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  • SQL Saturday #227 - Charleston

    SQL Saturday is coming to Charleston, SC on October 12, 2013. SQL Saturday is a free training event for SQL Server professionals and those wanting to learn about SQL Server. Don't miss Charleston's first SQL Saturday. Understand Locking, Blocking & Row VersioningRead Kalen Delaney's eBook to understand SQL Server concurrency, and use SQL Monitor to pinpoint excessive blocking and deadlocking. Download free resources.

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  • SQL Saturday #238 - Minnesota

    SQL Saturday Minnesota will be on October 12, 2013. This free training event for SQL Server Professionals and those wanting to learn about SQL Server will feature 40 sessions in 8 tracks and 350+ attendees. Understand Locking, Blocking & Row VersioningRead Kalen Delaney's eBook to understand SQL Server concurrency, and use SQL Monitor to pinpoint excessive blocking and deadlocking. Download free resources.

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  • Comparing Nginx+PHP-FPM to Apache-mod_php

    - by Rushi
    I'm running Drupal and trying to figure out the best stack to serve it. Apache + mod_php or Nginx + PHP-FPM I used ApacheBench (ab) and Siege to test both setups and I'm seeing Apache performing better. This surprises me a little bit since I've heard a lot of good things about Nginx + PHP-FPM. My current Nginx setup is something that is a bit out of the box, and the same goes for PHP-FPM What optimizations I can make to speed up the Nginx + PHP-FPM combo over Apache and mo_php ? In my tests using ab, Apache is outperforming Nginx significantly (higher requets/second and finishing tests much faster) I've googled around a bit, but since I've never using Nginx, PHP-FPM or FastCGI, I don't exactly know where to start PHP v5.2.13, Drupal v6, latest PHP-FPM and Nginx compiled from source. Apache v2.0.63 ApacheBench Nginx + PHP-FPM Server Software: nginx/0.7.67 Server Hostname: test2.com Server Port: 80 Concurrency Level: 25 ---> Time taken for tests: 158.510008 seconds Complete requests: 1000 Failed requests: 0 Write errors: 0 ---> Requests per second: 6.31 [#/sec] (mean) Time per request: 3962.750 [ms] (mean) Time per request: 158.510 [ms] (mean, across all concurrent requests) Transfer rate: 181.38 [Kbytes/sec] received ApacheBench Apache using mod_php Server Software: Apache/2.0.63 Server Hostname: test1.com Server Port: 80 Concurrency Level: 25 --> Time taken for tests: 63.556663 seconds Complete requests: 1000 Failed requests: 0 Write errors: 0 --> Requests per second: 15.73 [#/sec] (mean) Time per request: 1588.917 [ms] (mean) Time per request: 63.557 [ms] (mean, across all concurrent requests) Transfer rate: 103.94 [Kbytes/sec] received

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  • Difference in performance: local machine VS amazon medium instance

    - by user644745
    I see a drastic difference in performance matrix when i run it with apache benchmark (ab) in my local machine VS production hosted in amazon medium instance. Same concurrent requests (5) and same total number of requests (111) has been run against both. Amazon has better memory than my local machine. But there are 2 CPUs in my local machine vs 1 CPU in m1.medium. My internet speed is very low at the moment, I am getting Transfer rate as 25.29KBps. How can I improve the performance ? Do not know how to interpret Connect, Processing, Waiting and total in ab output. Here is Localhost: Server Hostname: localhost Server Port: 9999 Document Path: / Document Length: 7631 bytes Concurrency Level: 5 Time taken for tests: 1.424 seconds Complete requests: 111 Failed requests: 102 (Connect: 0, Receive: 0, Length: 102, Exceptions: 0) Write errors: 0 Total transferred: 860808 bytes HTML transferred: 847155 bytes Requests per second: 77.95 [#/sec] (mean) Time per request: 64.148 [ms] (mean) Time per request: 12.830 [ms] (mean, across all concurrent requests) Transfer rate: 590.30 [Kbytes/sec] received Connection Times (ms) min mean[+/-sd] median max Connect: 0 0 0.5 0 1 Processing: 14 63 99.9 43 562 Waiting: 14 60 96.7 39 560 Total: 14 63 99.9 43 563 And this is production: Document Path: / Document Length: 7783 bytes Concurrency Level: 5 Time taken for tests: 33.883 seconds Complete requests: 111 Failed requests: 0 Write errors: 0 Total transferred: 877566 bytes HTML transferred: 863913 bytes Requests per second: 3.28 [#/sec] (mean) Time per request: 1526.258 [ms] (mean) Time per request: 305.252 [ms] (mean, across all concurrent requests) Transfer rate: 25.29 [Kbytes/sec] received Connection Times (ms) min mean[+/-sd] median max Connect: 290 297 14.0 293 413 Processing: 897 1178 63.4 1176 1391 Waiting: 296 606 135.6 588 1171 Total: 1191 1475 66.0 1471 1684

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  • Nginx Slower than Apache??

