (var key in ctx.Errors) 15: { 16: errors += key + ': ' + ctx.Errors[key] + '\n'; 17: } 18:  19: window.alert('An error occurred while updating the entity: the model contained the following errors.\n\n' + errors); 20: } 21: else 22: { 23: window.alert('An error occurred while updating the entity: it may have been modified by third parties. Please try again.'); 24: } 25: } 26: else 27: { 28: window.alert('Saved successfully'); 29: } 30: } 31: else 32: { 33: if (window.confirm('Not logged in. Login now?') == true) 34: { 35: document.location.href = '<% 1: : FormsAuthentication.LoginUrl %>?ReturnURL=' + document.location.pathname; 36: } 37: } 38: } The logic is as this: If the Edit action method is called for a new entity (the ProductId is 0) and it is valid, the entity is saved, and the JSON results contains a Success flag set to true, a ProductId property with the database-generated primary key and a RowVersion with the server-generated ROWVERSION; If the model is not valid, the JSON result will contain the Success flag set to false and the Errors collection populated with all the model validation errors; If the entity already exists in the database (ProductId not 0) and the model is valid, but the stored ROWVERSION is different that the one on the view, the result will set the Success property to false and will return the current (as loaded from the database) value of the ROWVERSION on the RowVersion property. On a future post I will talk about the possibilities that exist for performing model validation, stay tuned!

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  • Reconciling the Boy Scout Rule and Opportunistic Refactoring with code reviews

    - by t0x1n
    I am a great believer in the Boy Scout Rule: Always check a module in cleaner than when you checked it out." No matter who the original author was, what if we always made some effort, no matter how small, to improve the module. What would be the result? I think if we all followed that simple rule, we'd see the end of the relentless deterioration of our software systems. Instead, our systems would gradually get better and better as they evolved. We'd also see teams caring for the system as a whole, rather than just individuals caring for their own small little part. I am also a great believer in the related idea of Opportunistic Refactoring: Although there are places for some scheduled refactoring efforts, I prefer to encourage refactoring as an opportunistic activity, done whenever and wherever code needs to cleaned up - by whoever. What this means is that at any time someone sees some code that isn't as clear as it should be, they should take the opportunity to fix it right there and then - or at least within a few minutes Particularly note the following excerpt from the refactoring article: I'm wary of any development practices that cause friction for opportunistic refactoring ... My sense is that most teams don't do enough refactoring, so it's important to pay attention to anything that is discouraging people from doing it. To help flush this out be aware of any time you feel discouraged from doing a small refactoring, one that you're sure will only take a minute or two. Any such barrier is a smell that should prompt a conversation. So make a note of the discouragement and bring it up with the team. At the very least it should be discussed during your next retrospective. Where I work, there is one development practice that causes heavy friction - Code Review (CR). Whenever I change anything that's not in the scope of my "assignment" I'm being rebuked by my reviewers that I'm making the change harder to review. This is especially true when refactoring is involved, since it makes "line by line" diff comparison difficult. This approach is the standard here, which means opportunistic refactoring is seldom done, and only "planned" refactoring (which is usually too little, too late) takes place, if at all. I claim that the benefits are worth it, and that 3 reviewers will work a little harder (to actually understand the code before and after, rather than look at the narrow scope of which lines changed - the review itself would be better due to that alone) so that the next 100 developers reading and maintaining the code will benefit. When I present this argument my reviewers, they say they have no problem with my refactoring, as long as it's not in the same CR. However I claim this is a myth: (1) Most of the times you only realize what and how you want to refactor when you're in the midst of your assignment. As Martin Fowler puts it: As you add the functionality, you realize that some code you're adding contains some duplication with some existing code, so you need to refactor the existing code to clean things up... You may get something working, but realize that it would be better if the interaction with existing classes was changed. Take that opportunity to do that before you consider yourself done. (2) Nobody is going to look favorably at you releasing "refactoring" CRs you were not supposed to do. A CR has a certain overhead and your manager doesn't want you to "waste your time" on refactoring. When it's bundled with the change you're supposed to do, this issue is minimized. The issue is exacerbated by Resharper, as each new file I add to the change (and I can't know in advance exactly which files would end up changed) is usually littered with errors and suggestions - most of which are spot on and totally deserve fixing. The end result is that I see horrible code, and I just leave it there. Ironically, I feel that fixing such code not only will not improve my standings, but actually lower them and paint me as the "unfocused" guy who wastes time fixing things nobody cares about instead of doing his job. I feel bad about it because I truly despise bad code and can't stand watching it, let alone call it from my methods! Any thoughts on how I can remedy this situation ?

