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• How to choose my own filename format for subscribed podcast files?

  - by meomaxy

  I subscribe to several podcasts where the filenames of the downloaded mp3 files have no particular pattern to them. When I copy the directory of accumulated mp3 files into my mp3 player, the files play in alphabetical order. What I really want is to play the files chronologically by release date. I currently use iTunes on Windows XP to download the files. What I do now is manually rename the files, adding the date in YYYYMMDD format to the start of each filename so that an alphabetical listing of files will correspond to their chronological order when I listen to them later in PocketTunes on my Palm Centro. Is there some way to get the release date into the filename automatically? If so, I could automate or possibly skip the file renaming step. I would switch from iTunes to something else if that would solve my problem. The file creation time on my local disk isn't a reliable indicator because sometimes I download a few days worth of content at one time, and the files don't necessarily get downloaded in chronological order.

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• SOA Starting Point: Methods for Service Identification and Definition

  As more and more companies start to incorporate a Service Oriented Architectural design approach into their existing enterprise systems, it creates the need for a standardized integration technology. One common technology used by companies is an Enterprise Service Bus (ESB). An ESB, as defined by Progress Software, connects and mediates all communications and interactions between services. In essence an ESB is a form of middleware that allows services to communicate with one another regardless of framework, environment, or location. With the emergence of ESB, a new emphasis is now being placed on approaches that can be used to determine what Web services should be built. In addition, what order should these services be built? In May 2011, SOA Magazine published an article that identified 10 common methods for identifying and defining services. SOA’s Ten Common Methods for Service Identification and Definition: Business Process Decomposition Business Functions Business Entity Objects Ownership and Responsibility Goal-Driven Component-Based Existing Supply (Bottom-Up) Front-Office Application Usage Analysis Infrastructure Non-Functional Requirements  Each of these methods provides various pros and cons in regards to their use within the design process. I personally feel that during a design process, multiple methodologies should be used in order to accurately define a design for a system or enterprise system. Personally, I like to create a custom cocktail derived from combining these methodologies in order to ensure that my design fits with the project’s and business’s needs while still following development standards and guidelines. Of these ten methods, I am particularly fond of Business Process Decomposition, Business Functions, Goal-Driven, Component-Based, and routinely use them in my designs.  Works Cited Hubbers, J.-W., Ligthart, A., & Terlouw , L. (2007, 12 10). Ten Ways to Identify Services. Retrieved from SOA Magazine: http://www.soamag.com/I13/1207-1.php Progress.com. (2011, 10 30). ESB ARCHITECTURE AND LIFECYCLE DEFINITION. Retrieved from Progress.com: http://web.progress.com/en/esb-architecture-lifecycle-definition.html

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• Is there a way to sort my windows within a screen session?

  - by jv1975

  I use screen and have ssh sessions open to a number of different machines from within my screen session. I'd like to keep them in order, for obvious reasons. Often I'll have to connect to a new machine which alphabetically/numerically should fit in between two existing windows. I can't find any way to reorder the windows other than with the "number" command, which swaps my current window with that at the number I specified. So adding a new window to the 15 I already have and then sticking it at position 2, while keeping all the other windows in order as well is cumbersome, to say the least, requiring swaps for all windows past #2. Is there anyway to sort the windows alphabetically? Or a way to "shift" all windows after a certain point up one spot? Or any other suggestions to insert a new window at an arbitrary point while still maintaining the order of all other windows? Thanks!

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• What is the `ServerName` attribute for apache2 and what does it do?

  - by freddydoggie

  I do not know what this config setting means. Does it mean that it registers a domain name? Is it like DNS? Here is what I have for my apache2 default config ServerName staugie.org ServerAdmin webmaster@localhost DocumentRoot /var/www <Directory /> Options FollowSymLinks Indexes MultiViews AllowOverride All </Directory> <Directory /var/www/> Options Indexes FollowSymLinks MultiViews AllowOverride All Order allow,deny allow from all </Directory> ScriptAlias /cgi-bin/ /usr/lib/cgi-bin/ <Directory "/usr/lib/cgi-bin"> AllowOverride All Options +ExecCGI -MultiViews +SymLinksIfOwnerMatch Order allow,deny Allow from all </Directory> ErrorLog ${APACHE_LOG_DIR}/error.log # Possible values include: debug, info, notice, warn, error, crit, # alert, emerg. LogLevel warn CustomLog ${APACHE_LOG_DIR}/access.log combined Alias /doc/ "/usr/share/doc/" <Directory "/usr/share/doc/"> Options Indexes MultiViews FollowSymLinks AllowOverride None Order deny,allow Deny from all Allow from 127.0.0.0/255.0.0.0 ::1/128 </Directory> also, is there any way to register a free domain through the apache foundation?

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• How to integrate a PHP CMS with paypal so that only users who completed a payment can register and authenticate?

