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• ASP.NET High CPU Bringing Servers to their Knees

  - by user880954

  Ok, our new build is having 100% cpu spikes on each server at random intervals. For long durations it make the site totally unresponsive - this will be at peak times as people in different countries log on to the site etc. We've looked at perfmom, memory profilers, CLR profiler, sql profilers, Red gate ants profiler, tried load testing in UAT - but cannot even reproduce the problem. This could mean only thousands of users hitting the live site causes it to happen. One pattern we did notice was that the new code - the broken build - actually uses noticably less threads. We are also using spring for IOC - does this have a bed reputation? To make things worse, we cannot deploy to live due to the business impact - so cannot narrow the problem down to subset of the new features we've added. We truly are destroyed - has anyone got any battle scars that may save us a few lives?

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• How do you decide what kind of database to use?

  - by Jason Baker

  I really dislike the name "NoSQL", because it isn't very descriptive. It tells me what the databases aren't where I'm more interested in what the databases are. I really think that this category really encompasses several categories of database. I'm just trying to get a general idea of what job each particular database is the best tool for. A few assumptions I'd like to make (and would ask you to make): Assume that you have the capability to hire any number of brilliant engineers who are equally experienced with every database technology that has ever existed. Assume you have the technical infrastructure to support any given database (including available servers and sysadmins who can support said database). Assume that each database has the best support possible for free. Assume you have 100% buy-in from management. Assume you have an infinite amount of money to throw at the problem. Now, I realize that the above assumptions eliminate a lot of valid considerations that are involved in choosing a database, but my focus is on figuring out what database is best for the job on a purely technical level. So, given the above assumptions, the question is: what jobs are each database (including both SQL and NoSQL) the best tool for and why?

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• Saving Dragged Dropped items position on postback in asp.net [closed]

  - by Deeptechtons

  Ok i saw many post's on how to serialize the value of dragged items to get hash and they tell how to save them. Now the question is how do i persist the dragged items the next time when user log's in using the has value that i got eg: <ul class="list"> <li id="id_1"> <div class="item ui-corner-all ui-widget ui-widget-content"> </div> </li> <li id="id_2"> <div class="item ui-corner-all ui-widget ui-widget-content"> </div> </li> <li id="id_3"> <div class="item ui-corner-all ui-widget ui-widget-content"> </div> </li> <li id="id_4"> <div class="item ui-corner-all ui-widget"> </div> </li> </ul> which on serialize will give "id[]=1&id[]=2&id[]=3&id[]=4" Now think that i saved it to Sql server database in a single field called SortOrder. Now how do i get the items to these order again ? the code to make these sort is below,without which people didn't know which library i had used to sort and serialize <script type="text/javascript"> $(document).ready(function() { $(".list li").css("cursor", "move"); $(".list").sortable(); }); </script>

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• What is the best approach for database design with lots of columns?

  - by Pratyush

  I am writing a query based financial application. It lets the user to write complicated equations (much like WHERE part of an SQL query) and find companies matching those criteria. For the above, I currently have more than 500 columns in the database table (each column representing a financial field). Example of Columns are: company_name, sales_annual_00, sales_annual_01, sales_annual_02, sales_annual_03, sales_annual_04, protit_annual_00, profit_annual1...(over 500 such columns). The number of rows is around 5000. Going forward, I would like to further increase the number of columns/financial-fields. For the above I would like to get help regarding: 1) What is the best database design approach? Is it ok to have these many number of columns? 2) How can it be normalized? (User can use any of these fields in search criteria). 3) Is it ok to stick with MySQL, or modern document based databases like MongoDB should be better for it? P.S. (Update): I have been using MySQL till now and a running example of the usage is at: http://screener.in/companies/89/Formula-- In above there around 500 fields/columns to create your query on, however, I seek to increase that number to much more in future.