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  • SQL SERVER – A Puzzle – Swap Value of Column Without Case Statement

    - by pinaldave
    For the last few weeks, I have been doing Friday Puzzles and I am really loving it. Yesterday I received a very interesting question by Navneet Chaurasia on Facebook Page. He was asked this question in one of the interview questions for job. Please read the original thread for a complete idea of the conversation. I am presenting the same question here. Puzzle Let us assume there is a single column in the table called Gender. The challenge is to write a single update statement which will flip or swap the value in the column. For example if the value in the gender column is ‘male’ swap it with ‘female’ and if the value is ‘female’ swap it with ‘male’. Here is the quick setup script for the puzzle. USE tempdb GO CREATE TABLE SimpleTable (ID INT, Gender VARCHAR(10)) GO INSERT INTO SimpleTable (ID, Gender) SELECT 1, 'female' UNION ALL SELECT 2, 'male' UNION ALL SELECT 3, 'male' GO SELECT * FROM SimpleTable GO The above query will return following result set. The puzzle was to write a single update column which will generate following result set. There are multiple answers to this simple puzzle. Let me show you three different ways. I am assuming that the column will have either value ‘male’ or ‘female’ only. Method 1: Using CASE Statement I believe this is going to be the most popular solution as we are all familiar with CASE Statement. UPDATE SimpleTable SET Gender = CASE Gender WHEN 'male' THEN 'female' ELSE 'male' END GO SELECT * FROM SimpleTable GO Method 2: Using REPLACE  Function I totally understand it is the not cleanest solution but it will for sure work in giving situation. UPDATE SimpleTable SET Gender = REPLACE(('fe'+Gender),'fefe','') GO SELECT * FROM SimpleTable GO Method 3: Using IIF in SQL Server 2012 If you are using SQL Server 2012 you can use IIF and get the same effect as CASE statement. UPDATE SimpleTable SET Gender = IIF(Gender = 'male', 'female', 'male') GO SELECT * FROM SimpleTable GO You can read my article series on SQL Server 2012 various functions over here. SQL SERVER – Denali – Logical Function – IIF() – A Quick Introduction SQL SERVER – Detecting Leap Year in T-SQL using SQL Server 2012 – IIF, EOMONTH and CONCAT Function Let us clean up. DROP TABLE SimpleTable GO Question to you: I came up with three simple tricks where there is a single UPDATE statement which swaps the values in the column. Do you know any other simple trick? If yes, please post here in the comments. I will pick two random winners from all the valid answers. Winners will get 1) Print Copy of SQL Server Interview Questions and Answers 2) Free Learning Code for Online Video Courses I will announce the winners on coming Monday. Reference:  Pinal Dave (http://blog.SQLAuthority.com) Filed under: CodeProject, PostADay, SQL, SQL Authority, SQL Interview Questions and Answers, SQL Puzzle, SQL Query, SQL Server, SQL Tips and Tricks, SQLServer, T SQL, Technology

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  • SEO: many stackoverflow users' pages have got no Google PR and they are not indexed, why?

    - by Marco Demaio
    If you go to my user page on Stack Overflow and you check it with the Gogle bar you can see has got no PR at all (this does happen for almost any user page, even people with much higher reputation, the only exceptions seem to be the users in page 1, and some other users they have PR). My user page's Page Rank is not only zero, but not calculated at all. When PR is 0 or less than 1, but calculated the Google bar shows white, but when the PR is not even calculated like in my user page the Google bar shows in grey. I further more discovered that my user page is NOT EVEN INDEXED on Google, simple test is searching on Google for the exact page url: "http://stackoverflow.com/users/260080/marco-demaio" and you will see no result. The question is how can this be??? This is really weird to me because of the following reason: If you search on Google for "Marco Demaio" on stackoverflow site only (you can do this by searching "site:stackoverflow.com Marco Demaio") the search result shows hundreds of 'asking/answering questions' pages where I was 'tagged'!!! Let's check one of these: the 1st one that appears now (shows one of the question I asked). We can be sure this page is indexed in Google because comes out in a search moreover its PR is calculated, it's probably nearly zero, but still some PR flows there, the PR bar is not grey, but white: The page shown above has got links to my own user page. I checked the source code of the page shown above and the links are not hidden or set with a rel="nofollow", moreover I can't see any meta character excluding the links on the page from being followed. So what's happening? Why Google does not see my user page at all. Did stackoverflow do something to achieve this? If yes what did they do? Any explantion really appreciates (as always). P.S. obviously I checked also the code of my user page, but I could not find meta tags excluding Google search for the page. P.S. 2 in a desperate adventure I also checked StackOverflow robots but it does not seem to exclude user pages. UPDATE 1 following up on some answers, I did some more research. Excluding for a while the PR problem (since PR is not science), and looking only at the user page on StackOverflow NOT BEING INDEXED problem: pages do not seem to be indexed by Google because of the user reputation, this user for instance has got NOW 200 points less reputation than me and his page is indexed (while mine not). It does not seem even to be connected with months you have been on Stackoverflow, this user (almost my same reputation) has been there for 3 months only and his page is indexed (while mine not and I have been a user for 7 months). It's bizzarre! UPDATE February/2011 As of today the page got indexed by Google at least when you search for "site:stackoverflow.com Marco Demaio" it's the 1st page. The amazing thing is that it has still got NO PageRank at all: Google toolbar states loud and clear "No PageRank information available". It's odd!