  - by ibiza

  I am currently using a PHP CMS - cmsmadesimple - in order to create a website where services will be sold. I intend to use Paypal 'Buy Now' buttons in order to offer a few packages that will be renewable every 1-month or every 3-months and that grant access to the secure content of the website for a given period of time. Everything is going well so far but I am somewhat at loss for the user registration process as I have a few constraints I would like to use and it would be nice to automate the process if possible. Here are the constraints : User should be able to register to my website and choose a password himself Only users that paid should be able to register Access permissions should be disabled automatically after the service period if the package is not renewed And here is the process which I am thinking of : User clicks 'buy' on my website User is redirected on Paypal and completes the payment The paypal email used to pay should be returned to my server and somehow stored If it is a new email, user needs to register to my website (else if it is a returning customer, the deactivation flag for payment stopped should be removed to give back access) If a user does not renew his subscription, there should be a deactivation flag automatically set to the email used in order to lock access until next payment. Ideally, no human intervention is needed. What is the best way to implement all this? I am a bit at loss. I found this article that explained a few things and even has a nice code snippet, except that I'm not sure where to plug it. Thanks all

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• Another VSeWSS Error Resolved (List Template not installed on Farm)

  - by Damon

  Ran into a minor snag today trying to deploy a project with VSeWSS 1.3 - during the deployment it gave me the following error: Error    32    VSeWSS Service Error: Feature '2ade6552-200e-4425-8af5-f1f50c115b7e' for list template '10001' is not installed in this farm.  The operation could not be completed. At first glance, it looked my features were not installing in the correct order because the solution was installing a list that required a custom list definition before the custom list definition was being installed.  After switching the order in the WSP view (View -> Other Windows -> WSP View) -- you can use the up and down arrows on the view pane to switch feature installation order - I had the same error. I decided to try deleting the list, but upon visiting the list in the web interface I received a similar error about how the feature was not installed on the farm.  As such, I could not delete the list through the web interface.  Fortunately, the stsadm.exe tool worked just fine: stsadm.exe -o forcedeletelist -url <urltolisthere>

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• Database Migration Scripts: Getting from place A to place B

  - by Phil Factor

  We’ll be looking at a typical database ‘migration’ script which uses an unusual technique to migrate existing ‘de-normalised’ data into a more correct form. So, the book-distribution business that uses the PUBS database has gradually grown organically, and has slipped into ‘de-normalisation’ habits. What’s this? A new column with a list of tags or ‘types’ assigned to books. Because books aren’t really in just one category, someone has ‘cured’ the mismatch between the database and the business requirements. This is fine, but it is now proving difficult for their new website that allows searches by tags. Any request for history book really has to look in the entire list of associated tags rather than the ‘Type’ field that only keeps the primary tag. We have other problems. The TypleList column has duplicates in there which will be affecting the reporting, and there is the danger of mis-spellings getting there. The reporting system can’t be persuaded to do reports based on the tags and the Database developers are complaining about the unCoddly things going on in their database. In your version of PUBS, this extra column doesn’t exist, so we’ve added it and put in 10,000 titles using SQL Data Generator. /* So how do we refactor this database? firstly, we create a table of all the tags. */IF  OBJECT_ID('TagName') IS NULL OR OBJECT_ID('TagTitle') IS NULL  BEGIN  CREATE TABLE  TagName (TagName_ID INT IDENTITY(1,1) PRIMARY KEY ,     Tag VARCHAR(20) NOT NULL UNIQUE)  /* ...and we insert into it all the tags from the list (remembering to take out any leading spaces */  INSERT INTO TagName (Tag)     SELECT DISTINCT LTRIM(x.y.value('.', 'Varchar(80)')) AS [Tag]     FROM     (SELECT  Title_ID,          CONVERT(XML, '<list><i>' + REPLACE(TypeList, ',', '</i><i>') + '</i></list>')          AS XMLkeywords          FROM   dbo.titles)g    CROSS APPLY XMLkeywords.nodes('/list/i/text()') AS x ( y )  /* we can then use this table to provide a table that relates tags to articles */  CREATE TABLE TagTitle   (TagTitle_ID INT IDENTITY(1, 1),   [title_id] [dbo].[tid] NOT NULL REFERENCES titles (Title_ID),   TagName_ID INT NOT NULL REFERENCES TagName (Tagname_ID)   CONSTRAINT [PK_TagTitle]       PRIMARY KEY CLUSTERED ([title_id] ASC, TagName_ID)       ON [PRIMARY])        CREATE NONCLUSTERED INDEX idxTagName_ID  ON  TagTitle (TagName_ID)  INCLUDE (TagTitle_ID,title_id)        /* ...and it is easy to fill this with the tags for each title ... */        INSERT INTO TagTitle (Title_ID, TagName_ID)    SELECT DISTINCT Title_ID, TagName_ID      FROM        (SELECT  Title_ID,          CONVERT(XML, '<list><i>' + REPLACE(TypeList, ',', '</i><i>') + '</i></list>')          AS XMLkeywords          FROM   dbo.titles)g    CROSS APPLY XMLkeywords.nodes('/list/i/text()') AS x ( y )    INNER JOIN TagName ON TagName.Tag=LTRIM(x.y.value('.', 'Varchar(80)'))    END    /* That's all there was to it. Now we can select all titles that have the military tag, just to try things out */SELECT Title FROM titles  INNER JOIN TagTitle ON titles.title_ID=TagTitle.Title_ID  INNER JOIN Tagname ON Tagname.TagName_ID=TagTitle.TagName_ID  WHERE tagname.tag='Military'/* and see the top ten most popular tags for titles */SELECT Tag, COUNT(*) FROM titles  INNER JOIN TagTitle ON titles.title_ID=TagTitle.Title_ID  INNER JOIN Tagname ON Tagname.TagName_ID=TagTitle.TagName_ID  GROUP BY Tag ORDER BY COUNT(*) DESC/* and if you still want your list of tags for each title, then here they are */SELECT title_ID, title, STUFF(  (SELECT ','+tagname.tag FROM titles thisTitle    INNER JOIN TagTitle ON titles.title_ID=TagTitle.Title_ID    INNER JOIN Tagname ON Tagname.TagName_ID=TagTitle.TagName_ID  WHERE ThisTitle.title_id=titles.title_ID  FOR XML PATH(''), TYPE).value('.', 'varchar(max)')  ,1,1,'')    FROM titles  ORDER BY title_ID So we’ve refactored our PUBS database without pain. We’ve even put in a check to prevent it being re-run once the new tables are created. Here is the diagram of the new tag relationship We’ve done both the DDL to create the tables and their associated components, and the DML to put the data in them. I could have also included the script to remove the de-normalised TypeList column, but I’d do a whole lot of tests first before doing that. Yes, I’ve left out the assertion tests too, which should check the edge cases and make sure the result is what you’d expect. One thing I can’t quite figure out is how to deal with an ordered list using this simple XML-based technique. We can ensure that, if we have to produce a list of tags, we can get the primary ‘type’ to be first in the list, but what if the entire order is significant? Thank goodness it isn’t in this case. If it were, we might have to revisit a string-splitter function that returns the ordinal position of each component in the sequence. You’ll see immediately that we can create a synchronisation script for deployment from a comparison tool such as SQL Compare, to change the schema (DDL). On the other hand, no tool could do the DML to stuff the data into the new table, since there is no way that any tool will be able to work out where the data should go. We used some pretty hairy code to deal with a slightly untypical problem. We would have to do this migration by hand, and it has to go into source control as a batch. If most of your database changes are to be deployed by an automated process, then there must be a way of over-riding this part of the data synchronisation process to do this part of the process taking the part of the script that fills the tables, Checking that the tables have not already been filled, and executing it as part of the transaction. Of course, you might prefer the approach I’ve taken with the script of creating the tables in the same batch as the data conversion process, and then using the presence of the tables to prevent the script from being re-run. The problem with scripting a refactoring change to a database is that it has to work both ways. If we install the new system and then have to rollback the changes, several books may have been added, or had their tags changed, in the meantime. Yes, you have to script any rollback! These have to be mercilessly tested, and put in source control just in case of the rollback of a deployment after it has been in place for any length of time. I’ve shown you how to do this with the part of the script .. /* and if you still want your list of tags for each title, then here they are */SELECT title_ID, title, STUFF(  (SELECT ','+tagname.tag FROM titles thisTitle    INNER JOIN TagTitle ON titles.title_ID=TagTitle.Title_ID    INNER JOIN Tagname ON Tagname.TagName_ID=TagTitle.TagName_ID  WHERE ThisTitle.title_id=titles.title_ID  FOR XML PATH(''), TYPE).value('.', 'varchar(max)')  ,1,1,'')    FROM titles  ORDER BY title_ID …which would be turned into an UPDATE … FROM script. UPDATE titles SET  typelist= ThisTaglistFROM     (SELECT title_ID, title, STUFF(    (SELECT ','+tagname.tag FROM titles thisTitle      INNER JOIN TagTitle ON titles.title_ID=TagTitle.Title_ID      INNER JOIN Tagname ON Tagname.TagName_ID=TagTitle.TagName_ID    WHERE ThisTitle.title_id=titles.title_ID    ORDER BY CASE WHEN tagname.tag=titles.[type] THEN 1 ELSE 0  END DESC    FOR XML PATH(''), TYPE).value('.', 'varchar(max)')    ,1,1,'')  AS ThisTagList  FROM titles)fINNER JOIN Titles ON f.title_ID=Titles.title_ID You’ll notice that it isn’t quite a round trip because the tags are in a different order, though we’ve managed to make sure that the primary tag is the first one as originally. So, we’ve improved the database for the poor book distributors using PUBS. It is not a major deal but you’ve got to be prepared to provide a migration script that will go both forwards and backwards. Ideally, database refactoring scripts should be able to go from any version to any other. Schema synchronization scripts can do this pretty easily, but no data synchronisation scripts can deal with serious refactoring jobs without the developers being able to specify how to deal with cases like this.