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• Database Driven Web Application, C# Front-End and F# Back-End meaning

  - by user1473053

  Hi I am an intern working with ASP.NET. My current task is to make a website which will incorporate some jquery viewing features. This project seems to me will be primarily dealing with reading data from a database and making graphs out of them. This will require me to make custom queries from whatever the client is looking at. I think it is going to be what this guy calls an Ad Hoc Query tool My plan for this is to make it a database-driven website. So I can utilize the jquery dynamic viewing capabilities. I stumbled upon the functional programming paradigm and found F#. I read that because of it's functional programming paradigm, it makes it a good language to do asynchronous functions. I read about how you can use this with LINQ to SQL and how easy it is to make queries without actually putting the query language in. I understand the concept of the MVC design pattern. But I don't understand what they mean about C# being the front-end and F# being the back-end. Can someone clarify this to me? Also what are your thoughts about doing this project in this way? Any comments and thoughts are greatly appreciated. I feel as if learning F# will be a great learning experience for me. My guess is that the F# back-end is like the part where it controls the calls to the database. F# is possibly the model part of the design pattern. And C# is the controller. So HTML, Javascript and Jquery stuff will be my View design pattern. Clarify please?

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• Is this a ridiculous way to structure a DB schema, or am I completely missing something?

  - by Jim

  I have done a fair bit of work with relational databases, and think I understand the basic concepts of good schema design pretty well. I recently was tasked with taking over a project where the DB was designed by a highly-paid consultant. Please let me know if my gut intinct - "WTF??!?" - is warranted, or is this guy such a genius that he's operating out of my realm? DB in question is an in-house app used to enter requests from employees. Just looking at a small section of it, you have information on the users, and information on the request being made. I would design this like so: User table: UserID (primary Key, indexed, no dupes) FirstName LastName Department Request table RequestID (primary Key, indexed, no dupes) <...> various data fields containing request details UserID -- foreign key associated with User table Simple, right? Consultant designed it like this (with sample data): UsersTable UserID FirstName LastName 234 John Doe 516 Jane Doe 123 Foo Bar DepartmentsTable DepartmentID Name 1 Sales 2 HR 3 IT UserDepartmentTable UserDepartmentID UserID Department 1 234 2 2 516 2 3 123 1 RequestTable RequestID UserID <...> 1 516 blah 2 516 blah 3 234 blah The entire database is constructed like this, with every piece of data encapsulated in its own table, with numeric IDs linking everything together. Apparently the consultant had read about OLAP and wanted the 'speed of integer lookups' He also has a large number of stored procedures to cross reference all of these tables. Is this valid design for a small to mid-sized SQL DB? Thanks for comments/answers...

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• How does MySQL 5.5 and InnoDB on Linux use RAM?

  - by Loren

  Does MySQL 5.5 InnoDB keep indexes in memory and tables on disk? Does it ever do it's own in-memory caching of part or whole tables? Or does it completely rely on the OS page cache (I'm guessing that it does since Facebook's SSD cache that was built for MySQL was done at the OS-level: https://github.com/facebook/flashcache/)? Does Linux by default use all of the available RAM for the page cache? So if RAM size exceeds table size + memory used by processes, then when MySQL server starts and reads the whole table for the first time it will be from disk, and from that point on the whole table is in RAM? So using Alchemy Database (SQL on top of Redis, everything always in RAM: http://code.google.com/p/alchemydatabase/) shouldn't be much faster than MySQL, given the same size RAM and database?

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• Determine All SQL Server Table Sizes

