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  • Why DbContext object shouldn't be referred in Service Layer?

    - by nazmoonnoor
    I've been looking for some implementations of Service Layer and Controller interaction in blogs and in some open source projects. All of them seem to refer DbContext object in repository classes but avoided to use in service classes. Service classes essentially using a IQueryable<T> references of DbSet<T>. I want to know why this practice is good and why DbContext shouldn't have a reference in Service Layer.

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  • I have data that sends in "bursts" of 100 records with a significant delay. How do I structure my classes for multithreading?

    - by makerofthings7
    My datasource sends information in 100 batches of 100 records with a delay of 1 to 3 seconds between batches. I would like to start processing data as soon as it's received, but I'm not sure how to best approach this. Some ideas I've been playing with include: yield Concurrent Dictionary ConcurrentDictionary with INotifyProperyChanged Events etc. As you can see I'm all over the place, and would appreciate some tested guidance on how to approach this

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  • Dependency injection: At what point am I allowed to create a new object?

    - by Gaz_Edge
    I am refactoring a PHP application, and I am trying to do has much dependency injection (DI) as possible. I feel like I've got a good grasp of how it works, and I can certainly see my classes becoming a lot leaner and more robust. I'm refactoring so that I can inject a dependency rather than create a new object within the class, but at some point I am going to have to create some objects, that is, use the dreaded new keyword. The problem I have now run into is at what point can I actually create new objects? It's looking like I'll end up at a top level class, creating loads of new objects as there is no where else to go. This feels wrong. I've read some blogs that use factory classes to create all the objects, and then you inject the factory into other classes. You can then call the factory methods, and the factory creates the new object for you. My concern with doing this is now my factory classes are going to be a new free-for-all! I guess this may be OK as they are factory classes, but are there some rules to stick to when using a factory pattern and DI, or am I going way off the mark here?

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  • A friend told me Python is garbage, I'm taking web design classes in the Spring and I have a textbook on C++. What should I do? [on hold]

    - by user107165
    I dont know if I should start digging into Python beforehand just to get acquanited with programming and "whet my appetite" or if I should work on the C++ book... Python definitely has more resources around town and I like the beginner friendly approach that seems to go along with every site that appeals to it. Or should I just wait for my assignments that start in 4 months? Any tips for an aspiring programmer?

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  • Dependency Injection: What point am I allowed to create a new object?

    - by Gaz_Edge
    I am refactoring a php application and I am trying to do has much dependency injection as possible. I feel like I've got a good grasp of how it works, and I can certainly see my classes becoming a lot leaner and more robust. Im refactoring so that I can inject a dependency rather than create a new object within the class, but at some point I am going to have to create some objects i.e. use the dreaded new keyword. The problem I have now run into is at what point can I actually create new objects? Its looking like I'll end up at a top level class, creating loads of new objects as there is no where else to go. This feels wrong. I've read some blogs that use factory classes to create all the objects, and then you inject the factory into other classes. You can then call the factory methods, and the factory creates the new object for you. My concern with doing this is now my factory classes are going to be a new free-for-all! I guess this may be ok as they are factory classes, but are there some rules to stick to when using factory pattern and DI, or am I going way off the mark here.

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  • Break a class in twain, or impose an interface for restricted access?