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• Is there any way to send a column value from outer query to inner sub query? [closed]

  - by chetan

  'Discussions' table schema title description desid replyto upvote downvote views browser used a1 none 1 1 12 - bad topic b2 a1 2 3 14 sql database a3 none 4 5 34 - crome b4 a3 3 4 12 The above table has two types of content types Main Topics and Comments. Unique content identifier 'desid' used to identify that its a main topic or a comment. 'desid' starts with 'a' for Main Topic and for comment 'desid' starts with 'b'. For comment 'replyto' is the 'desid' of main topic to which this comment is associated. I like to find out the list of the top main topics that are arranged on the basis of (upvote+downvote+visits+number of comments to it) addition. The following query gives top topics list in order of (upvote+downvote+visits) select * with highest number of upvote+downvote+views by query "select * from [DB_user1212].[dbo].[discussions] where desid like 'a%' order by (upvote+downvote+visited) desc For (comments+upvote+downvote+views ) I tried select * from [DB_user1212].[dbo].[discussions] where desid like 'a%' order by ((select count(*) from [DB_user1212].[dbo].[discussions] where replyto = desid )+upvote+downvote+visited) desc but it didn't work because its not possible to send desid from outer query to inner subquery. How to solve this? Please note that I want solution in query language only.

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• Customer Experience Management for Retail 2.0 - part 2 / 2

  - by Sanjeev Sharma

  In the previous post, i discussed some of the key trends shaping up in the retail industry, their implications and the challenges facing retailers seeking to regain control of the buyer-seller relationship. Is Customer Experience Management the panacea for the ailing retailers who are now awakening to the power of the consumer? Quite honestly, customer acquisition, retention and satisfaction have been top of mind for retailers for quite some time now. The missing piece of this puzzle is bringing all those countless hours of strategy and planning to fruition. This is more of an execution gap than anything else. Although technology has made consumers more informed, more mobile and more social, customer experience is still largely defined by delivering on the following: Consistent experiences, whether shopping online or offline Personalize-able interaction ("mass market" sounds good as an internal strategy but not when you are a buyer!) Timely order fulfillment, if not pro-active notification of delays Below is a concept architecture for streamlining front-end, mid-office and back-end interfaces through shared process to achieve consistency and efficiency in managing the customer experience from order capture to order provisioning.