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  • MP3 player mpman TS300 not recognized

    - by Nick Lemaire
    I just received a mpman ts300 mp3 player for Christmas. But when I try to connect it to ubuntu (10.10) through usb it doesn't seem to be recognized. I searched for a linuxdriver but came up with nothing. I even tried installing mpman manager from the software center, but still the same problem... Has anybody got any ideas about how to fix this? Thank you edit: some additional information When I plug it in, it doesn't show up under /dev. And it is not listed in the result of 'lsusb' This is the output of 'dmesg' [19571.732541] usb 1-4: new high speed USB device using ehci_hcd and address 2 [19571.889154] scsi7 : usb-storage 1-4:1.0 [19572.883155] scsi 7:0:0:0: Direct-Access TS300 USB DISK 1.00 PQ: 0 ANSI: 0 [19572.885856] sd 7:0:0:0: Attached scsi generic sg2 type 0 [19572.887266] sd 7:0:0:0: [sdb] 7868416 512-byte logical blocks: (4.02 GB/3.75 GiB) [19573.012547] usb 1-4: reset high speed USB device using ehci_hcd and address 2 [19573.292550] usb 1-4: reset high speed USB device using ehci_hcd and address 2 [19573.572565] usb 1-4: reset high speed USB device using ehci_hcd and address 2 [19573.725019] sd 7:0:0:0: [sdb] Test WP failed, assume Write Enabled [19573.725024] sd 7:0:0:0: [sdb] Assuming drive cache: write through [19573.728521] sd 7:0:0:0: [sdb] Attached SCSI removable disk [19575.333015] sd 7:0:0:0: [sdb] 7868416 512-byte logical blocks: (4.02 GB/3.75 GiB) [19575.452547] usb 1-4: reset high speed USB device using ehci_hcd and address 2 [19580.603253] usb 1-4: device descriptor read/all, error -110 [19580.722560] usb 1-4: reset high speed USB device using ehci_hcd and address 2 [19595.842579] usb 1-4: device descriptor read/64, error -110 [19611.072656] usb 1-4: device descriptor read/64, error -110 [19611.302540] usb 1-4: reset high speed USB device using ehci_hcd and address 2 [19616.332568] usb 1-4: device descriptor read/8, error -110 [19621.462692] usb 1-4: device descriptor read/8, error -110 [19621.692551] usb 1-4: reset high speed USB device using ehci_hcd and address 2 [19626.722567] usb 1-4: device descriptor read/8, error -110 [19631.852802] usb 1-4: device descriptor read/8, error -110 [19631.962587] usb 1-4: USB disconnect, address 2 [19631.962587] sd 7:0:0:0: Device offlined - not ready after error recovery [19631.962840] sd 7:0:0:0: [sdb] Assuming drive cache: write through [19631.965104] sd 7:0:0:0: [sdb] READ CAPACITY failed [19631.965109] sd 7:0:0:0: [sdb] Result: hostbyte=DID_NO_CONNECT driverbyte=DRIVER_OK [19631.965112] sd 7:0:0:0: [sdb] Sense not available. [19631.965125] sd 7:0:0:0: [sdb] Assuming drive cache: write through [19631.965130] sdb: detected capacity change from 4028628992 to 0 [19632.130042] usb 1-4: new high speed USB device using ehci_hcd and address 3 [19647.242550] usb 1-4: device descriptor read/64, error -110 [19662.472560] usb 1-4: device descriptor read/64, error -110 [19662.702566] usb 1-4: new high speed USB device using ehci_hcd and address 4 [19677.822587] usb 1-4: device descriptor read/64, error -110 [19693.052575] usb 1-4: device descriptor read/64, error -110 [19693.282582] usb 1-4: new high speed USB device using ehci_hcd and address 5 [19698.312600] usb 1-4: device descriptor read/8, error -110 [19703.442594] usb 1-4: device descriptor read/8, error -110 [19703.672548] usb 1-4: new high speed USB device using ehci_hcd and address 6 [19708.702581] usb 1-4: device descriptor read/8, error -110 [19713.840077] usb 1-4: device descriptor read/8, error -110 [19713.942555] hub 1-0:1.0: unable to enumerate USB device on port 4 [19714.262545] usb 4-2: new full speed USB device using uhci_hcd and address 2 [19729.382549] usb 4-2: device descriptor read/64, error -110 [19744.612534] usb 4-2: device descriptor read/64, error -110 [19744.842543] usb 4-2: new full speed USB device using uhci_hcd and address 3 [19759.962714] usb 4-2: device descriptor read/64, error -110 [19775.200047] usb 4-2: device descriptor read/64, error -110 [19775.422630] usb 4-2: new full speed USB device using uhci_hcd and address 4 [19780.444498] usb 4-2: device descriptor read/8, error -110 [19785.574491] usb 4-2: device descriptor read/8, error -110 [19785.802547] usb 4-2: new full speed USB device using uhci_hcd and address 5 [19790.824490] usb 4-2: device descriptor read/8, error -110 [19795.961473] usb 4-2: device descriptor read/8, error -110 [19796.062556] hub 4-0:1.0: unable to enumerate USB device on port 2

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  • Floating Panels and Describe Windows in Oracle SQL Developer