    - by bedwyr
    What's the best way of partitioning a class when its functionality needs to be externally accessed in different ways by different classes? Hopefully the following example will make the question clear :) I have a Java class which accesses a single location in a directory allowing external classes to perform read/write operations to it. Read operations return usage stats on the directory (e.g. available disk space, number of writes, etc.); write operations, obviously, allow external classes to write data to the disk. These methods always work on the same location, and receive their configuration (e.g. which directory to use, min disk space, etc.) from an external source (passed to the constructor). This class looks something like this: public class DiskHandler { public DiskHandler(String dir, int minSpace) { ... } public void writeToDisk(String contents, String filename) { int space = getAvailableSpace(); ... } public void getAvailableSpace() { ... } } There's quite a bit more going on, but this will do to suffice. This class needs to be accessed differently by two external classes. One class needs access to the read operations; the other needs access to both read and write operations. public class DiskWriter { DiskHandler diskHandler; public DiskWriter() { diskHandler = new DiskHandler(...); } public void doSomething() { diskHandler.writeToDisk(...); } } public class DiskReader { DiskHandler diskHandler; public DiskReader() { diskHandler = new DiskHandler(...); } public void doSomething() { int space = diskHandler.getAvailableSpace(...); } } At this point, both classes share the same class, but the class which should only read has access to the write methods. Solution 1 I could break this class into two. One class would handle read operations, and the other would handle writes: // NEW "UTILITY" CLASSES public class WriterUtil { private ReaderUtil diskReader; public WriterUtil(String dir, int minSpace) { ... diskReader = new ReaderUtil(dir, minSpace); } public void writeToDisk(String contents, String filename) { int = diskReader.getAvailableSpace(); ... } } public class ReaderUtil { public ReaderUtil(String dir, int minSpace) { ... } public void getAvailableSpace() { ... } } // MODIFIED EXTERNALLY-ACCESSING CLASSES public class DiskWriter { WriterUtil diskWriter; public DiskWriter() { diskWriter = new WriterUtil(...); } public void doSomething() { diskWriter.writeToDisk(...); } } public class DiskReader { ReaderUtil diskReader; public DiskReader() { diskReader = new ReaderUtil(...); } public void doSomething() { int space = diskReader.getAvailableSpace(...); } } This solution prevents classes from having access to methods they should not, but it also breaks encapsulation. The original DiskHandler class was completely self-contained and only needed config parameters via a single constructor. By breaking apart the functionality into read/write classes, they both are concerned with the directory and both need to be instantiated with their respective values. In essence, I don't really care to duplicate the concerns. Solution 2 I could implement an interface which only provisions read operations, and use this when a class only needs access to those methods. The interface might look something like this: public interface Readable { int getAvailableSpace(); } The Reader class would instantiate the object like this: Readable diskReader; public DiskReader() { diskReader = new DiskHandler(...); } This solution seems brittle, and prone to confusion in the future. It doesn't guarantee developers will use the correct interface in the future. Any changes to the implementation of the DiskHandler could also need to update the interface as well as the accessing classes. I like it better than the previous solution, but not by much. Frankly, neither of these solutions seems perfect, but I'm not sure if one should be preferred over the other. I really don't want to break the original class up, but I also don't know if the interface buys me much in the long run. Are there other solutions I'm missing?

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  • Swift Mailer email sending problem

    - by air
    i have downloaded Swift Mailer from their website and try to send simple email with following code <?php require_once 'lib/swift_required.php'; $transport = Swift_SmtpTransport::newInstance('smtp.example.org', 25) ->setUsername('your username') ->setPassword('your password') ; $mailer = Swift_Mailer::newInstance($transport); //Create a message $message = Swift_Message::newInstance('Wonderful Subject') ->setFrom(array('[email protected]' => 'John Doe')) ->setTo(array('[email protected]', '[email protected]' => 'A name')) ->setBody('Here is the message itself') ; //Send the message $result = $mailer->send($message); ? once i run the page it gives error Warning: fsockopen() [function.fsockopen]: php_network_getaddresses: getaddrinfo failed: No such host is known. in E:\web_sites\swift_mail\lib\classes\Swift\Transport\StreamBuffer.php on line 233 Warning: fsockopen() [function.fsockopen]: unable to connect to smtp.fiveocean.net:25 (php_network_getaddresses: getaddrinfo failed: No such host is known. ) in E:\web_sites\swift_mail\lib\classes\Swift\Transport\StreamBuffer.php on line 233 Fatal error: Uncaught exception 'Swift_TransportException' with message 'Connection could not be established with host smtp.fiveocean.net [php_network_getaddresses: getaddrinfo failed: No such host is known. #0]' in E:\web_sites\swift_mail\lib\classes\Swift\Transport\StreamBuffer.php:235 Stack trace: #0 E:\web_sites\swift_mail\lib\classes\Swift\Transport\StreamBuffer.php(70): Swift_Transport_StreamBuffer->_establishSocketConnection() #1 E:\web_sites\swift_mail\lib\classes\Swift\Transport\AbstractSmtpTransport.php(101): Swift_Transport_StreamBuffer->initialize(Array) #2 E:\web_sites\swift_mail\lib\classes\Swift\Mailer.php(74): Swift_Transport_AbstractSmtpTransport->start() #3 E:\web_sites\swift_mail\test.php(33): Swift_Mailer->send(Object(Swift_Message)) #4 {main} thrown in E:\web_sites\swift_mail\lib\classes\Swift\Transport\StreamBuffer.php on line 235 if i remove the line $result = $mailer->send($message); then page execute and no error message display, as soon as i add above line to send email, i got error. my outgoing server, port and user id & passwords are correct in my file. Thanks