    - by ichilton
    Hi, I've just setup 2x identical Rackspace Cloud instances and am doing some comparisons and benchmarks to compare Apache and Nginx. I'm testing with a 3.4k png file and initially 512MB server instances but have now moved to 1024MB server instances. I'm very surprised to see that whatever I try, Apache seems to consistently outperform Nginx....what am I doing wrong? Nginx: Server Software: nginx/0.8.54 Server Port: 80 Document Length: 3400 bytes Concurrency Level: 100 Time taken for tests: 2.320 seconds Complete requests: 1000 Failed requests: 0 Write errors: 0 Total transferred: 3612000 bytes HTML transferred: 3400000 bytes Requests per second: 431.01 [#/sec] (mean) Time per request: 232.014 [ms] (mean) Time per request: 2.320 [ms] (mean, across all concurrent requests) Transfer rate: 1520.31 [Kbytes/sec] received Connection Times (ms) min mean[+/-sd] median max Connect: 0 11 15.7 3 120 Processing: 1 35 76.9 20 1674 Waiting: 1 31 73.0 19 1674 Total: 1 46 79.1 21 1693 Percentage of the requests served within a certain time (ms) 50% 21 66% 39 75% 40 80% 40 90% 98 95% 136 98% 269 99% 334 100% 1693 (longest request) And Apache: Server Software: Apache/2.2.16 Server Port: 80 Document Length: 3400 bytes Concurrency Level: 100 Time taken for tests: 1.346 seconds Complete requests: 1000 Failed requests: 0 Write errors: 0 Total transferred: 3647000 bytes HTML transferred: 3400000 bytes Requests per second: 742.90 [#/sec] (mean) Time per request: 134.608 [ms] (mean) Time per request: 1.346 [ms] (mean, across all concurrent requests) Transfer rate: 2645.85 [Kbytes/sec] received Connection Times (ms) min mean[+/-sd] median max Connect: 0 1 3.7 0 27 Processing: 0 3 6.2 1 29 Waiting: 0 2 5.0 1 29 Total: 1 4 7.0 1 29 Percentage of the requests served within a certain time (ms) 50% 1 66% 1 75% 1 80% 1 90% 17 95% 19 98% 26 99% 27 100% 29 (longest request) I'm currently using worker_processes 4; and worker_connections 1024; but i've tried and benchmarked different values and see the same behaviour on all - I just can't get it to perform as well as Apache and from what i've read previously, i'm shocked about this! Can anyone give any advice? Thanks, Ian

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  • How to test server throughput

    - by embwbam
    I've always used apache benchmark to try to get a rough idea of how many requests/second my server can handle. I read that it was good, and it seemed to work well. Enter node.js, which is fully event-based, so it never blocks. If I run apache benchmark on a simple hello world server it can handle 2500 requests per second or so. However, if I put a timeout in the hello world function, so that it responds after 2 seconds, apache benchmark reports a dramatically reduced throughput: about 50/s. I'm running 100 concurrent connections with ab. If I increase the concurrency, it goes up. This makes sense, because apache benchmark is basically sending out requests in batches of 100, which come back every 2 seconds. 100 requests / 2 seconds = 50 requests / second If I increase the concurrency to about 400 or 500, it starts to crash. I don't think I've hit node.js's limit, I think I'm hitting a wall in my operating system on the number of open file descriptors or sockets or something. Any way I can get a good guess about how many requests my server can handle? I want to make sure the test computer isn't the one causing the problem.

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  • AWS elastic load balancer basic issues

    - by Jones
    I have an array of EC2 t1.micro instances behind a load balancer and each node can manage ~100 concurrent users before it starts to get wonky. i would THINK if i have 2 such instances it would allow my network to manage 200 concurrent users... apparently not. When i really slam the server (blitz.io) with a full 275 concurrents, it behaves the same as if there is just one node. it goes from 400ms response time to 1.6 seconds (which for a single t1.micro is expected, but not 6). So the question is, am i simply not doing something right or is ELB effectively worthless? Anyone have some wisdom on this? AB logs: Loadbalancer (3x m1.medium) Document Path: /ping/index.html Document Length: 185 bytes Concurrency Level: 100 Time taken for tests: 11.668 seconds Complete requests: 50000 Failed requests: 0 Write errors: 0 Non-2xx responses: 50001 Total transferred: 19850397 bytes HTML transferred: 9250185 bytes Requests per second: 4285.10 [#/sec] (mean) Time per request: 23.337 [ms] (mean) Time per request: 0.233 [ms] (mean, across all concurrent requests) Transfer rate: 1661.35 [Kbytes/sec] received Connection Times (ms) min mean[+/-sd] median max Connect: 1 2 4.3 2 63 Processing: 2 21 15.1 19 302 Waiting: 2 21 15.0 19 261 Total: 3 23 15.7 21 304 Single instance (1x m1.medium direct connection) Document Path: /ping/index.html Document Length: 185 bytes Concurrency Level: 100 Time taken for tests: 9.597 seconds Complete requests: 50000 Failed requests: 0 Write errors: 0 Non-2xx responses: 50001 Total transferred: 19850397 bytes HTML transferred: 9250185 bytes Requests per second: 5210.19 [#/sec] (mean) Time per request: 19.193 [ms] (mean) Time per request: 0.192 [ms] (mean, across all concurrent requests) Transfer rate: 2020.01 [Kbytes/sec] received Connection Times (ms) min mean[+/-sd] median max Connect: 1 9 128.9 3 3010 Processing: 1 10 8.7 9 141 Waiting: 1 9 8.7 8 140 Total: 2 19 129.0 12 3020

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  • Autocad on linux ubuntu 11.10!