    - by thatjeffsmith
    One of the challenges I face as I try to share tips about our software is that I tend to assume there are features that you just ‘know about.’ Either they’re so intuitive that you MUST know about them, or it’s a feature that I’ve been using for so long I forget that others may have never even seen it before. I want to cover two of those today - Describe (DESC) – SHIFT+F4 Floating Panels My super-exciting desktop SQL Developer and Describe DESC or Describe is an Oracle SQL*Plus command. It shows what a table or view is composed of in terms of it’s column definition. Here’s an example: SQL*Plus: Release 11.2.0.3.0 Production on Fri Sep 21 14:25:37 2012 Copyright (c) 1982, 2011, Oracle. All rights reserved. Connected to: Oracle Database 11g Enterprise Edition Release 11.2.0.3.0 - Production With the Partitioning, OLAP, Data Mining and Real Application Testing options SQL> desc beer; Name Null? Type ----------------------------------------- -------- ---------------------------- BREWERY NOT NULL VARCHAR2(100) CITY VARCHAR2(100) STATE VARCHAR2(100) COUNTRY VARCHAR2(100) ID NUMBER SQL> You can get the same information – and a good bit more – in SQL Developer using the SQL Developer DESC command. You invoke it with SHIFT+F4. It will open a floating (non-modal!) window with the information you want. Here’s an example: I can see my column definitions, constratins, stats, privs, etc A few ‘cool’ things you should be aware of: I can open as many as I want, and still work in my worksheet, browser, etc. I can also DESC an index, user, or most any other database object I can of course move them off my primary desktop display The DESC panel’s are read-only. I can’t drop a constraint from within the DESC window of a given table. But for dragging columns into my worksheet, and checking out the stats for my objects as I query them – it’s very, very handy. Try This Right Now Type ‘scott.emp’ (or some other table you have), place your cursor on the text, and hit SHIFT+F4. You’ll see the EMP object open. Now click into a column name in the columns page. Drag it into your worksheet. It will paste that column name into your query. This is an alternative for those that don’t like our code insight feature or dragging columns off the connection tree (new for v3.2!) Got it? SQL Developer’s Floating Panels Ok, let’s talk about a similar feature. Did you know that any dockable panel from the View menu can also be ‘floated?’ One of my favorite features is the SQL History. Every query I run is recorded, and I can recall them later without having to remember what I ran and when. And I USUALLY use the keyboard shortcuts for this. Let your trouble float away…if only it were so easy as a right-click in the real world. But sometimes I still want to see my recall list without having to give up my screen real estate. So I just mouse-right click on the panel tab and select ‘Float.’ Then I move it over to my secondary display – see the poorly lit picture in the beginning of this post. And that’s it. Simple, I know. But I thought you should know about these two things!

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  • ODI 11g – Oracle Multi Table Insert

    - by David Allan
    With the IKM Oracle Multi Table Insert you can generate Oracle specific DML for inserting into multiple target tables from a single query result – without reprocessing the query or staging its result. When designing this to exploit the IKM you must split the problem into the reusable parts – the select part goes in one interface (I named SELECT_PART), then each target goes in a separate interface (INSERT_SPECIAL and INSERT_REGULAR). So for my statement below… /*INSERT_SPECIAL interface */ insert  all when 1=1 And (INCOME_LEVEL > 250000) then into SCOTT.CUSTOMERS_NEW (ID, NAME, GENDER, BIRTH_DATE, MARITAL_STATUS, INCOME_LEVEL, CREDIT_LIMIT, EMAIL, USER_CREATED, DATE_CREATED, USER_MODIFIED, DATE_MODIFIED) values (ID, NAME, GENDER, BIRTH_DATE, MARITAL_STATUS, INCOME_LEVEL, CREDIT_LIMIT, EMAIL, USER_CREATED, DATE_CREATED, USER_MODIFIED, DATE_MODIFIED) /* INSERT_REGULAR interface */ when 1=1  then into SCOTT.CUSTOMERS_SPECIAL (ID, NAME, GENDER, BIRTH_DATE, MARITAL_STATUS, INCOME_LEVEL, CREDIT_LIMIT, EMAIL, USER_CREATED, DATE_CREATED, USER_MODIFIED, DATE_MODIFIED) values (ID, NAME, GENDER, BIRTH_DATE, MARITAL_STATUS, INCOME_LEVEL, CREDIT_LIMIT, EMAIL, USER_CREATED, DATE_CREATED, USER_MODIFIED, DATE_MODIFIED) /*SELECT*PART interface */ select        CUSTOMERS.EMAIL EMAIL,     CUSTOMERS.CREDIT_LIMIT CREDIT_LIMIT,     UPPER(CUSTOMERS.NAME) NAME,     CUSTOMERS.USER_MODIFIED USER_MODIFIED,     CUSTOMERS.DATE_MODIFIED DATE_MODIFIED,     CUSTOMERS.BIRTH_DATE BIRTH_DATE,     CUSTOMERS.MARITAL_STATUS MARITAL_STATUS,     CUSTOMERS.ID ID,     CUSTOMERS.USER_CREATED USER_CREATED,     CUSTOMERS.GENDER GENDER,     CUSTOMERS.DATE_CREATED DATE_CREATED,     CUSTOMERS.INCOME_LEVEL INCOME_LEVEL from    SCOTT.CUSTOMERS   CUSTOMERS where    (1=1) Firstly I create a SELECT_PART temporary interface for the query to be reused and in the IKM assignment I state that it is defining the query, it is not a target and it should not be executed. Then in my INSERT_SPECIAL interface loading a target with a filter, I set define query to false, then set true for the target table and execute to false. This interface uses the SELECT_PART query definition interface as a source. Finally in my final interface loading another target I set define query to false again, set target table to true and execute to true – this is the go run it indicator! To coordinate the statement construction you will need to create a package with the select and insert statements. With 11g you can now execute the package in simulation mode and preview the generated code including the SQL statements. Hopefully this helps shed some light on how you can leverage the Oracle MTI statement. A similar IKM exists for Teradata. The ODI IKM Teradata Multi Statement supports this multi statement request in 11g, here is an extract from the paper at www.teradata.com/white-papers/born-to-be-parallel-eb3053/ Teradata Database offers an SQL extension called a Multi-Statement Request that allows several distinct SQL statements to be bundled together and sent to the optimizer as if they were one. Teradata Database will attempt to execute these SQL statements in parallel. When this feature is used, any sub-expressions that the different SQL statements have in common will be executed once, and the results shared among them. It works in the same way as the ODI MTI IKM, multiple interfaces orchestrated in a package, each interface contributes some SQL, the last interface in the chain executes the multi statement.