  Im doing some work to migrate and optimize a large-ish (40GB) SQL Server database at the moment.  Moving such a database between data centers over the Internet is not without its challenges.  In my case, virtually all of the size of the database is the result of one table, which has over 200M rows of data.  To determine the size of this table on disk, you can run the sp_TableSize stored procedure, like so: EXEC sp_spaceused lq_ActivityLog This results in the following: Of course this is only showing one table if you have a lot of tables and need to know which ones are taking up the most space, it would be nice if you could run a query to list all of the tables, perhaps ordered by the space theyre taking up.  Thanks to Mitchel Sellers (and Gregg Starks CURSOR template) and a tiny bit of my own edits, now you can!  Create the stored procedure below and call it to see a listing of all user tables in your database, ordered by their reserved space. -- Lists Space Used for all user tablesCREATE PROCEDURE GetAllTableSizesASDECLARE @TableName VARCHAR(100)DECLARE tableCursor CURSOR FORWARD_ONLYFOR select [name]from dbo.sysobjects where OBJECTPROPERTY(id, N'IsUserTable') = 1FOR READ ONLYCREATE TABLE #TempTable( tableName varchar(100), numberofRows varchar(100), reservedSize varchar(50), dataSize varchar(50), indexSize varchar(50), unusedSize varchar(50))OPEN tableCursorWHILE (1=1)BEGIN FETCH NEXT FROM tableCursor INTO @TableName IF(@@FETCH_STATUS<>0) BREAK; INSERT #TempTable EXEC sp_spaceused @TableNameENDCLOSE tableCursorDEALLOCATE tableCursorUPDATE #TempTableSET reservedSize = REPLACE(reservedSize, ' KB', '')SELECT tableName 'Table Name',numberofRows 'Total Rows',reservedSize 'Reserved KB',dataSize 'Data Size',indexSize 'Index Size',unusedSize 'Unused Size'FROM #TempTableORDER BY CONVERT(bigint,reservedSize) DESCDROP TABLE #TempTableGO 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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• We are moving an Access based corporate front-end into a Web-based App

  - by Max Vernon

  We have an enterprise application with a front end written in Microsoft Access 2003 that has evolved over the past 6 years. The back end data, and a fair amount of back-end logic is contained within several Microsoft SQL Server databases. This front end app consists of around 180 forms, and over 120,000 lines of code, and interacts with VB.Net DLLs that support various critical functions used by our sales force. The current system makes use of 3 monitors to display various information; the Access app uses COM+ to control Microsoft Outlook and Internet Explorer for various purposes. The Access front end sometimes occupies 2 screens, automatically resizing itself based on Windows API-reported screen dimensions. The app also uses a Google map to present data to our agents, and allows two-way interactivity with the map through COM+ connectivity to JavaScript contained in the Google map. At the urging of senior management, we are looking to completely rewrite this application using some web-based technology, such as ASP.Net or perhaps a LAMP stack (the thinking with the LAMP stack thing is "free" is pretty cheap). We want to move to a web-based app so we can eliminate the dependency on our physical location for hiring new sales force members. Currently, our main office is full to capacity, and we need to continue growing the company. Does anyone have any thoughts on what would be the best technology to use for a web-based app of this magnitude? Keeping in mind the app is dependent on back-end services on our existing infrastructure. The app handles financial data and personal customer data, among other things. [I've looked at Best practices for moving large MS Access application towards .Net? and read the answers, and most of the comments. Interesting reading, and has some valid points, but our C.O.O. and contracted Software Architect are pushing for a full web-based app, not a .Net Windows App]

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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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• T-SQL Tuesday #34: Help me, Obi-Wan Kenobi, You're My Only Hope!

  - by AllenMWhite

  This T-SQL Tuesday is about a person that helped you understand SQL Server. It's not a stretch to say that it's people that help you get to where you are in life, and Rob Volk ( @sql_r ) is sponsoring this month's T-SQL Tuesday asking who is that person that helped you get there. Over the years, there've been a number of people who've helped me, but one person stands out above the rest, who was patient, kind and always explained the details in a way that just made sense. I first met Don Vilen at...(read more)

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• Database Mail and SMO are indeed supported on 64-bit, Standard Edition instances of SQL Server 2012

  - by Argenis

    This is something that comes up rather regularly at forums, so I decided to create a quick post to make sure that folks out there can feel better about SQL Server 2012. If you read this Web article, “Features Supported By Editions of SQL Server 2012” as of time of writing this post, you will see that the article points out that these two features are not supported on x64 Standard Edition. This is NOT correct. It is most definitely a documentation bug – one that unfortunately has caused some customers to sit on a waiting pattern before upgrading to SQL Server 2012. Database Mail and SMO indeed work and are fully supported on SQL Server 2012 Standard Edition x64 instances. These features work as they should. I have contacted the documentation teams internally to make sure that this is reflected on next releases of said Web article.

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• Should SQL Server tools target wide screen formats instead of portrait formats?