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• T-SQL select where and group by date

  - by bconlon

  T-SQL has never been my favorite language, but I need to use it on a fairly regular basis and every time I seem to Google the same things. So if I add it here, it might help others with the same issues, but it will also save me time later as I will know where to look for the answers!! 1. How do I SELECT FROM WHERE to filter on a DateTime column? As it happens this is easy but I always forget. You just put the DATE value in single quotes and in standard format: SELECT StartDate FROM Customer WHERE StartDate >= '2011-01-01' ORDER BY StartDate 2. How do I then GROUP BY and get a count by StartDate? Bit trickier, but you can use the built in DATEADD and DATEDIFF to set the TIME part to midnight, allowing the GROUP BY to have a consistent value to work on: SELECT DATEADD (d, DATEDIFF(d, 0, StartDate),0) [Customer Creation Date], COUNT(*) [Number Of New Customers] FROM Customer WHERE StartDate >= '2011-01-01' GROUP BY DATEADD(d, DATEDIFF(d, 0, StartDate),0) ORDER BY [Customer Creation Date] Note: [Customer Creation Date] and [Number Of New Customers] column alias just provide more readable column headers. 3. Finally, how can you format the DATETIME to only show the DATE part (after all the TIME part is now always midnight)? The built in CONVERT function allows you to convert the DATETIME to a CHAR array using a specific format. The format is a bit arbitrary and needs looking up, but 101 is the U.S. standard mm/dd/yyyy, and 103 is the U.K. standard dd/mm/yyyy. SELECT CONVERT(CHAR(10), DATEADD(d, DATEDIFF(d, 0, StartDate),0), 103) [Customer Creation Date], COUNT(*) [Number Of New Customers] FROM Customer WHERE StartDate >= '2011-01-01' GROUP BY DATEADD(d, DATEDIFF(d, 0, StartDate),0) ORDER BY [Customer Creation Date]  #

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• Business Forces: SOA Adoption

  The only constant in today’s business environment is change. Businesses that continuously foresee change and adapt quickly will gain market share and increased growth. In our ever growing global business environment change is driven by data in regards to collecting, maintaining, verifying and distributing data.  Companies today are made and broken over data. Would anyone still use Google if they did not have one of the most accurate search indexes on the internet? No, because their value is in their data and the quality of their data. Due to the increasing focus on data, companies have been adopting new methodologies for gaining more control over their data while attempting to reduce the costs of maintaining it. In addition, companies are also trying to reduce the time it takes to analyze data in regards to various market forces to foresee changes prior to them actually occurring.   Benefits of Adopting SOA Services can be maintained separately from other services and applications so that a change in one service will only affect itself and client services or applications. The advent of services allows for system functionality to be distributed across a network or multiple networks. The costs associated with maintain business functionality is much higher in standard application development over SOA due to the fact that one Services can be maintained and shared to other applications instead of multiple instances of business functionality being duplicated via hard coding in to several applications. When multiple applications use a single service for a specific business function then the all of the data being processed will be consistent in terms of quality and accuracy through the applications. Disadvantages of Adopting SOA Increased initial costs and timelines are associated with SOA due to the fact that services need to be created as well as applications need to be modified to call the services In order for an SOA project to be successful the project must obtain company and management support in order to gain the proper exposure, funding, and attention. If SOA is new to a company they must also support the proper training in order for the project to be designed, and implemented correctly. References: Tews, R. (2007). Beyond IT: Exploring the Business Value of SOA. SOA Magazine Issue XI.

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• Mesh with Alpha Texture doesn't blend properly

  - by faulty

  I've followed example from various place regarding setting OutputMerger's BlendState to enable alpha/transparent texture on mesh. The setup is as follows: var transParentOp = new BlendStateDescription { SourceBlend = BlendOption.SourceAlpha, DestinationBlend = BlendOption.InverseDestinationAlpha, BlendOperation = BlendOperation.Add, SourceAlphaBlend = BlendOption.Zero, DestinationAlphaBlend = BlendOption.Zero, AlphaBlendOperation = BlendOperation.Add, }; I've made up a sample that display 3 mesh A, B and C, where each overlaps one another. They are drawn sequentially, A to C. Distance from camera where A is nearest and C is furthest. So, the expected output is that A see through and saw part of B and C. B will see through and saw part of C. But what I get was none of them see through in that order, but if I move C closer to the camera, then it will be semi transparent and see through A and B. B if move closer to camera will see A but not C. Sort of reverse. So it seems that I need to draw them in reverse order where furthest from camera is drawn first then nearest to camera is drawn last. Is it suppose to be done this way, or I can actually configure the blendstate so it works no matter in which order i draw them? Thanks

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• Only allow the POST method for a specific file in a directory

  - by Dave Chen

  I have one file that should only be accessible via the POST method. /var/www/folder/index.php The document root is /var/www/ and index.php is nested inside a folder. My configurations are as follows: <Directory "/var/www/folder"> <Files "index.php"> order deny,allow Allow from all <LimitExcept POST> Deny from all </LimitExcept> </Files> </Directory> I visit my server at 127.0.0.1/folder but I can GET and POST the file just like normal. I've also tried reversing the order, order allow,deny, require, limitexcept and limit. How can I only allow POST requests to be processed by one file in a folder?

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• How can state changes be batched while adhering to opaque-front-to-back/alpha-blended-back-to-front?