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  • load class not in classpath dynamically in web application - without using custom classloader

    - by swdeveloper
    I am developing a web application. The web application generates java classes on the fly. For example it generates class com.people.Customer.java In my code, I dynamically compile this to get com.people.Customer.class and store in some directory say repository/com/people/Customer.class which is not on the classpath of my application server.My application server(I am using WebSphere Application Server/Apache Tomcat etc) picks up the classes from the WEB-INF/classes directory. The Classloader would use this to load the classes. After compilation I need to load this class so that it becomes accessible to other classes using it after its creation. 4.When I use Thread.currentThread().getContextClassLoader().loadClass(com.people.Customer) obviously the Classloader is not able to load the class, since its not on the classpath(not in WEB-INF/classes). Due to similar reasons, getResource(..) or getResourceAsStream(..) also does not work. I need a way to : Read the class Customer.class maybe as a stream (or any other way would do) and then load it. Following are the constraints: I cannot add the repository folder to the WEB-INF/classes folder. I cannot create a new Custom ClassLoader. If I create a new ClassLoader and this loads the class, it will not be accessible to its parent ClassLoader. Is there any way of achieving this? If not this, in the worse case, is there a way of overriding the default class loader with a custom class loader for web applications the same classloader should be used to load applications throughout entire lifecycle of my web application. Appreciate any solution :)

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  • Need advice on OOP philosophy

    - by David Jenings
    I'm trying to get the wheels turning on a large project in C#. My previous experience is in Delphi, where by default every form was created at applicaton startup and form references where held in (gasp) global variables. So I'm trying to adapt my thinking to a 100% object oriented environment, and my head is spinning just a little. My app will have a large collection of classes Most of these classes will only really need one instance. So I was thinking: static classes. I'm not really sure why, but much of what I've read here says that if my class is going to hold a state, which I take to mean any property values at all, I should use a singleton structure instead. Okay. But there are people out there who for reasons that escape me, think that singletons are evil too. None of these classes is in danger of being used anywhere except in this program. So they could certainly work fine as regular objects (vs singletons or static classes) Then there's the issue of interaction between objects. I'm tempted to create a Global class full of public static properties referencing the single instances of many of these classes. I've also considered just making them properties (static or instance, not sure which) of the MainForm. Then I'd have each of my classes be aware of the MainForm as Owner. Then the various objects could refer to each other as Owner.Object1, Owner.Object2, etc. I fear I'm running out of electronic ink, or at least taxing the patience of anyone kind enough to have stuck with me this long. I hope I have clearly explained my state of utter confusion. I'm just looking for some advice on best practices in my situation. All input is welcome and appreciated. Thanks in advance, David Jennings

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  • Class unloading in java

    - by java_geek
    When a classloader is garbage collected, are the classes loaded by it unloaded? When the JVM is running is verbose mode, all the loaded classes are o/p. Similarly will the JVM log when it unloads a class? I wrote a custom class loader to test this, but could not see any verbose log for unloading of the classes. CustomClassLoader loader = new CustomClassLoader(new URL[]{}, CustomClassLoader.class.getClassLoader()); loader.addURL("D:\workspace\ClassLoaderTest\implementation.jar"); Class c = null; try { c = Class.forName("Horse",false,loader); if (c != null) { try { Animal animal = (Animal)c.newInstance(); animal.eat(); } catch(Exception ex) { ex.printStackTrace(); } } } catch(Exception e) { e.printStackTrace(); } loader = null; byte[] b = new byte[58*1024*1024]; System.gc(); ClassLoadingMXBean clBean = ManagementFactory.getClassLoadingMXBean(); System.out.println("Number of classes currently loaded " + clBean.getLoadedClassCount()); System.out.println("Number of classes loaded totally " + clBean.getTotalLoadedClassCount()); System.out.println("Number of classes unloaded " + clBean.getUnloadedClassCount()); Even the ClassLoadingMXBean gives number of unloaded classes as 0. How can i know that a class is unloaded when the class loader is GCed?