  - by Greg Low

  There was a short discussion on the SQL Down Under mailing list this morning about screen resolutions for working with the SQL Server tools. In particular, the issue was about how unusable the tools are on the 1366x768 resolution notebooks that now seem to be the most common. While finding a notebook with an appropriate resolution is obviously the answer at this time, I started thinking that the product itself needs to address this. SQL Server tools currently target a portrait 4:3 shape for minimum...(read more)

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• Is realtime validation of username good or bad?

  - by iamserious

  I have a simple form for the user to sign up to my site; with email, username and password fields. We are now trying to implement an ajax validation so the user doesn't have to post the form to find out if the username is already taken. I can do this either on keyup event or on text blur event. My question is, which of these is really the best way to do? Keyup From the user POV, it would be good if the validation is done as and when they are typing, (on key up event) - of course, I am waiting for half a second to see if the user stops typing before firing off the request, and user can make any adjustments immediately. But this means I am sending way more requests than if I validated the username on Blur event. Blur The number of requests will be much lower when the validation is done on blur event, But this means the user has to actually go away from the textbox, look at the validation result, and if necessary go back to it to make any changes and repeat the whole process until he gets it right. I had a quick look at google, tumblr, twitter and no one actually does username validations on keyup events, (heck, tubmlr waits for the form to be posted) but I can swear I have seen keyup validations in a lot of places too. So, coming back to the question, will keyup validations be too many for server, is it an unnecessary overhead? or is it worth taking these hits to give user a better experience? ps: all my regex validations etc are already done on javascript and only when it passes all these other criteria does it send a request to server to check if a username already exists. (And the server is doing a select count(1) from user where username = '' - nothing substantial, but still enough to occupy some resource) pps: I'm on asp.net, MS SQL stack., if that matters.

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• An algorithm for finding subset matching criteria?

  - by Macin

  I recently came up with a problem which I would like to share some thoughts about with someone on this forum. This relates to finding a subset. In reality it is more complicated, but I tried to present it here using some simpler concepts. To make things easier, I created this conceptual DB model: Let's assume this is a DB for storing recipes. Recipe can have many instructions steps and many ingredients. Ingredients are stored in a cupboard and we know how much of each ingredient we have. Now, when we create a recipe, we have to define how much of each ingredient we need. When we want to use a recipe, we would just check if required amount is less than available amount for each product and then decide if we can cook a dinner - if amount required for at least one ingredient is less than available amount - recipe cannot be cooked. Simple sql query to get the result. This is straightforward, but I'm wondering, how should I work when the problem is stated the other way round, i.e. how to find recipies which can be cooked only from ingredients that are available? I hope my explanation is clear, but if you need any more clarification, please ask.

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• Stairway to T-SQL DML Level 8: Using the ROLLUP, CUBE and GROUPING SET operator in a GROUP BY Clause

  In this article I will be expanding on my discussion of the GROUP BY clause by exploring the ROLLUP, CUBE and GROUPING SETS operators. These additional GROUP BY operators make it is easy to have SQL Server create subtotals, grand totals, a superset of subtotals, as well as multiple aggregate groupings in a single SELECT statement. Local evaluation repository makes trying SQL Source Control simpleThe evaluation repository makes it easy to try SQL Source Control. Get started with the 28-day free trial.

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• How to receive alerts when you centralize your SQL Server Event Logs.

  Learn how you can get alerts when you centralize the Event log. This is part 2 of the previous article "How to centralize your SQL Server Event Logs." What are your servers really trying to tell you? Find out with new SQL Monitor 3.0, an easy-to-use tool built for no-nonsense database professionals.For effortless insights into SQL Server, download a free trial today.

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• SQL Server 2008 System Functions to Monitor the Instance, Database, Files, etc.

  SQL Server provides several system meta data functions which allow users to obtain property values of different SQL Server objects and securables. Although you can also use the SQL Server catalog views or Dynamic Management Views to obtain much of this information, in some circumstances the system meta data functions simplify the process. In this tip I am going to demonstrate some of the available system meta data functions and their usage in different scenarios.