  - by Sion Sheevok

  This is a question I've never been able to find the answer to. Batching objects with similar states is a major performance gain when rendering many objects. However, I've been learned various rules when drawing objects in the game world. Draw all opaque objects, front-to-back. Draw all alpha-blended objects, back-to-front. Some of the major parameters to batch by, as I understand it, are textures, vertex buffers, and index buffers. It seems that, as long as you are adhering to the above two rules, there's little to be done in regards to batching. I see one possibility to batch, while still adhering to the above two rules. Opaque objects can still be drawn out of depth-order, because drawing them front-to-back is merely a fillrate optimization, meanwhile state changes may very well be far more expensive than the overdraw of drawing out of depth-order. However, non-opaque objects, those that require alpha-blending at least, must be drawn back-to-front in order to avoid rendering artifacts. Is the loss of the fillrate optimization for opaques worth the state batching optimization?

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• Do cross reference database tables have a place in domain driven design?

  - by Mike Cellini

  First some background. Let's say we have a system where a customer is placing an order in a web interface. The items that customer is ordering can priced in various ways. Sometimes including the cost of delivery and sometimes not at all. That pricing effectively depends on a variety of factors including the vendor's own pricing model, that vendor's individual contracts with customers as well as that vendor's contracts with its own suppliers. Let's assume that once a customer places an order for a particular item and chooses a contract if any, the method of delivery can be determined by variables on those contracts. Those delivery methods also live in their own table in the database and have various properties consumed downstream. It makes sense that a cross reference or lookup table would store that information. That table would be loaded into the domain and could then be used to apply the appropriate delivery method while processing the order. Does this make sense in the context of domain driven design? Or is my thinking too relational? Is this logic that should be built into it's own class/method (I mean beyond apply the cross reference table data)?

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• Tail-recursive implementation of take-while

  - by Giorgio

  I am trying to write a tail-recursive implementation of the function take-while in Scheme (but this exercise can be done in another language as well). My first attempt was (define (take-while p xs) (if (or (null? xs) (not (p (car xs)))) '() (cons (car xs) (take-while p (cdr xs))))) which works correctly but is not tail-recursive. My next attempt was (define (take-while-tr p xs) (let loop ((acc '()) (ys xs)) (if (or (null? ys) (not (p (car ys)))) (reverse acc) (loop (cons (car ys) acc) (cdr ys))))) which is tail recursive but needs a call to reverse as a last step in order to return the result list in the proper order. I cannot come up with a solution that is tail-recursive, does not use reverse, only uses lists as data structure (using a functional data structure like a Haskell's sequence which allows to append elements is not an option), has complexity linear in the size of the prefix, or at least does not have quadratic complexity (thanks to delnan for pointing this out). Is there an alternative solution satisfying all the properties above? My intuition tells me that it is impossible to accumulate the prefix of a list in a tail-recursive fashion while maintaining the original order between the elements (i.e. without the need of using reverse to adjust the result) but I am not able to prove this. Note The solution using reverse satisfies conditions 1, 3, 4.

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• Faster Memory Allocation Using vmtasks

  - by Steve Sistare

  You may have noticed a new system process called "vmtasks" on Solaris 11 systems: % pgrep vmtasks 8 % prstat -p 8 PID USERNAME SIZE RSS STATE PRI NICE TIME CPU PROCESS/NLWP 8 root 0K 0K sleep 99 -20 9:10:59 0.0% vmtasks/32 What is vmtasks, and why should you care? In a nutshell, vmtasks accelerates creation, locking, and destruction of pages in shared memory segments. This is particularly helpful for locked memory, as creating a page of physical memory is much more expensive than creating a page of virtual memory. For example, an ISM segment (shmflag & SHM_SHARE_MMU) is locked in memory on the first shmat() call, and a DISM segment (shmflg & SHM_PAGEABLE) is locked using mlock() or memcntl(). Segment operations such as creation and locking are typically single threaded, performed by the thread making the system call. In many applications, the size of a shared memory segment is a large fraction of total physical memory, and the single-threaded initialization is a scalability bottleneck which increases application startup time. To break the bottleneck, we apply parallel processing, harnessing the power of the additional CPUs that are always present on modern platforms. For sufficiently large segments, as many of 16 threads of vmtasks are employed to assist an application thread during creation, locking, and destruction operations. The segment is implicitly divided at page boundaries, and each thread is given a chunk of pages to process. The per-page processing time can vary, so for dynamic load balancing, the number of chunks is greater than the number of threads, and threads grab chunks dynamically as they finish their work. Because the threads modify a single application address space in compressed time interval, contention on locks protecting VM data structures locks was a problem, and we had to re-scale a number of VM locks to get good parallel efficiency. The vmtasks process has 1 thread per CPU and may accelerate multiple segment operations simultaneously, but each operation gets at most 16 helper threads to avoid monopolizing CPU resources. We may reconsider this limit in the future. Acceleration using vmtasks is enabled out of the box, with no tuning required, and works for all Solaris platform architectures (SPARC sun4u, SPARC sun4v, x86). The following tables show the time to create + lock + destroy a large segment, normalized as milliseconds per gigabyte, before and after the introduction of vmtasks: ISM system ncpu before after speedup ------ ---- ------ ----- ------- x4600 32 1386 245 6X X7560 64 1016 153 7X M9000 512 1196 206 6X T5240 128 2506 234 11X T4-2 128 1197 107 11x DISM system ncpu before after speedup ------ ---- ------ ----- ------- x4600 32 1582 265 6X X7560 64 1116 158 7X M9000 512 1165 152 8X T5240 128 2796 198 14X (I am missing the data for T4 DISM, for no good reason; it works fine). The following table separates the creation and destruction times: ISM, T4-2 before after ------ ----- create 702 64 destroy 495 43 To put this in perspective, consider creating a 512 GB ISM segment on T4-2. Creating the segment would take 6 minutes with the old code, and only 33 seconds with the new. If this is your Oracle SGA, you save over 5 minutes when starting the database, and you also save when shutting it down prior to a restart. Those minutes go directly to your bottom line for service availability.