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  • C++ traits question

    - by duli
    I have a templated class template <typename Data> class C { ..... } In most situations, I depend on the compiler to let me substitute types for Data. I call methods foo(), goo() on objects of type Data, so what I substitute needs to provide that. I now need to substitute int and string for my Data type. I do not want to specialize because the class is already too big and would require specializing each method (with only small code change). My options (please tell me if there are more) 1) I can provide wrapper classes around int and string which implement the methods foo(), goo() etc 2) provide a traits class traits that calls foo() or goo() on objects of classes that provide foo(),goo() (these are my present substitutable classes) and specialize these classes for int and string. Questions 1) what are the relative merits of 1 vs 2? 2) My traits classes will have static methods. Can a traits class have non-static methods as well? I see most traits classes define constants in the STL. 3) Do I make the traits classes global or should I pass them in as a template parameter for class C?

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  • More CPU cores may not always lead to better performance – MAXDOP and query memory distribution in spotlight

    - by sqlworkshops
    More hardware normally delivers better performance, but there are exceptions where it can hinder performance. Understanding these exceptions and working around it is a major part of SQL Server performance tuning.   When a memory allocating query executes in parallel, SQL Server distributes memory to each task that is executing part of the query in parallel. In our example the sort operator that executes in parallel divides the memory across all tasks assuming even distribution of rows. Common memory allocating queries are that perform Sort and do Hash Match operations like Hash Join or Hash Aggregation or Hash Union.   In reality, how often are column values evenly distributed, think about an example; are employees working for your company distributed evenly across all the Zip codes or mainly concentrated in the headquarters? What happens when you sort result set based on Zip codes? Do all products in the catalog sell equally or are few products hot selling items?   One of my customers tested the below example on a 24 core server with various MAXDOP settings and here are the results:MAXDOP 1: CPU time = 1185 ms, elapsed time = 1188 msMAXDOP 4: CPU time = 1981 ms, elapsed time = 1568 msMAXDOP 8: CPU time = 1918 ms, elapsed time = 1619 msMAXDOP 12: CPU time = 2367 ms, elapsed time = 2258 msMAXDOP 16: CPU time = 2540 ms, elapsed time = 2579 msMAXDOP 20: CPU time = 2470 ms, elapsed time = 2534 msMAXDOP 0: CPU time = 2809 ms, elapsed time = 2721 ms - all 24 cores.In the above test, when the data was evenly distributed, the elapsed time of parallel query was always lower than serial query.   Why does the query get slower and slower with more CPU cores / higher MAXDOP? Maybe you can answer this question after reading the article; let me know: [email protected].   Well you get the point, let’s see an example.   The best way to learn is to practice. To create the below tables and reproduce the behavior, join the mailing list by using this link: www.sqlworkshops.com/ml and I will send you the table creation script.   Let’s update the Employees table with 49 out of 50 employees located in Zip code 2001. update Employees set Zip = EmployeeID / 400 + 1 where EmployeeID % 50 = 1 update Employees set Zip = 2001 where EmployeeID % 50 != 1 go update statistics Employees with fullscan go   Let’s create the temporary table #FireDrill with all possible Zip codes. drop table #FireDrill go create table #FireDrill (Zip int primary key) insert into #FireDrill select distinct Zip from Employees update statistics #FireDrill with fullscan go  Let’s execute the query serially with MAXDOP 1. --Example provided by www.sqlworkshops.com --Execute query with uneven Zip code distribution --First serially with MAXDOP 1 set statistics time on go declare @EmployeeID int, @EmployeeName varchar(48),@zip int select @EmployeeName = e.EmployeeName, @zip = e.Zip from Employees e       inner join #FireDrill fd on (e.Zip = fd.Zip)       order by e.Zip option (maxdop 1) goThe query took 1011 ms to complete.   The execution plan shows the 77816 KB of memory was granted while the estimated rows were 799624.  No Sort Warnings in SQL Server Profiler.  