    - by gabriel
    I am trying 3 years now installing autocad,3ds max and revit architecture on ubuntu with the help of wine!Every year i am very optimistic cause i see the new wine versions already improved.So, now i am starting again in a clean ubuntu install to install the autocad 2013 with the wine version wine1.4.I am not trying to have an answer only for me but i want all this ubuntu community try for this and finally we can achieve that!The winetricks have already net framework 4 to install which is the reason i have not already ran in the pas autocad.So, i would like to remove completely my windows 7 partition from my pc and go on a linux machine without loosing the powerfull architectural programms.I know all about blender and staff so i just want you to help find a solution on that because i know there is a solution!Maybe i will have to learn all the c++ or python etc staff.But i am sure that a solution can come with the help of all of us!Any suggestion about this problem will be very nice and helpfull. Thanks in advance! Gabriel

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  • App Store: Profitability for Game Developers

    - by Bunkai.Satori
    Recent days, I've been spending significant time in discovering chances of profitability of AppStore for developers. I have found many articles. Some of them are highly optimistic, while other are extremely skeptical. This article is extremely skeptical. It even claims to have backed its conclusions by objective sales numbers. This is another pesimistic article saying that games developed by single individuals get 20 downloads a day. Can I kindly ask to clarify from business viewpoint whether average developers publishing games and software on AppStore can cover their living expenses, even, whether they can become profitable? Is it achievable to generate revenues of 50.000 USD yearly on AppStore for a single developer? I would like to stay as realistic as possible. Despite the question might look subjective, a good business man will be able to esitmate chances for profitability and prosperity within AppStore.

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  • App Store: Profitability for Game Developers

    - by Bunkai.Satori
    Recent days, I've been spending significant time in discovering chances of profitability of AppStore for developers. I have found many articles. Some of them are highly optimistic, while other are extremely skeptical. This article is extremely skeptical. It even claims to have backed its conclusions by objective sales numbers. This is another pesimistic article saying that games developed by single individuals get 20 downloads a day. Can I kindly ask to clarify from business viewpoint whether average developers publishing games and software on AppStore can cover their living expenses, even, whether they can become profitable? Is it achievable to generate revenues of 50.000 USD yearly on AppStore for a single developer? I would like to stay as realistic as possible. Despite the question might look subjective, a good business man will be able to esitmate chances for profitability and prosperity within AppStore.

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  • How do I let customers run arbitrary code as securely as possible?

    - by Tyler
    I'd like to offer a service where customers can write arbitrary java code, send it to me, and I'll run it for them on Amazon EC2. My question is: how can I do this without exposing one customer's data to another customer? Right now I'm thinking that each customer can be sandboxed as their own OS-level user with restricted permissions. Is that good enough? I understand that this is a tricky issue, but it seems to be one that many people, such as the designers of multi-user OS's and Amazon themselves are solving, so I am optimistic that there might be a good approach.

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  • The Recovery: New Challenges for your Supply Chain!

    - by [email protected]
    Nearly half of CFOs are planning to reduce their inventory during the first half of 2010 in part due to supply chain improvements that allow them to hold less product, but also because of reduced demand according to Kate O'Sullivan, Sr Editor at CFO Magazine. Her view is based on this quarter's Duke University Global Business Outlook Survey. Highlights: Employment will be a drag on the economy- full-time employment to increase by 1%. Temp hiring to grow <1%, Outsourcing 4%.  70% of CFOs at SMEs say credit conditions are worse then 12 mos ago - placing strains on inventory growth Asia and China finance execs are more optimistic than their EMEA or US counterparts and expect stronger growth in capital spending with a 16% gain Source: "Slouching Towards Recovery", CFO Magazine, April 2010, pgs 19-20    

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  • What's the best way to manage list item sort order with Drag & Drop UI?

    - by Reddy S R
    I have a list of Students that I should display to user on a web page in tabular format. The items are stored in DB along with SortOrder information. On the web page, user can rearrange the list order by dragging and dropping the items to their desired sort order, similar to this post. Below is a screenshot of my test page. In the above example, each row has sort order info attached to it. When I drop John Doe (Student Id 10) above the Student Id 1 row, the list order should now be: 2, 10, 1, 8, 11. What's the optimistic (less resource hungry) way to store and update Sort Order information? My only idea for now is, for every change in the list's sort order, every object's SortOrder value should be updated, which in my opinion is very resource hungry. Just FYI: I might have at most 25 rows in my table.