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  • Gnome Shell Theme Problem on Ubuntu 11.10

    - by Khurram Majeed
    I am trying to install ANewStart GNOME shell themes on Ubuntu 11.10. I have installed gnome shell extension for themes: sudo add-apt-repository ppa:webupd8team/gnome3 sudo apt-get update sudo apt-get install gnome-shell-extensions-user-theme I got the instructions from here ANewStart GNOME Shell Theme + AwOken Icons Theme = Pure Art. But when I go to "Advanced Settings - Shell Extensions" its empty... There is nothing. Also there is a orange triangle sign next to Shell Theme drop down in Advanced Settings - Theme. When I try to run the gnome-tweak-tool from terminal I get following error: imresh@imresh-laptop:~$ gnome-tweak-tool CRITICAL: Error parsing schema org.gnome.shell (/usr/share/glib-2.0/schemas/org.gnome.shell.gschema.xml) Traceback (most recent call last): File "/usr/lib/python2.7/dist-packages/gtweak/gsettings.py", line 45, in __init__ summary = key.getElementsByTagName("summary")[0].childNodes[0].data IndexError: list index out of range WARNING : Error detecting shell Traceback (most recent call last): File "/usr/lib/python2.7/dist-packages/gtweak/tweaks/tweak_shell_extensions.py", line 145, in __init__ shell = GnomeShellFactory().get_shell() File "/usr/lib/python2.7/dist-packages/gtweak/utils.py", line 38, in getinstance instances[cls] = cls() File "/usr/lib/python2.7/dist-packages/gtweak/gshellwrapper.py", line 123, in __init__ v = map(int,proxy.version.split(".")) File "/usr/lib/python2.7/dist-packages/gtweak/gshellwrapper.py", line 46, in version return json.loads(self.execute_js('const Config = imports.misc.config; Config.PACKAGE_VERSION')) File "/usr/lib/python2.7/dist-packages/gtweak/gshellwrapper.py", line 39, in execute_js result, output = self.proxy.Eval('(s)', js) File "/usr/lib/python2.7/dist-packages/gi/overrides/Gio.py", line 148, in __call__ kwargs.get('flags', 0), kwargs.get('timeout', -1), None) File "/usr/lib/python2.7/dist-packages/gi/types.py", line 43, in function return info.invoke(*args, **kwargs) GError: GDBus.Error:org.freedesktop.DBus.Error.ServiceUnknown: The name org.gnome.Shell was not provided by any .service files WARNING : Shell not running Traceback (most recent call last): File "/usr/lib/python2.7/dist-packages/gtweak/tweaks/tweak_shell.py", line 57, in __init__ self._shell = GnomeShellFactory().get_shell() File "/usr/lib/python2.7/dist-packages/gtweak/utils.py", line 38, in getinstance instances[cls] = cls() File "/usr/lib/python2.7/dist-packages/gtweak/gshellwrapper.py", line 123, in __init__ v = map(int,proxy.version.split(".")) File "/usr/lib/python2.7/dist-packages/gtweak/gshellwrapper.py", line 46, in version return json.loads(self.execute_js('const Config = imports.misc.config; Config.PACKAGE_VERSION')) File "/usr/lib/python2.7/dist-packages/gtweak/gshellwrapper.py", line 39, in execute_js result, output = self.proxy.Eval('(s)', js) File "/usr/lib/python2.7/dist-packages/gi/overrides/Gio.py", line 148, in __call__ kwargs.get('flags', 0), kwargs.get('timeout', -1), None) File "/usr/lib/python2.7/dist-packages/gi/types.py", line 43, in function return info.invoke(*args, **kwargs) GError: GDBus.Error:org.freedesktop.DBus.Error.ServiceUnknown: The name org.gnome.Shell was not provided by any .service files WARNING : Could not list shell extensions Traceback (most recent call last): File "/usr/lib/python2.7/dist-packages/gtweak/tweaks/tweak_shell.py", line 62, in __init__ extensions = self._shell.list_extensions() AttributeError: ShellThemeTweak instance has no attribute '_shell' (gnome-tweak-tool:5323): Gtk-CRITICAL **: gtk_widget_get_preferred_height_for_width: assertion `width >= 0' failed (gnome-tweak-tool:5323): Gtk-CRITICAL **: gtk_widget_get_preferred_height_for_width: assertion `width >= 0' failed (gnome-tweak-tool:5323): Gtk-CRITICAL **: gtk_widget_get_preferred_height_for_width: assertion `width >= 0' failed (gnome-tweak-tool:5323): Gtk-CRITICAL **: gtk_widget_get_preferred_height_for_width: assertion `width >= 0' failed (gnome-tweak-tool:5323): Gtk-CRITICAL **: gtk_widget_get_preferred_height_for_width: assertion `width >= 0' failed (gnome-tweak-tool:5323): Gtk-CRITICAL **: gtk_widget_get_preferred_height_for_width: assertion `width >= 0' failed (gnome-tweak-tool:5323): Gtk-CRITICAL **: gtk_widget_get_preferred_height_for_width: assertion `width >= 0' failed (gnome-tweak-tool:5323): Gtk-CRITICAL **: gtk_widget_get_preferred_height_for_width: assertion `width >= 0' failed (gnome-tweak-tool:5323): Gtk-CRITICAL **: gtk_widget_get_preferred_height_for_width: assertion `width >= 0' failed (gnome-tweak-tool:5323): Gtk-CRITICAL **: gtk_widget_get_preferred_height_for_width: assertion `width >= 0' failed (gnome-tweak-tool:5323): Gtk-CRITICAL **: gtk_widget_get_preferred_height_for_width: assertion `width >= 0' failed (gnome-tweak-tool:5323): Gtk-CRITICAL **: gtk_widget_get_preferred_height_for_width: assertion `width >= 0' failed (gnome-tweak-tool:5323): Gtk-CRITICAL **: gtk_widget_get_preferred_height_for_width: assertion `width >= 0' failed (gnome-tweak-tool:5323): Gtk-CRITICAL **: gtk_widget_get_preferred_height_for_width: assertion `width >= 0' failed (gnome-tweak-tool:5323): Gtk-CRITICAL **: gtk_widget_get_preferred_height_for_width: assertion `width >= 0' failed Please help me in fixing this. I have also restarted the computer many times it does not make a difference.