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• How to choose my own filename format for subscribed podcast files?

  - by user14068

  I subscribe to several podcasts where the filenames of the downloaded mp3 files have no particular pattern to them. When I copy the directory of accumulated mp3 files into my mp3 player, the files play in alphabetical order. What I really want is to play the files chronologically by release date. I currently use iTunes on Windows XP to download the files. What I do now is manually rename the files, adding the date in YYYYMMDD format to the start of each filename so that an alphabetical listing of files will correspond to their chronological order when I listen to them later in PocketTunes on my Palm Centro. Is there some way to get the release date into the filename automatically? If so, I could automate or possibly skip the file renaming step. I would switch from iTunes to something else if that would solve my problem. The file creation time on my local disk isn't a reliable indicator because sometimes I download a few days worth of content at one time, and the files don't necessarily get downloaded in chronological order.

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• Using WKA in Large Coherence Clusters (Disabling Multicast)

  - by jpurdy

  Disabling hardware multicast (by configuring well-known addresses aka WKA) will place significant stress on the network. For messages that must be sent to multiple servers, rather than having a server send a single packet to the switch and having the switch broadcast that packet to the rest of the cluster, the server must send a packet to each of the other servers. While hardware varies significantly, consider that a server with a single gigabit connection can send at most ~70,000 packets per second. To continue with some concrete numbers, in a cluster with 500 members, that means that each server can send at most 140 cluster-wide messages per second. And if there are 10 cluster members on each physical machine, that number shrinks to 14 cluster-wide messages per second (or with only mild hyperbole, roughly zero). It is also important to keep in mind that network I/O is not only expensive in terms of the network itself, but also the consumption of CPU required to send (or receive) a message (due to things like copying the packet bytes, processing a interrupt, etc). Fortunately, Coherence is designed to rely primarily on point-to-point messages, but there are some features that are inherently one-to-many: Announcing the arrival or departure of a member Updating partition assignment maps across the cluster Creating or destroying a NamedCache Invalidating a cache entry from a large number of client-side near caches Distributing a filter-based request across the full set of cache servers (e.g. queries, aggregators and entry processors) Invoking clear() on a NamedCache The first few of these are operations that are primarily routed through a single senior member, and also occur infrequently, so they usually are not a primary consideration. There are cases, however, where the load from introducing new members can be substantial (to the point of destabilizing the cluster). Consider the case where cluster in the first paragraph grows from 500 members to 1000 members (holding the number of physical machines constant). During this period, there will be 500 new member introductions, each of which may consist of several cluster-wide operations (for the cluster membership itself as well as the partitioned cache services, replicated cache services, invocation services, management services, etc). Note that all of these introductions will route through that one senior member, which is sharing its network bandwidth with several other members (which will be communicating to a lesser degree with other members throughout this process). While each service may have a distinct senior member, there's a good chance during initial startup that a single member will be the senior for all services (if those services start on the senior before the second member joins the cluster). It's obvious that this could cause CPU and/or network starvation. In the current release of Coherence (3.7.1.3 as of this writing), the pure unicast code path also has less sophisticated flow-control for cluster-wide messages (compared to the multicast-enabled code path), which may also result in significant heap consumption on the senior member's JVM (from the message backlog). This is almost never a problem in practice, but with sufficient CPU or network starvation, it could become critical. For the non-operational concerns (near caches, queries, etc), the application itself will determine how much load is placed on the cluster. Applications intended for deployment in a pure unicast environment should be careful to avoid excessive dependence on these features. Even in an environment with multicast support, these operations may scale poorly since even with a constant request rate, the underlying workload will increase at roughly the same rate as the underlying resources are added. Unless there is an infrastructural requirement to the contrary, multicast should be enabled. If it can't be enabled, care should be taken to ensure the added overhead doesn't lead to performance or stability issues. This is particularly crucial in large clusters.

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• what to learn & practice to be a programmer (not for Job) [closed]

  - by Hanan N.

  I want to be able to write programs (tools) for my own needs, and I want to tell the computer what to do, not to be strict to what other's told it to do. I have a good knowledge of Linux & Windows, I am also have a bit of Python in my head, but I think that I need some guidance on what languages or practices to invest my time into in order to be able to tell the computer what to do. I know there is a lot of posts similar to what I am asking here, but there is a big difference and so I have opened this thread. My goal isn't to work at a company, so I don't need to learn how to work as a team, I don't need to learn as much how to maintain my code nor how to write it nice for others to understand (I know it is important but not for me). I don't want to learn it as a profession, but as a serious hobby (you can call it hacking as long as you know what cracking means), my end goal is to be able to understand other's people code, and to write my own code with a lot of deep knowledge of the ins and outs of the computer system in order to gain from it as much as I can. So in essence my questions are: How can I understand, in depth, computers, in order to exploit them as much as I can? What should I learn? Are there any books that I should read? Is it possible to do this, or do I have to learn every aspect of programming?

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• What is the 'cacert.pem' and for what to use that?