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  • Designing a hierarchical structure with lots of reads and writes?

    - by JD01
    I am in the process of working on a video on demand system part of it involves the management of a hierarchical tree structure (think windows explorer) which allows users to upload videos, move folders around, create new folders etc. User action will be allowed depending on which permissions they have. In addition to managing the structure (creating folders and uploading videos), subscribers will be viewing content (read access). The number of reads will be significantly more than the writes. My question (and it is big one) is should I store the data in a database (for the writes) and also have some sort of cache which will be used for the reads? or do I use two databases? or is there a better solution? Also I will have to resolve concurrency issues which I think optimistic locking on the database will resolve. I have a fair bit about CQRS over the last few months but not sure if this is the way to go. Any ideas?

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  • Forms bound to updateable ADO recordsets are not updateable when the source includes a JOIN

    - by Art
    I'm developing an application in Access 2007. It uses an .accdb front end connecting to an SQL Server 2005 backend. I use forms that are bound to ADO recordsets at runtime. For the sake of efficiency, the recordsets usually contain only one record, and are queried out on the server: Public Sub SetUpFormRecordset(cn As ADODB.Connection, rstIn As ADODB.Recordset, rstSource As String) Dim cmd As ADODB.Command Dim I As Long Set cmd = New ADODB.Command cn.Errors.Clear ' Recordsets based on command object Execute method are Read Only! With cmd Set .ActiveConnection = cn .CommandType = adCmdText .CommandText = rstSource End With With rstIn .CursorType = adOpenKeyset .LockType = adLockPessimistic 'Check the locktype after opening; optimistic locking is worthless on a bound End With ' form, and ADO might open optimistically without firing an error! rstIn.Open cmd, , adOpenKeyset, adLockPessimistic 'This should run the query on the server and return an updatable recordset With cn If .Errors.Count <> 0 Then For Each errADO In .Errors Call HandleADOErrors(.Errors(I)) I = I + 1 Next errADO End If End With End Sub rstSource (the string containg the TSQL on which the recordset is based) is assembled by the calling routine, in this case from the Open event of the form being bound: Private Sub Form_Open(Cancel As Integer) Dim rst As ADODB.Recordset Dim strSource As String, DefaultSource as String Dim lngID As Long lngID = Forms!MyParent.CurrentID strSource = "SELECT TOP (100) PERCENT dbo.Customers.CustomerID, dbo.Customers.LegacyID, dbo.Customers.Active, dbo.Customers.TypeID, dbo.Customers.Category, " & _ "dbo.Customers.Source, dbo.Customers.CustomerName, dbo.Customers.CustAddrID, dbo.Customers.Email, dbo.Customers.TaxExempt, dbo.Customers.SalesTaxCode, " & _ "dbo.Customers.SalesTax2Code, dbo.Customers.CreditLimit, dbo.Customers.CreationDate, dbo.Customers.FirstOrder, dbo.Customers.LastOrder, " & _ "dbo.Customers.nOrders, dbo.Customers.Concurrency, dbo.Customers.LegacyLN, dbo.Addresses.AddrType, dbo.Addresses.AddrLine1, dbo.Addresses.AddrLine2, " & _ "dbo.Addresses.City, dbo.Addresses.State, dbo.Addresses.Country, dbo.Addresses.PostalCode, dbo.Addresses.PhoneLandline, dbo.Addresses.Concurrency " & _ "FROM dbo.Customers INNER JOIN " & _ "dbo.Addresses ON dbo.Customers.CustAddrID = dbo.Addresses.AddrID " strSource = strSource & "WHERE dbo.Customers.CustomerID= " & lngID With Me 'Default is Set up for editing one record If Not Nz(.RecordSource, vbNullString) = vbNullString Then If .Dirty Then .Dirty = False 'Save any changes on the form .RecordSource = vbNullString End If If rst Is Nothing Then 'Might not be first time through DefaultSource = .RecordSource Else rst.Close Set rst = Nothing End If End With Set rst = New ADODB.Recordset Call setupformrecordset(dbconn, rst, strSource) 'dbconn is a global variable With Me Set .Recordset = rst End With End Sub The recordset that is returned from setupformrecordset is fully updateable, and its .Supports property shows this. It can be edited and updated in code. The entire form, however, is read only, even though it's .AllowEdits and .AllowAdditions properties are both true. Even the fields from the right hand side (the 'many' side) cannot be edited. Removing the INNER JOIN clause from the TSQL (restricting strSource to one table) makes the form fully editable. I've verified that the TSQL includes priimary key fields from both tables, and each table includes a timestamp field for concurrency. I tried changing the .CursorType and .CursorLocation properties of the recordset to no avail. What am I doing wrong?