Now let’s execute the query in parallel with MAXDOP 0. --Example provided by www.sqlworkshops.com --Execute query with uneven Zip code distribution --In parallel with MAXDOP 0 set statistics time on go declare @EmployeeID int, @EmployeeName varchar(48),@zip int select @EmployeeName = e.EmployeeName, @zip = e.Zip from Employees e       inner join #FireDrill fd on (e.Zip = fd.Zip)       order by e.Zip option (maxdop 0) go The query took 1912 ms to complete.  The execution plan shows the 79360 KB of memory was granted while the estimated rows were 799624.  The estimated number of rows between serial and parallel plan are the same. The parallel plan has slightly more memory granted due to additional overhead. Sort properties shows the rows are unevenly distributed over the 4 threads.   Sort Warnings in SQL Server Profiler.   Intermediate Summary: The reason for the higher duration with parallel plan was sort spill. This is due to uneven distribution of employees over Zip codes, especially concentration of 49 out of 50 employees in Zip code 2001. Now let’s update the Employees table and distribute employees evenly across all Zip codes.   update Employees set Zip = EmployeeID / 400 + 1 go update statistics Employees with fullscan go  Let’s execute the query serially with MAXDOP 1. --Example provided by www.sqlworkshops.com --Execute query with uneven Zip code distribution --Serially with MAXDOP 1 set statistics time on go declare @EmployeeID int, @EmployeeName varchar(48),@zip int select @EmployeeName = e.EmployeeName, @zip = e.Zip from Employees e       inner join #FireDrill fd on (e.Zip = fd.Zip)       order by e.Zip option (maxdop 1) go   The query took 751 ms to complete.  The execution plan shows the 77816 KB of memory was granted while the estimated rows were 784707.  No Sort Warnings in SQL Server Profiler.   Now let’s execute the query in parallel with MAXDOP 0. --Example provided by www.sqlworkshops.com --Execute query with uneven Zip code distribution --In parallel with MAXDOP 0 set statistics time on go declare @EmployeeID int, @EmployeeName varchar(48),@zip int select @EmployeeName = e.EmployeeName, @zip = e.Zip from Employees e       inner join #FireDrill fd on (e.Zip = fd.Zip)       order by e.Zip option (maxdop 0) go The query took 661 ms to complete.  The execution plan shows the 79360 KB of memory was granted while the estimated rows were 784707.  Sort properties shows the rows are evenly distributed over the 4 threads. No Sort Warnings in SQL Server Profiler.    Intermediate Summary: When employees were distributed unevenly, concentrated on 1 Zip code, parallel sort spilled while serial sort performed well without spilling to tempdb. When the employees were distributed evenly across all Zip codes, parallel sort and serial sort did not spill to tempdb. This shows uneven data distribution may affect the performance of some parallel queries negatively. For detailed discussion of memory allocation, refer to webcasts available at www.sqlworkshops.com/webcasts.     Some of you might conclude from the above execution times that parallel query is not faster even when there is no spill. Below you can see when we are joining limited amount of Zip codes, parallel query will be fasted since it can use Bitmap Filtering.   Let’s update the Employees table with 49 out of 50 employees located in Zip code 2001. update Employees set Zip = EmployeeID / 400 + 1 where EmployeeID % 50 = 1 update Employees set Zip = 2001 where EmployeeID % 50 != 1 go update statistics Employees with fullscan go  Let’s create the temporary table #FireDrill with limited Zip codes. drop table #FireDrill go create table #FireDrill (Zip int primary key) insert into #FireDrill select distinct Zip       from Employees where Zip between 1800 and 2001 update statistics #FireDrill with fullscan go  Let’s execute the query serially with MAXDOP 1. --Example provided by www.sqlworkshops.com --Execute query with uneven Zip code distribution --Serially with MAXDOP 1 set statistics time on go declare @EmployeeID int, @EmployeeName varchar(48),@zip int select @EmployeeName = e.EmployeeName, @zip = e.Zip from Employees e       inner join #FireDrill fd on (e.Zip = fd.Zip)       order by e.Zip option (maxdop 1) go The query took 989 ms to complete.  The execution plan shows the 77816 KB of memory was granted while the estimated rows were 785594. No Sort Warnings in SQL Server Profiler.  Now let’s execute the query in parallel with MAXDOP 0. --Example provided by www.sqlworkshops.com --Execute query with uneven Zip code distribution --In parallel with MAXDOP 0 set statistics time on go declare @EmployeeID int, @EmployeeName varchar(48),@zip int select @EmployeeName = e.EmployeeName, @zip = e.Zip from Employees e       inner join #FireDrill fd on (e.Zip = fd.Zip)       order by e.Zip option (maxdop 0) go The query took 1799 ms to complete.  