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  • SQL SERVER – Simple Demo of New Cardinality Estimation Features of SQL Server 2014

    - by Pinal Dave
    SQL Server 2014 has new cardinality estimation logic/algorithm. The cardinality estimation logic is responsible for quality of query plans and majorly responsible for improving performance for any query. This logic was not updated for quite a while, but in the latest version of SQL Server 2104 this logic is re-designed. The new logic now incorporates various assumptions and algorithms of OLTP and warehousing workload. Cardinality estimates are a prediction of the number of rows in the query result. The query optimizer uses these estimates to choose a plan for executing the query. The quality of the query plan has a direct impact on improving query performance. ~ Souce MSDN Let us see a quick example of how cardinality improves performance for a query. I will be using the AdventureWorks database for my example. Before we start with this demonstration, remember that even though you have SQL Server 2014 to see the effect of new cardinality estimates, you will need your database compatibility mode set to 120 which is for SQL Server 2014. If your server instance of SQL Server 2014 but you have set up your database compatibility mode to 110 or any other earlier version, you will get performance from your query like older version of SQL Server. Now we will execute following query in two different compatibility mode and see its performance. (Note that my SQL Server instance is of version 2014). USE AdventureWorks2014 GO -- ------------------------------- -- NEW Cardinality Estimation ALTER DATABASE AdventureWorks2014 SET COMPATIBILITY_LEVEL = 120 GO EXEC [dbo].[uspGetManagerEmployees] 44 GO -- ------------------------------- -- Old Cardinality Estimation ALTER DATABASE AdventureWorks2014 SET COMPATIBILITY_LEVEL = 110 GO EXEC [dbo].[uspGetManagerEmployees] 44 GO Result of Statistics IO Compatibility level 120 Table ‘Person’. Scan count 0, logical reads 6, physical reads 0, read-ahead reads 0, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0. Table ‘Employee’. Scan count 2, logical reads 7, physical reads 0, read-ahead reads 0, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0. Table ‘Worktable’. Scan count 0, logical reads 0, physical reads 0, read-ahead reads 0, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0. Table ‘Worktable’. Scan count 2, logical reads 7, physical reads 0, read-ahead reads 0, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0. Compatibility level 110 Table ‘Worktable’. Scan count 2, logical reads 7, physical reads 0, read-ahead reads 0, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0. Table ‘Person’. Scan count 0, logical reads 137, physical reads 0, read-ahead reads 0, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0. Table ‘Employee’. Scan count 2, logical reads 7, physical reads 0, read-ahead reads 0, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0. Table ‘Worktable’. Scan count 0, logical reads 0, physical reads 0, read-ahead reads 0, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0. You will notice in the case of compatibility level 110 there 137 logical read from table person where as in the case of compatibility level 120 there are only 6 physical reads from table person. This drastically improves the performance of the query. If we enable execution plan, we can see the same as well. I hope you will find this quick example helpful. You can read more about this in my latest Pluralsight Course. Reference: Pinal Dave (http://blog.SQLAuthority.com)Filed under: PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL

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  • JustMock is here !!