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  • Feb 2nd Links: Visual Studio, ASP.NET, ASP.NET MVC, JQuery, Windows Phone

    - by ScottGu
    Here is the latest in my link-listing series.  Also check out my Best of 2010 Summary for links to 100+ other posts I’ve done in the last year. [I am also now using Twitter for quick updates and to share links. Follow me at: twitter.com/scottgu] Community News MVCConf Conference Next Wednesday: Attend the free, online ASP.NET MVC Conference being organized by the community next Wednesday.  Here is a list of some of the talks you can watch live. Visual Studio HTML5 and CSS3 in VS 2010 SP1: Good post from the Visual Studio web tools team that talks about the new support coming in VS 2010 SP1 for HTML5 and CSS3. Database Deployment with the VS 2010 Package/Publish Database Tool: Rachel Appel has a nice post that covers how to enable database deployment using the built-in VS 2010 web deployment support.  Also check out her ASP.NET web deployment post from last month. VsVim Update Released: Jared posts about the latest update of his VsVim extension for Visual Studio 2010.  This free extension enables VIM based key-bindings within VS. ASP.NET How to Add Mobile Pages to your ASP.NET Web Forms / MVC Apps: Great whitepaper by Steve Sanderson that covers how to mobile-enable your ASP.NET and ASP.NET MVC based applications. New Entity Framework Tutorials for ASP.NET Developers: The ASP.NET and EF teams have put together a bunch of nice tutorials on using the Entity Framework data library with ASP.NET Web Forms. Using ASP.NET Dynamic Data with EF Code First (via NuGet): Nice post from David Ebbo that talks about how to use the new EF Code First Library with ASP.NET Dynamic Data. Common Performance Issues with ASP.NET Web Sites: Good post with lots of performance tuning suggestions (mostly deployment settings) for ASP.NET apps. ASP.NET MVC Razor View Converter: Free, automated tool from Terlik that can convert existing .aspx view templates to Razor view templates. ASP.NET MVC 3 Internationalization: Nadeem has a great post that talks about a variety of techniques you can use to enable Globalization and Localization within your ASP.NET MVC 3 applications. ASP.NET MVC 3 Tutorials by David Hayden: Great set of tutorials and posts by David Hayden on some of the new ASP.NET MVC 3 features. EF Fixed Concurrency Mode and MVC: Chris Sells has a nice post that talks about how to handle concurrency with updates done with EF using ASP.NET MVC. ASP.NET and jQuery jQuery Performance Tips and Tricks: A free 30 minute video that covers some great tips and tricks to keep in mind when using jQuery. jQuery 1.5’s AJAX rewrite and ASP.NET services - All is well: Nice post by Dave Ward that talks about using the new jQuery 1.5 to call ASP.NET ASMX Services. Good news according to Dave is that all is well :-) jQuery UI Modal Dialogs for ASP.NET MVC: Nice post by Rob Regan that talks about a few approaches you can use to implement dialogs with jQuery UI and ASP.NET MVC.  Windows Phone 7 Free PDF eBook on Building Windows Phone 7 Applications with Silverlight: Free book that walksthrough how to use Silverlight and Visual Studio to build Windows Phone 7 applications. Hope this helps, Scott

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  • Clean Code: A Handbook of Agile Software Craftsmanship – book review

    - by DigiMortal
       Writing code that is easy read and test is not something that is easy to achieve. Unfortunately there are still way too much programming students who write awful spaghetti after graduating. But there is one really good book that helps you raise your code to new level – your code will be also communication tool for you and your fellow programmers. “Clean Code: A Handbook of Agile Software Craftsmanship” by Robert C. Martin is excellent book that helps you start writing the easily readable code. Of course, you are the one who has to learn and practice but using this book you have very good guide that keeps you going to right direction. You can start writing better code while you read this book and you can do it right in your current projects – you don’t have to create new guestbook or some other simple application to start practicing. Take the project you are working on and start making it better! My special thanks to Robert C. Martin I want to say my special thanks to Robert C. Martin for this book. There are many books that teach you different stuff and usually you have markable learning curve to go before you start getting results. There are many books that show you the direction to go and then leave you alone figuring out how to achieve all that stuff you just read about. Clean Code gives you a lot more – the mental tools to use so you can go your way to clean code being sure you will be soon there. I am reading books as much as I have time for it. Clean Code is top-level book for developers who have to write working code. Before anything else take Clean Code and read it. You will never regret your decision. I promise. Fragment of editorial review “Even bad code can function. But if code isn’t clean, it can bring a development organization to its knees. Every year, countless hours and significant resources are lost because of poorly written code. But it doesn’t have to be that way. What kind of work will you be doing? You’ll be reading code—lots of code. And you will be challenged to think about what’s right about that code, and what’s wrong with it. More importantly, you will be challenged to reassess your professional values and your commitment to your craft. Readers will come away from this book understanding How to tell the difference between good and bad code How to write good code and how to transform bad code into good code How to create good names, good functions, good objects, and good classes How to format code for maximum readability How to implement complete error handling without obscuring code logic How to unit test and practice test-driven development This book is a must for any developer, software engineer, project manager, team lead, or systems analyst with an interest in producing better code.” Table of contents Clean code Meaningful names Functions Comments Formatting Objects and data structures Error handling Boundaries Unit tests Classes Systems Emergence Concurrency Successive refinement JUnit internals Refactoring SerialDate Smells and heuristics A Concurrency II org.jfree.date.SerialDate Cross references of heuristics Epilogue Index