  - by user65567

  I am developing a web application on localhost with domains and sub-domains and I would like to use a HTTPS connection. On my Mac OS, in order to enable SSL, I need to set Apache correctly, so I followed some guide to accomplish part of that. Now it is time to choose a certificate in order to test HTTPS requests. I seen the cacert.pem, but I don't know how to use that and for what it is used (can you explain to me some about its usage?)... So, is it possible to use the cacert.pem (see the link) for all my domains and subdomains (maybe, as a wildcard certificate) on localhost? If so, how to do that? What certificate I have to take and use? If no, what I need to do in order to use a wildcard certificate for all my domains and subdomains on localhost? Of course those certificates must be accepted by browsers and working for HTTPS connection between my domains.

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• NHibernate, VS 2010

  - by ??????

  ????????????, ANRY! ?????? ??????? ??? ??????????? ???????? ?? ????????????, ?????????? ? NHibernate. ??? ?? ???????? ???? ?????? "Hello NHibernate!". ???????????? ??????????? ????? ??????? ????????: ?? ????, ???? ?????, ??????, ?????. ?????????????? ?????? 4 ??????? ? MSSQL 2010: ?????(id_??????, ????????, ????), ??????(id_???????, ???, ???????), ?????(id_??????, id_???????, ?????????) ? ?????? ??????(id_?????? ??????, id_??????, id_??????, ??????????). ??????????????, ?????? 4 ??????: ?????, ??????, ?????, ?????? ??????. ?????? ??? ?????: ????? ?? ????????? 4 mapping-?????, ??? ?? ????? ???????????? ?????? ? ????? ???? Debug ???????? ????????? ??????: "Could not compile the mapping document: Sklad.products.hbm.xml". ?????? "????????" ?????????, ??? ??????. ? ??? ????? ???? ???????? ? ??? ?? ????? ??????? ? ?????????, ??????. P.S. ???? ?? ??????, ?????? ???????? ?? ?????: [email protected] Google translation (I cleaned this up a but, don't don't speak russian, someone else please improve if it's wrong) Hello, ANRY! Most recently, during the passage of the practice of the university, faced with NHibernate. I read your article "Hello NHibernate!". Took to implement something like a store: that is, a product, the customer order. Accordingly created 4 tables in MSSQL 2010: Goods (id_tovara, name, price) Client (id_klienta, name, surname) Order (id_zakaza, id_klienta, cost) Order Line (id_stroki order id_zakaza, id_tovara, quantity) Accordingly, created 4 classes: Product, Customer, Order, Order Line. my question is this: whether you want to create 4 mapping-file, or you can make only one? And when there is a Debug gives the following error: "Could not compile the mapping document: Sklad.products.hbm.xml. And "Build" is normal, no errors. In what may be the problem and how it can solve? Regards, Andrew. PS if not difficult, you can reply to e-mail: [email protected]

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• Invoke a SOAP method with namespace prefixes

  - by mvladic

  My C# web service client sends following soap message to Java-based web service: <?xml version="1.0" encoding="utf-8"?> <soap:Envelope xmlns:soap="http://www.w3.org/2003/05/soap-envelope" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema"> <soap:Body> <getData> <request> <requestParameters xmlns="http://b..."> <equals> ... </equals> </requestParameters> </request> </getData> </soap:Body> </soap:Envelope> and Java-based web service returns error: 500 Internal Server Error ... Cannot find dispatch method for {}getData ... Client written in Java, which works, sends the following message: <?xml version="1.0" encoding="utf-8"?> <soap:Envelope xmlns:soap="http://www.w3.org/2003/05/soap-envelope" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema"> <soap:Body> <ns2:getData xmlns:ns2="http://a..."> <ns2:request> <ns3:requestParameters xmlns:ns3="http://b..."> <ns3:equals> ... </ns3:equals> </ns3:requestParameters> </ns2:request> </ns2:getData> </soap:Body> </soap:Envelope> Is there an easy way in C# to send SOAP messages the same way Java client sends: with namespace prefixes? Following is C# code that sends message: // class MyService is auto-generated using wsdl.exe tool MyService service = new MyService(); RequestMessage request = new RequestMessage(); ... ResponseMessage response = service.getData(request); ... UPDATE: RequestMessage class looks like this: /// <remarks/> [System.CodeDom.Compiler.GeneratedCodeAttribute("svcutil", "3.0.4506.2152")] [System.SerializableAttribute()] [System.Diagnostics.DebuggerStepThroughAttribute()] [System.ComponentModel.DesignerCategoryAttribute("code")] [System.Xml.Serialization.XmlTypeAttribute(Namespace="http://uri.etsi.org/02657/v1.5.1#/RetainedData")] public partial class RequestMessage { private byte[] requestPriorityField; private RequestConstraints requestParametersField; private string deliveryPointHIBField; private string maxHitsField; private NationalRequestParameters nationalRequestParametersField; private System.Xml.XmlElement anyField; /// <remarks/> [System.Xml.Serialization.XmlElementAttribute(DataType="hexBinary", Order=0)] public byte[] requestPriority { get { return this.requestPriorityField; } set { this.requestPriorityField = value; } } /// <remarks/> [System.Xml.Serialization.XmlElementAttribute(Order=1)] public RequestConstraints requestParameters { get { return this.requestParametersField; } set { this.requestParametersField = value; } } /// <remarks/> [System.Xml.Serialization.XmlElementAttribute(Order=2)] public string deliveryPointHIB { get { return this.deliveryPointHIBField; } set { this.deliveryPointHIBField = value; } } /// <remarks/> [System.Xml.Serialization.XmlElementAttribute(DataType="integer", Order=3)] public string maxHits { get { return this.maxHitsField; } set { this.maxHitsField = value; } } /// <remarks/> [System.Xml.Serialization.XmlElementAttribute(Order=4)] public NationalRequestParameters nationalRequestParameters { get { return this.nationalRequestParametersField; } set { this.nationalRequestParametersField = value; } } /// <remarks/> [System.Xml.Serialization.XmlAnyElementAttribute(Order=5)] public System.Xml.XmlElement Any { get { return this.anyField; } set { this.anyField = value; } } }