    - by mehfuzh
    As announced earlier by Hristo Kosev at Telerik blogs , we have started giving out JustMock builds from today. This is the first of early builds before the official Q2 release and we are pretty excited to get your feedbacks. Its pretty early to say anything on it. It actually depends on your feedback. To add few, with JustMock we tried to build a mocking tool with simple and intuitive syntax as possible excluding more and more noises and avoiding any smell that can be made to your code [We are still trying everyday] and we want to make the tool even better with your help. JustMock can be used to mock virtually anything. Moreover, we left an option open that it can be used to reduce / elevate the features  just though a single click. We tried to make a strong API and make stuffs fluent and guided as possible so that you never have the chance to get de-railed. Our syntax is AAA (Arrange – Act – Assert) , we don’t believe in Record – Reply model which some of the smarter mocking tools are planning to remove from their coming release or even don’t have [its always fun to lean from each other]. Overall more signals equals more complexity , reminds me of 37 signals :-). Currently, here are the things you can do with JustMock ( will cover more in-depth in coming days) Proxied mode Mock interfaces and class with virtuals Mock properties that includes indexers Set raise event for specific calls Use matchers to control mock arguments Assert specific occurrence of a mocked calls. Assert using matchers Do recursive mocks Do Sequential mocking ( same method with argument returns different values or perform different tasks) Do strict mocking (by default and i prefer loose , so that i can use it as stubs) Elevated mode Mock static calls Mock final class Mock sealed classes Mock Extension methods Partially mock a  class member directly using Mock.Arrange Mock MsCorlib (we will support more and more members in coming days) , currently we support FileInfo, File and DateTime. These are few, you need to take a look at the test project that is provided with the build to find more [Along with the document]. Also, one of feature that will i will be using it for my next OS projects is the ability to run it separately in  proxied mode which makes it easy to redistribute and do some personal development in a more DI model and my option to elevate as it go.   I’ve surely forgotten tons of other features to mention that i will cover time but  don’t for get the URL : www.telerik.com/justmock   Finally a little mock code:   var lvMock = Mock.Create<ILoveJustMock>();    // set your goal  Mock.Arrange(() => lvMock.Response(Arg.Any<string>())).Returns((int result) => result);    //perform  string ret =  lvMock.Echo("Yes");    Assert.Equal(ret, "Yes");  // make sure everything is fine  Mock.Assert(() => lvMock.Echo("Yes"), Occurs.Once());   Hope that helps to get started,  will cover if not :-).

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  • Merge sort versus quick sort performance

    - by Giorgio
    I have implemented merge sort and quick sort using C (GCC 4.4.3 on Ubuntu 10.04 running on a 4 GB RAM laptop with an Intel DUO CPU at 2GHz) and I wanted to compare the performance of the two algorithms. The prototypes of the sorting functions are: void merge_sort(const char **lines, int start, int end); void quick_sort(const char **lines, int start, int end); i.e. both take an array of pointers to strings and sort the elements with index i : start <= i <= end. I have produced some files containing random strings with length on average 4.5 characters. The test files range from 100 lines to 10000000 lines. I was a bit surprised by the results because, even though I know that merge sort has complexity O(n log(n)) while quick sort is O(n^2), I have often read that on average quick sort should be as fast as merge sort. However, my results are the following. Up to 10000 strings, both algorithms perform equally well. For 10000 strings, both require about 0.007 seconds. For 100000 strings, merge sort is slightly faster with 0.095 s against 0.121 s. For 1000000 strings merge sort takes 1.287 s against 5.233 s of quick sort. For 5000000 strings merge sort takes 7.582 s against 118.240 s of quick sort. For 10000000 strings merge sort takes 16.305 s against 1202.918 s of quick sort. So my question is: are my results as expected, meaning that quick sort is comparable in speed to merge sort for small inputs but, as the size of the input data grows, the fact that its complexity is quadratic will become evident? Here is a sketch of what I did. In the merge sort implementation, the partitioning consists in calling merge sort recursively, i.e. merge_sort(lines, start, (start + end) / 2); merge_sort(lines, 1 + (start + end) / 2, end); Merging of the two sorted sub-array is performed by reading the data from the array lines and writing it to a global temporary array of pointers (this global array is allocate only once). After each merge the pointers are copied back to the original array. So the strings are stored once but I need twice as much memory for the pointers. For quick sort, the partition function chooses the last element of the array to sort as the pivot and scans the previous elements in one loop. After it has produced a partition of the type start ... {elements <= pivot} ... pivotIndex ... {elements > pivot} ... end it calls itself recursively: quick_sort(lines, start, pivotIndex - 1); quick_sort(lines, pivotIndex + 1, end); Note that this quick sort implementation sorts the array in-place and does not require additional memory, therefore it is more memory efficient than the merge sort implementation. So my question is: is there a better way to implement quick sort that is worthwhile trying out? If I improve the quick sort implementation and perform more tests on different data sets (computing the average of the running times on different data sets) can I expect a better performance of quick sort wrt merge sort? EDIT Thank you for your answers. My implementation is in-place and is based on the pseudo-code I have found on wikipedia in Section In-place version: function partition(array, 'left', 'right', 'pivotIndex') where I choose the last element in the range to be sorted as a pivot, i.e. pivotIndex := right. I have checked the code over and over again and it seems correct to me. In order to rule out the case that I am using the wrong implementation I have uploaded the source code on github (in case you would like to take a look at it). Your answers seem to suggest that I am using the wrong test data. I will look into it and try out different test data sets. I will report as soon as I have some results.