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  • Throttling in OSB

    - by Knut Vatsendvik
    Technorati Tags: soa,integration,osb,throttling,overload protection A common problem with integration is the risk of overloading a particular web service. When the capacity of a web service is reached and it continues to accept connections, it will most likely start to deteriorate. Fortunately there are 2 techniques, with Oracle Service Bus, that you can apply for protecting this from happening. You can either limit the concurrent number of requests for a Business Service (outbound requests) or you can limit the number of threads processing the requests for a Proxy Service (inbound requests). Limiting the Concurrent Number of Requests Limiting the concurrent requests for a Business Service cannot be set at design time so you have to use the built-in Oracle Service Bus Administration Console to do it (/sbconsole). Follow these steps to enable it: In Change Center, click Create to start a new Session Select Project Explorer, and navigate to the Business Service you want to limit Select the Operational Settings tab of the View a Business Service page In this tab, under Throttling, select the Enable check box. By enabling throttling you Specify a value for Maximum Concurrency Specify a positive integer value for Throttling Queue to backlog messages that has exceeded the message concurrency limit Specify the maximum time in milliseconds for Message Expiration a message can spend in Throttling Queue Click Update Click Active in Change Center to active the new settings If you re-publish the service, it will not overwrite the settings. Only if the resource is renamed or moved, it will. Please note that a throttling queue is an in-memory queue. Messages that are placed in this queue are not recoverable when a server fails or when you restart a server. Limiting the Number of Threads A better approach, in my opinion, is to limit the number of threads that can work with request. Follow these steps to do it: Open the WebLogic Server Console (/console) In Change Center, click Create to start a new Session In the left pane expand Environment and select Work Managers In the Global Work Managers page, click New    Click the Work Manager radio button, then click Next Enter a Name for the new Work Manager, and click Next In the Available Targets list, select server instances or clusters on which you will deploy applications that reference the Work Manager Click Finish. The new Work Manager now appears in the Global Work Managers page. Select the new Work Manager Right next to the Maximum Threads Constraint drop-down box, click New   Click the Maximum Threads Constraint radio button, then click Next Enter a Name and a thread Count to be the maximum size to allocate for requests. Click Next  In the Available Targets list, select server instances or clusters on which you will deploy applications that reference the Work Manager Click Finish Click Save Click Active in Change Center to active your changes.  A restart may be necessary.   Puh! Almost there. Start a new session. Go to the Service Bus Console (/sbconsole) and find your consuming Proxy Service. Click the Edit button of the Transport Configuration tab. Click Next Set the Dispatch Policy to the new Work Manager Click Last Click Save Click Active in Change Center to active your changes. 

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  • Come see us at JavaU at JavaOne!

    - by tmcginn
    In just a little under a month, JavaOne will be in full swing (no pun intended) and thousands of Java developers will gather to hear the latest Java news, immerse themselves in Java technology and learn some new things. This year, I am fortunate enough to be able to attend, along with my Java curriculum development colleagues Matt Heimer and Mike Williams. We start our week at JavaOne teaching a one-day session at JavaU on Sunday morning. If you have never attended a training session through JavaU, you should check it out. There are some terrific sessions this year, and it might help to justify your trip to JavaOne if you can say it was for training! This year I am teaching a one day session on Java SE 7 New Features - a great session for anyone interested in the specific details of what is new in Java SE 7. Matt is teaching a one-day session on Developing Portable Java EE applications with the Enterprise JavaBeans 3.1 API and Java Persistence 2.0 API  EJB, and Mike is doing a one-day session on developing Rich Client applications with Java SE 7 using Java FX 2. I asked Matt and Mike to tell me what developers can expect from their sessions. Matt: "My session will get you up to speed on everything you need to know to create portable Java EE 6 applications using EJB 3.1 and JPA 2. I am going to cover why everyone can benefit from using EJBs (and why developers should relearn them if they haven't looked at them for years). Students who attend my session will see JPA examples showcasing how to use relational databases in an enterprise applications without programming to JDBC and without writing SQL statements. EJB and JPA benefit from being paired together, so I will also show how transaction management is easier in a container. I encourage students to bring a laptop and code as they learn!" Mike: "My session covers how to develop a rich client application using Java FX 2. Starting with the basic concepts of JavaFX, students will see how a JavaFX application is built from its layout, to its controls, to its data structures. In addition, more advanced controls like charts, smart tables, and transitions will be added to the application. Finally, a quick review of JavaFX concurrency and data binding is included. Blended with the core concepts the session will include some of the latest JavaFX technology. This includes using Scene Builder to create a JavaFX UI and connecting your XML UI definition to Java code.  In addition, packaging of the JavaFX application will be covered with some examples of the new native packaging features." As I mentioned, my session covers the changes in the Java for SE 7, including the  language changes that were voted into Java SE 7 from Project Coin. I will also look at how you can take advantage if the the new I/O library (NIO.2) for writing applications that work with files, directories and file systems. We will also look at the changes in Asynchronous I/O that are a part of the changes in NIO/2. We will spend some time looking at the changes to the Java Virtual Machine as well, including support for dynamically typed languages (JSR-292). We will spend some time looking at the Java Concurrency enhancements (JSR-166), including the new Fork/Join framework. And we'll round out the day with a look at changes in Swing, XML and a number of smaller changes in the API's. And, if these topics aren't grabbing your interest, take a look at the other 10 sessions that range from topics on architecture to how to pass the Oracle Certified Programmer I and II exams. See you soon!