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• Windows system monitoring and profiling

  - by Aris

  I have several dozen 64-bit Windows 2003 servers in a high performance environment with very bursty system utilization. I am looking for a tool (or tools) to monitor and analyze system performance (eg, CPU utilization, bandwidth, etc). This tool can either query servers from a central location (SNMP) or require installation of a component on each server. It should poll on a 1-second interval. It should be able to generate pretty graphs which show trends over time. As a nice-to-have, it should be able to send out emails or IMs when certain thresholds are exceeded. The tools I have investigated so far, including Solarwinds and PRTG, are not designed to poll this frequently. They seem to be designed for a ~30-second interval. Solarwinds wouldn't go lower than 3-sec, and PRTG chokes at 1-sec. They both default to 1-min. All three tools seem more focused on outage monitoring and reporting than metric collection. Given the bursty nature of our applications, such infrequent polling would result in a very inaccurate picture of performance. I am considering rolling my own solution using perfmon. This would be a lot of work, and seems like reinventing the wheel. Are there any tools out there that meet my needs?

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• Preloading Winforms

  - by msarchet

  I am currently working on a project where we have a couple very control heavy user controls that are being used inside a MDI Controller. This is a Line of Business app and it is very data driven. The problem that we were facing was the aforementioned controls would load very very slowly, we dipped our toes into the waters of multi-threading for the control loading but that was not a solution for a plethora of reasons. Our solution to increasing the performance of the controls ended up being to 'pre-load' the forms onto a hidden window, create a stack of the existing forms, and pop off of the stack as the user requested a form. Now the current issue that I'm seeing that will arise as we push this 'fix' out to our testers, and the ultimately our users is this: Currently the 'hidden' window that contains the preloaded forms is visible in task manager, and can be shut down thus causing all of the controls to be lost. Then you have to create them on the fly losing the performance increase. Secondly, when the user uses up the stack we lose the performance increase (current solution to this is discussed below). For the first problem, is there a way to hide this window from task manager, perhaps by creating a parent form that encapsulates both the main form for the program and the hidden form? Our current solution to the second problem is to have an inactivity timer that when it fires checks the stacks for the forms, and loads a new form onto the stack if it isn't full. However this still has the potential of causing a hang in the UI while it creates the forms. A possible solutions for this would be to put 'used' forms back onto the stack, but I feel like there may be a better way.

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• How to modernize an enormous legacy database?

  - by smayers81

  I have a question, just looking for suggestions here. So, my application is 'modernizing' a desktop application by converting it to the web, with an ICEFaces UI and server side written in Java. However, they are keeping around the same Oracle database, which at current count has about 700-900 tables and probably a billion total records in the tables. Some individual tables have 250 million rows, many have over 25 million. Needless to say, the database is not scaling well. As a result, the performance of the application is looking to be abysmal. The architects / decision makers-that-be have all either refused or are unwilling to restructure the persistence. So, basically we are putting a fresh coat of paint on a functional desktop application that currently serves most user needs and does so with relative ease and quick performance. I am having trouble sleeping at night thinking of how poorly this application is going to perform and how difficult it is going to be for everyday users to do their job. So, my question is, what options do I have to mitigate this impending disaster? Is there some type of intermediate layer I can put in between the database and the Java code to speed up performance while at the same time keeping the database structure intact? Caching is obviously an option, but I don't see that as being a cure-all. Is it possible to layer a NoSQL DB in between or something?

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• How can I apply a PSSM efficiently?

  - by flies

  I am fitting for position specific scoring matrices (PSSM aka Position Specific Weight Matrices). The fit I'm using is like simulated annealing, where I the perturb the PSSM, compare the prediction to experiment and accept the change if it improves agreement. This means I apply the PSSM millions of times per fit; performance is critical. In my particular problem, I'm applying a PSSM for an object of length L (~8 bp) at every position of a DNA sequence of length M (~30 bp) (so there are M-L+1 valid positions). I need an efficient algorithm to apply a PSSM. Can anyone help improve performance? My best idea is to convert the DNA into some kind of a matrix so that applying the PSSM is matrix multiplication. There are efficient linear algebra libraries out there (e.g. BLAS), but I'm not sure how best to turn an M-length DNA sequence into a matrix M x 4 matrix and then apply the PSSM at each position. The solution needs to work for higher order/dinucleotide terms in the PSSM - presumably this means representing the sequence-matrix for mono-nucleotides and separately for dinucleotides. My current solution iterates over each position m, then over each letter in word from m to m+L-1, adding the corresponding term in the matrix. I'm storing the matrix as a multi-dimensional STL vector, and profiling has revealed that a lot of the computation time is just accessing the elements of the PSSM (with similar performance bottlenecks accessing the DNA sequence). If someone has an idea besides matrix multiplication, I'm all ears.