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  • Speeding up procedural texture generation

    - by FalconNL
    Recently I've begun working on a game that takes place in a procedurally generated solar system. After a bit of a learning curve (having neither worked with Scala, OpenGL 2 ES or Libgdx before), I have a basic tech demo going where you spin around a single procedurally textured planet: The problem I'm running into is the performance of the texture generation. A quick overview of what I'm doing: a planet is a cube that has been deformed to a sphere. To each side, a n x n (e.g. 256 x 256) texture is applied, which are bundled in one 8n x n texture that is sent to the fragment shader. The last two spaces are not used, they're only there to make sure the width is a power of 2. The texture is currently generated on the CPU, using the updated 2012 version of the simplex noise algorithm linked to in the paper 'Simplex noise demystified'. The scene I'm using to test the algorithm contains two spheres: the planet and the background. Both use a greyscale texture consisting of six octaves of 3D simplex noise, so for example if we choose 128x128 as the texture size there are 128 x 128 x 6 x 2 x 6 = about 1.2 million calls to the noise function. The closest you will get to the planet is about what's shown in the screenshot and since the game's target resolution is 1280x720 that means I'd prefer to use 512x512 textures. Combine that with the fact the actual textures will of course be more complicated than basic noise (There will be a day and night texture, blended in the fragment shader based on sunlight, and a specular mask. I need noise for continents, terrain color variation, clouds, city lights, etc.) and we're looking at something like 512 x 512 x 6 x 3 x 15 = 70 million noise calls for the planet alone. In the final game, there will be activities when traveling between planets, so a wait of 5 or 10 seconds, possibly 20, would be acceptable since I can calculate the texture in the background while traveling, though obviously the faster the better. Getting back to our test scene, performance on my PC isn't too terrible, though still too slow considering the final result is going to be about 60 times worse: 128x128 : 0.1s 256x256 : 0.4s 512x512 : 1.7s This is after I moved all performance-critical code to Java, since trying to do so in Scala was a lot worse. Running this on my phone (a Samsung Galaxy S3), however, produces a more problematic result: 128x128 : 2s 256x256 : 7s 512x512 : 29s Already far too long, and that's not even factoring in the fact that it'll be minutes instead of seconds in the final version. Clearly something needs to be done. Personally, I see a few potential avenues, though I'm not particularly keen on any of them yet: Don't precalculate the textures, but let the fragment shader calculate everything. Probably not feasible, because at one point I had the background as a fullscreen quad with a pixel shader and I got about 1 fps on my phone. Use the GPU to render the texture once, store it and use the stored texture from then on. Upside: might be faster than doing it on the CPU since the GPU is supposed to be faster at floating point calculations. Downside: effects that cannot (easily) be expressed as functions of simplex noise (e.g. gas planet vortices, moon craters, etc.) are a lot more difficult to code in GLSL than in Scala/Java. Calculate a large amount of noise textures and ship them with the application. I'd like to avoid this if at all possible. Lower the resolution. Buys me a 4x performance gain, which isn't really enough plus I lose a lot of quality. Find a faster noise algorithm. If anyone has one I'm all ears, but simplex is already supposed to be faster than perlin. Adopt a pixel art style, allowing for lower resolution textures and fewer noise octaves. While I originally envisioned the game in this style, I've come to prefer the realistic approach. I'm doing something wrong and the performance should already be one or two orders of magnitude better. If this is the case, please let me know. If anyone has any suggestions, tips, workarounds, or other comments regarding this problem I'd love to hear them.

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  • SQL SERVER – Basic Calculation and PEMDAS Order of Operation

    - by pinaldave
    After thinking a long time, I have decided to write about this blog post. I had no plan to create a blog post about this subject but the amount of conversation this one has created on my Facebook page, I decided to bring up a few of the question and concerns discussed on the Facebook page. There are more than 10,000 comments here so far. There are lots of discussion about what should be the answer. Well, as far as I can tell there is a big debate going on on Facebook, for educational purpose you should go ahead and read some of the comments. They are very interesting and for sure teach some new stuff. Even though some of the comments are clearly wrong they have made some good points and I believe it for sure develops some logic. Here is my take on this subject. I believe the answer is 9 as I follow PEMDAS  Order of Operation. PEMDAS stands for  parentheses, exponents, multiplication, division, addition, subtraction. PEMDAS is commonly known as BODMAS in India. BODMAS stands for Brackets, Orders (ie Powers and Square Roots, etc), Division, Multiplication,  Addition and Subtraction. PEMDAS and BODMAS are almost same and both of them follow the operation order from LEFT to RIGHT. Let us try to simplify above statement using the PEMDAS or BODMAS (whatever you prefer to call). Step 1: 6 ÷ 2 (1+2) (parentheses first) Step 2: = 6 ÷ 2 * (1+2) (adding multiplication sign for further clarification) Step 3: = 6 ÷ 2* (3) (single digit in parentheses – simplify using operator) Step 4: = 6 ÷ 2 * 3 (Remember next Operation should be LEFT to RIGHT) Step 5: = 3 * 3 (because 6 ÷ 2 = 3; remember LEFT to RIGHT) Step 6: = 9 (final answer) Some often find Step 4 confusing and often ended up multiplying 2 and 3 resulting Step 5 to be 6 ÷ 6, this is incorrect because in this case we did not follow the order of LEFT to RIGHT. When we do not follow the order of operation from LEFT to RIGHT we end up with the answer 1 which is incorrect. Let us see what SQL Server returns as a result. I executed following statement in SQL Server Management Studio SELECT 6/2*(1+2) It is clear that SQL Server also thinks that the answer should be 9. Let us go ahead and ask Google what will be the answer of above question in Google I have searched for the following term: 6/2(1+2) The result also says the answer should be 9. If you want a further reference here is a great video which describes why the answer should be 9 and not 1. And here is a fantastic conversation on Google Groups. Well, now what is your take on this subject? You are welcome to share constructive feedback and your answer may be different from my answer. NOTE: A healthy conversation about this subject is indeed encouraged but if there is a single bad word or comment is flaming it will be deleted without any notification (it does not matter how valuable information it contains). Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: About Me, PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

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