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• many-to-many-to-many, incl alignment of data from diff sources

  - by JefeCoon

  Re-factoring dbase to support many:many:many. At the second and third levels we need to preserve end-user 'mapping' or aligning of data from different sources, e.g. Order 17 FirstpartyOrderID => aha LineItem_for_BigShinyThingy => AA-1 # maps to 77-a LineItem_for_BigShinyThingy => AA-2 # maps to 77-b, 77-c LineItem_for_LittleWidget => AA-x # maps to 77-zulu, 77-alpha, 99-foxtrot LineItem_for_LittleWidget => AA-y # maps to 77-zulu, 99-foxtrot LineItem_for_LittleWidget => AA-z # maps to 77-alpha ThirdpartyOrderID => foo LineItem_for_BigShinyThingy => 77-a LineItem_for_BigShinyThingy => 77-b LineItem_for_BigShinyThingy => 77-c LineItem_for_LittleWidget => 77-zulu LineItem_for_LittleWidget => 77-alpha ThirdpartyOrderID => bar LineItem_for_LittleWidget => 99-foxtrot Each LineItem has daily datapoints reported from its own source (Firstparty|Thirdparty). In our UI & app we provide tools to align these, then we'd like to save them into the cleanest possible schema for querying, enabling us to diff the reported daily datapoints, and perform other daily calculations (which we'll store in the dbase also, fortunately that should be cake once we've nailed this). We need to map related [firstparty|thirdparty]line_items which have their own respective datapoints. We'll be using the association to pull each line_items collection of datapoints for summary and discrepancy calculations. I'm considering two options, std has_many,through x2 --or-- possibly (scary) ubermasterjoin table OptionA: order<<-->> order_join_table[id,order_id,firstparty_order_id,thirdparty_order_id] <<-->>line_item order_join_table[firstparty_order_id]-->raw_order[id] order_join_table[thirdparty_order_id]-->raw_order[id] raw_order-->raw_line_items[raw_order_id] line_item<<-->> line_item_join[id,LI_join_id,firstparty_LI,thirdparty_LI <<-->>raw_line_items line_item_join[firstparty_LI]-->raw_line_item[id] line_item_join[thirdparty_LI]-->raw_line_item[id] raw_line_item<<-->>datapoints = we rely upon join to store all mappings of first|third orders & line_items = keys to raw_* enable lookup of these order & line_item details = concerns about circular references and/or lack of correct mapping logic, e.g order--line_item--raw_line_items vs. order--raw_order--raw_line_items OptionB: order<<-->> join_master[id,order_id,FP_order_id,TP_order_id,FP_line_item_id,TP_line_item_id] join_master[FP_order_id & TP_order_id]-->raw_order[id] join_master[FP_line_item_id & TP_line_item_id]-->raw_line_item[id] = every combo of FP_line_item + TP_line_item writes a record into the join_master table = "theoretically" queries easy/fast/flexible/sexy At long last, my questions: a) any learnings from painful firsthand experience about how best to implement/tune/optimize many-to-many-to-many relationships b) in rails? c) any painful gotchas (circular references, slow queries, spaghetti-monsters) to watch out for? d) any joy & goodness in Rails3 that makes this magically easy & joyful? e) anyone written the "how to do many-to-many-to-many schema in Rails and make it fast & sexy?" tutorial that I somehow haven't found? If not, I'll follow up with our learnings in the hope it's helpful.. Thanks in advance- --Jeff

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• Mutation Problem - Clojure

  - by Silanglaya Valerio

  having trouble changing an element of my function represented as a list. code for random function: (defn makerandomtree-10 [pc maxdepth maxwidth fpx ppx] (if-let [output (if (and (< (rand) fpx) (> maxdepth 0)) (let [head (nth operations (rand-int (count operations))) children (doall (loop[function (list) width maxwidth] (if (pos? width) (recur (concat function (list (makerandomtree-10 pc (dec maxdepth) (+ 2 (rand-int (- maxwidth 1))) fpx ppx))) (dec width)) function)))] (concat (list head) children)) (if (and (< (rand) ppx) (>= pc 0)) (nth parameters (rand-int (count parameters))) (rand-int 100)))] output )) I will provide also a mutation function, which is still not good enough. I need to be able to eval my statement, so the following is still insufficient. (defn mutate-5 "chooses a node changes that" [function pc maxwidth pchange] (if (< (rand) pchange) (let [output (makerandomtree-10 pc 3 maxwidth 0.5 0.6)] (if (seq? output) output (list output))) ;mutate the children of root ;declare an empty accumulator list, with root as its head (let [head (list (first function)) children (loop [acc(list) walker (next function)] (println "----------") (println walker) (println "-----ACC-----") (println acc) (if (not walker) acc (if (or (seq? (first function)) (contains? (set operations) (first function))) (recur (concat acc (mutate-5 walker pc maxwidth pchange)) (next walker)) (if (< (rand) pchange) (if (some (set parameters) walker) (recur (concat acc (list (nth parameters (rand-int (count parameters))))) (if (seq? walker) (next walker) nil)) (recur (concat acc (list (rand-int 100))) (if (seq? walker) (next walker) nil))) (recur acc (if (seq? walker) (next walker) nil)))) ))] (concat head (list children))))) (side note: do you have any links/books for learning clojure?)

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