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  • Learn Many Languages

    - by Jeff Foster
    My previous blog, Deliberate Practice, discussed the need for developers to “sharpen their pencil” continually, by setting aside time to learn how to tackle problems in different ways. However, the Sapir-Whorf hypothesis, a contested and somewhat-controversial concept from language theory, seems to hold reasonably true when applied to programming languages. It states that: “The structure of a language affects the ways in which its speakers conceptualize their world.” If you’re constrained by a single programming language, the one that dominates your day job, then you only have the tools of that language at your disposal to think about and solve a problem. For example, if you’ve only ever worked with Java, you would never think of passing a function to a method. A good developer needs to learn many languages. You may never deploy them in production, you may never ship code with them, but by learning a new language, you’ll have new ideas that will transfer to your current “day-job” language. With the abundant choices in programming languages, how does one choose which to learn? Alan Perlis sums it up best. “A language that doesn‘t affect the way you think about programming is not worth knowing“ With that in mind, here’s a selection of languages that I think are worth learning and that have certainly changed the way I think about tackling programming problems. Clojure Clojure is a Lisp-based language running on the Java Virtual Machine. The unique property of Lisp is homoiconicity, which means that a Lisp program is a Lisp data structure, and vice-versa. Since we can treat Lisp programs as Lisp data structures, we can write our code generation in the same style as our code. This gives Lisp a uniquely powerful macro system, and makes it ideal for implementing domain specific languages. Clojure also makes software transactional memory a first-class citizen, giving us a new approach to concurrency and dealing with the problems of shared state. Haskell Haskell is a strongly typed, functional programming language. Haskell’s type system is far richer than C# or Java, and allows us to push more of our application logic to compile-time safety. If it compiles, it usually works! Haskell is also a lazy language – we can work with infinite data structures. For example, in a board game we can generate the complete game tree, even if there are billions of possibilities, because the values are computed only as they are needed. Erlang Erlang is a functional language with a strong emphasis on reliability. Erlang’s approach to concurrency uses message passing instead of shared variables, with strong support from both the language itself and the virtual machine. Processes are extremely lightweight, and garbage collection doesn’t require all processes to be paused at the same time, making it feasible for a single program to use millions of processes at once, all without the mental overhead of managing shared state. The Benefits of Multilingualism By studying new languages, even if you won’t ever get the chance to use them in production, you will find yourself open to new ideas and ways of coding in your main language. For example, studying Haskell has taught me that you can do so much more with types and has changed my programming style in C#. A type represents some state a program should have, and a type should not be able to represent an invalid state. I often find myself refactoring methods like this… void SomeMethod(bool doThis, bool doThat) { if (!(doThis ^ doThat)) throw new ArgumentException(“At least one arg should be true”); if (doThis) DoThis(); if (doThat) DoThat(); } …into a type-based solution, like this: enum Action { DoThis, DoThat, Both }; void SomeMethod(Action action) { if (action == Action.DoThis || action == Action.Both) DoThis(); if (action == Action.DoThat || action == Action.Both) DoThat(); } At this point, I’ve removed the runtime exception in favor of a compile-time check. This is a trivial example, but is just one of many ideas that I’ve taken from one language and implemented in another.

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  • nHibernate strategies in a web farm

    - by Pete Nelson
    Our current project at work is a new MVC web site that will use a WCF service primarily to access a 3rd party billing system via a web service as well as a small SQL database for user personalization. The WCF service uses nHibernate for the SQL database. We'd like to implement some sort of web farm for load balancing as well as failover and maintenance. I'm trying to decide the best way to handle nHibernate's caching and database concurrency if there are multiple WCF services running. Some scenarios I've been thinking about... 1) Multiple IIS servers, one WCF server. With this setup, the WCF server would be a single point of failure, but there would be no issues with nHibernate caching or database concurrency. 2) Multiple IIS servers, each with it's own WCF service. This removes a single point of failure, but now nHibernate on one machine would not know about database changes done by another machine. Some solutions to number 2 would be to use an IStatelessSession so we're not doing any caching and nHibernate is always fetching directly from the database. This might be the most feasible as our personalization database has very few objects in it. I'm also considering a 2nd-level cache such as memcached or Velocity, but it may be overkill for this system. I'm putting this out there to see if anyone has experience doing this sort of architecture and to get some ideas for a solution. Thanks!