The execution plan shows the 79360 KB of memory was granted while the estimated rows were 785594.  Sort Warnings in SQL Server Profiler.    The estimated number of rows between serial and parallel plan are the same. The parallel plan has slightly more memory granted due to additional overhead.  Intermediate Summary: The reason for the higher duration with parallel plan even with limited amount of Zip codes was sort spill. This is due to uneven distribution of employees over Zip codes, especially concentration of 49 out of 50 employees in Zip code 2001.   Now let’s update the Employees table and distribute employees evenly across all Zip codes. update Employees set Zip = EmployeeID / 400 + 1 go update statistics Employees with fullscan go Let’s execute the query serially with MAXDOP 1. --Example provided by www.sqlworkshops.com --Execute query with uneven Zip code distribution --Serially with MAXDOP 1 set statistics time on go declare @EmployeeID int, @EmployeeName varchar(48),@zip int select @EmployeeName = e.EmployeeName, @zip = e.Zip from Employees e       inner join #FireDrill fd on (e.Zip = fd.Zip)       order by e.Zip option (maxdop 1) go The query took 250  ms to complete.  The execution plan shows the 9016 KB of memory was granted while the estimated rows were 79973.8.  No Sort Warnings in SQL Server Profiler.  Now let’s execute the query in parallel with MAXDOP 0.  --Example provided by www.sqlworkshops.com --Execute query with uneven Zip code distribution --In parallel with MAXDOP 0 set statistics time on go declare @EmployeeID int, @EmployeeName varchar(48),@zip int select @EmployeeName = e.EmployeeName, @zip = e.Zip from Employees e       inner join #FireDrill fd on (e.Zip = fd.Zip)       order by e.Zip option (maxdop 0) go The query took 85 ms to complete.  The execution plan shows the 13152 KB of memory was granted while the estimated rows were 784707.  No Sort Warnings in SQL Server Profiler.    Here you see, parallel query is much faster than serial query since SQL Server is using Bitmap Filtering to eliminate rows before the hash join.   Parallel queries are very good for performance, but in some cases it can hinder performance. If one identifies the reason for these hindrances, then it is possible to get the best out of parallelism. I covered many aspects of monitoring and tuning parallel queries in webcasts (www.sqlworkshops.com/webcasts) and articles (www.sqlworkshops.com/articles). I suggest you to watch the webcasts and read the articles to better understand how to identify and tune parallel query performance issues.   Summary: One has to avoid sort spill over tempdb and the chances of spills are higher when a query executes in parallel with uneven data distribution. Parallel query brings its own advantage, reduced elapsed time and reduced work with Bitmap Filtering. So it is important to understand how to avoid spills over tempdb and when to execute a query in parallel.   I explain these concepts with detailed examples in my webcasts (www.sqlworkshops.com/webcasts), I recommend you to watch them. The best way to learn is to practice. To create the above tables and reproduce the behavior, join the mailing list at www.sqlworkshops.com/ml and I will send you the relevant SQL Scripts.   Register for the upcoming 3 Day Level 400 Microsoft SQL Server 2008 and SQL Server 2005 Performance Monitoring & Tuning Hands-on Workshop in London, United Kingdom during March 15-17, 2011, click here to register / Microsoft UK TechNet.These are hands-on workshops with a maximum of 12 participants and not lectures. For consulting engagements click here.   Disclaimer and copyright information:This article refers to organizations and products that may be the trademarks or registered trademarks of their various owners. Copyright of this article belongs to R Meyyappan / www.sqlworkshops.com. You may freely use the ideas and concepts discussed in this article with acknowledgement (www.sqlworkshops.com), but you may not claim any of it as your own work. This article is for informational purposes only; you use any of the suggestions given here entirely at your own risk.   Register for the upcoming 3 Day Level 400 Microsoft SQL Server 2008 and SQL Server 2005 Performance Monitoring & Tuning Hands-on Workshop in London, United Kingdom during March 15-17, 2011, click here to register / Microsoft UK TechNet.These are hands-on workshops with a maximum of 12 participants and not lectures. For consulting engagements click here.   R Meyyappan [email protected] LinkedIn: http://at.linkedin.com/in/rmeyyappan  