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• What do you use to play sound in iPhone games?

  - by zoul

  Hello! I have a performance-intensive iPhone game I would like to add sounds to. There seem to be about three main choices: (1) AVAudioPlayer, (2) Audio Queues and (3) OpenAL. I’d hate to write pages of low-level code just to play a sample, so that I would like to use AVAudioPlayer. The problem is that it seems to kill the performace – I’ve done a simple measuring using CFAbsoluteTimeGetCurrent and the play message seems to take somewhere from 9 to 30 ms to finish. That’s quite miserable, considering that 25 ms == 40 fps. Of course there is the prepareToPlay method that should speed things up. That’s why I wrote a simple class that keeps several AVAudioPlayers at its disposal, prepares them beforehand and then plays the sample using the prepared player. No cigar, still it takes the ~20 ms I mentioned above. Such performance is unusable for games, so what do you use to play sounds with a decent performance on iPhone? Am I doing something wrong with the AVAudioPlayer? Do you play sounds with Audio Queues? (I’ve written something akin to AVAudioPlayer before 2.2 came out and I would love to spare that experience.) Do you use OpenAL? If yes, is there a simple way to play sounds with OpenAL, or do you have to write pages of code? Update: Yes, playing sounds with OpenAL is fairly simple.

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• Limiting object allocation over multiple threads

  - by John

  I have an application which retrieves and caches the results of a clients query. The client then requests different chunks of data and the application sends the relevant results and removes them from the cache. A new requirement for this application is that there needs to be a run-time configurable maximum number of results which may be cached. I've taken the naive approach and implemented this by using a counter under a lock which is incremented every time a result is cached and decremented whenever a result is removed from the cache. Unfortunately, this has drastically reduced the applications performance when processing a large number of concurrent requests. I have tried both a critical section lock and spin-lock; the performance improves a bit with a spin-lock, but is still unacceptably slow. Is there a better way to solve this problem which may improve performance? Right now I have a thread pool that services requests and each request is tied to a Request object which stores that cached results for that particular request. Here is a simplified pseudo code version of my current implementation: void ResultCallback( Result result, Request *request ) { lock totalResultsCached lock cachedLimit if( totalResultsCached + 1 > cachedLimit ) { unlock cachedLimit unlock totalResultsCached //cancel the request return; } ++totalResultsCached; unlock cachedLimit unlock totalResultsCached request.add(result) } void SendResults( int resultsToSend, Request *request ) { while ( resultsToSend > 0 ) { send(request.remove()) lock totalResultsCached --totalResultsCached unlock totalResultsCached --resultsToSend; } }

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• Low Throughput on Windows Named Pipe Over WAN

  - by MichaelB76

  I'm having problems with low performance using a Windows named pipe. The throughput drops off rapidly as the network latency increases. There is a roughly linear relationship between messages sent per second and round trip time. It seems that the client must ack each message before the server will send the next one. This leads to very poor performance, I can only send 5 (~100 byte) messages per second over a link with an RTT of 200 ms. The pipe is asynchronous, using multiple overlapped write operations (and multiple overlapped reads at the client end), but this is not improving throughput. Is it possible to send messages in parallel over a named pipe? The pipe is created using PIPE_TYPE_MESSAGE, would PIPE_READMODE_BYTE work better? Is there any other way I can improve performance? This is a deployed solution, so I can't simply replace the pipe with a socket connection (I've read that Windows named pipe aren't recommended for use over a WAN, and I'm wondering if this is why). I'd be grateful for any help with this matter.

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