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  • Python Socket Getting Connection Reset

    - by Ian
    I created a threaded socket listener that stores newly accepted connections in a queue. The socket threads then read from the queue and respond. For some reason, when doing benchmarking with 'ab' (apache benchmark) using a concurrency of 2 or more, I always get a connection reset before it's able to complete the benchmark (this is taking place locally, so there's no external connection issue). class server: _ip = '' _port = 8888 def __init__(self, ip=None, port=None): if ip is not None: self._ip = ip if port is not None: self._port = port self.server_listener(self._ip, self._port) def now(self): return time.ctime(time.time()) def http_responder(self, conn, addr): httpobj = http_builder() httpobj.header('HTTP/1.1 200 OK') httpobj.header('Content-Type: text/html; charset=UTF-8') httpobj.header('Connection: close') httpobj.body("Everything looks good") data = httpobj.generate() sent = conn.sendall(data) def http_thread(self, id): self.log("THREAD %d: Starting Up..." % id) while True: conn, addr = self.q.get() ip, port = addr self.log("THREAD %d: responding to request: %s:%s - %s" % (id, ip, port, self.now())) self.http_responder(conn, addr) self.q.task_done() conn.close() def server_listener(self, host, port): self.q = Queue.Queue(0) sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM) sock.bind( (host, port) ) sock.listen(5) for i in xrange(4): #thread count thread.start_new(self.http_thread, (i+1, )) while True: self.q.put(sock.accept()) sock.close() server('', 9999) When running the benchmark, I get totally random numbers of good requests before it errors out, usually between 4 and 500. Edit: Took me a while to figure it out, but the problem was in sock.listen(5). Because I was using apache benchmark with a higher concurrency (5 and up) it was causing the backlog of connections to pile up, at which point the connections started getting dropped by the socket.

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  • Hibernate mapping to object that already exists

    - by teehoo
    I have two classes, ServiceType and ServiceRequest. Every ServiceRequest must specify what kind of ServiceType it is. All ServiceType's are predefined in the database, and ServiceRequest is created at runtime by the client. Here are my .hbm files: <hibernate-mapping> <class dynamic-insert="false" dynamic-update="false" mutable="true" name="xxx.model.entity.ServiceRequest" optimistic-lock="version" polymorphism="implicit" select-before-update="false"> <id column="USER_ID" name="id"> <generator class="native"/> </id> <property name="quantity"> <column name="quantity" not-null="true"/> </property> <many-to-one cascade="all" class="xxx.model.entity.ServiceType" column="service_type" name="serviceType" not-null="false" unique="false"/> </class> </hibernate-mapping> and <hibernate-mapping> <class dynamic-insert="false" dynamic-update="false" mutable="true" name="xxx.model.entity.ServiceType" optimistic-lock="version" polymorphism="implicit" select-before-update="false"> <id column="USER_ID" name="id"> <generator class="native"/> </id> <property name="description"> <column name="description" not-null="false"/> </property> <property name="cost"> <column name="cost" not-null="true"/> </property> <property name="enabled"> <column name="enabled" not-null="true"/> </property> </class> </hibernate-mapping> When I run this, I get com.mysql.jdbc.exceptions.MySQLIntegrityConstraintViolationException: Cannot add or update a child row: a foreign key constraint fails I think my problem is that when I create a new ServiceRequest object, ServiceType is one of its properties, and therefore when I'm saving ServiceRequest to the database, Hibernate attempts to insert the ServiceType object once again, and finds that it is already exists. If this is the case, how do I make it so that Hibernate points to the exists ServiceType instead of trying to insert it again?

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  • Simple continuously running XMPP client in python

    - by tom
    I'm using python-xmpp to send jabber messages. Everything works fine except that every time I want to send messages (every 15 minutes) I need to reconnect to the jabber server, and in the meantime the sending client is offline and cannot receive messages. So I want to write a really simple, indefinitely running xmpp client, that is online the whole time and can send (and receive) messages when required. My trivial (non-working) approach: import time import xmpp class Jabber(object): def __init__(self): server = 'example.com' username = 'bot' passwd = 'password' self.client = xmpp.Client(server) self.client.connect(server=(server, 5222)) self.client.auth(username, passwd, 'bot') self.client.sendInitPresence() self.sleep() def sleep(self): self.awake = False delay = 1 while not self.awake: time.sleep(delay) def wake(self): self.awake = True def auth(self, jid): self.client.getRoster().Authorize(jid) self.sleep() def send(self, jid, msg): message = xmpp.Message(jid, msg) message.setAttr('type', 'chat') self.client.send(message) self.sleep() if __name__ == '__main__': j = Jabber() time.sleep(3) j.wake() j.send('[email protected]', 'hello world') time.sleep(30) The problem here seems to be that I cannot wake it up. My best guess is that I need some kind of concurrency. Is that true, and if so how would I best go about that? EDIT: After looking into all the options concerning concurrency, I decided to go with twisted and wokkel. If I could, I would delete this post.

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