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  • More SQL Smells

    - by Nick Harrison
    Let's continue exploring some of the SQL Smells from Phil's list. He has been putting together. Datatype mis-matches in predicates that rely on implicit conversion.(Plamen Ratchev) This is a great example poking holes in the whole theory of "If it works it's not broken" Queries will this probably will generally work and give the correct response. In fact, without careful analysis, you probably may be completely oblivious that there is even a problem. This subtle little problem will needlessly complicate queries and slow them down regardless of the indexes applied. Consider this example: CREATE TABLE [dbo].[Page](     [PageId] [int] IDENTITY(1,1) NOT NULL,     [Title] [varchar](75) NOT NULL,     [Sequence] [int] NOT NULL,     [ThemeId] [int] NOT NULL,     [CustomCss] [text] NOT NULL,     [CustomScript] [text] NOT NULL,     [PageGroupId] [int] NOT NULL;  CREATE PROCEDURE PageSelectBySequence ( @sequenceMin smallint , @sequenceMax smallint ) AS BEGIN SELECT [PageId] , [Title] , [Sequence] , [ThemeId] , [CustomCss] , [CustomScript] , [PageGroupId] FROM [CMS].[dbo].[Page] WHERE Sequence BETWEEN @sequenceMin AND @SequenceMax END  Note that the Sequence column is defined as int while the sequence parameter is defined as a small int. The problem is that the database may have to do a lot of type conversions to evaluate the query. In some cases, this may even negate the indexes that you have in place. Using Correlated subqueries instead of a join   (Dave_Levy/ Plamen Ratchev) There are two main problems here. The first is a little subjective, since this is a non-standard way of expressing the query, it is harder to understand. The other problem is much more objective and potentially problematic. You are taking much of the control away from the optimizer. Written properly, such a query may well out perform a corresponding query written with traditional joins. More likely than not, performance will degrade. Whenever you assume that you know better than the optimizer, you will most likely be wrong. This is the fundmental problem with any hint. Consider a query like this:  SELECT Page.Title , Page.Sequence , Page.ThemeId , Page.CustomCss , Page.CustomScript , PageEffectParams.Name , PageEffectParams.Value , ( SELECT EffectName FROM dbo.Effect WHERE EffectId = dbo.PageEffects.EffectId ) AS EffectName FROM Page INNER JOIN PageEffect ON Page.PageId = PageEffects.PageId INNER JOIN PageEffectParam ON PageEffects.PageEffectId = PageEffectParams.PageEffectId  This can and should be written as:  SELECT Page.Title , Page.Sequence , Page.ThemeId , Page.CustomCss , Page.CustomScript , PageEffectParams.Name , PageEffectParams.Value , EffectName FROM Page INNER JOIN PageEffect ON Page.PageId = PageEffects.PageId INNER JOIN PageEffectParam ON PageEffects.PageEffectId = PageEffectParams.PageEffectId INNER JOIN dbo.Effect ON dbo.Effects.EffectId = dbo.PageEffects.EffectId  The correlated query may just as easily show up in the where clause. It's not a good idea in the select clause or the where clause. Few or No comments. This one is a bit more complicated and controversial. All comments are not created equal. Some comments are helpful and need to be included. Other comments are not necessary and may indicate a problem. I tend to follow the rule of thumb that comments that explain why are good. Comments that explain how are bad. Many people may be shocked to hear the idea of a bad comment, but hear me out. If a comment is needed to explain what is going on or how it works, the logic is too complex and needs to be simplified. Comments that explain why are good. Comments may explain why the sql is needed are good. Comments that explain where the sql is used are good. Comments that explain how tables are related should not be needed if the sql is well written. If they are needed, you need to consider reworking the sql or simplify your data model. Use of functions in a WHERE clause. (Anil Das) Calling a function in the where clause will often negate the indexing strategy. The function will be called for every record considered. This will often a force a full table scan on the tables affected. Calling a function will not guarantee that there is a full table scan, but there is a good chance that it will. If you find that you often need to write queries using a particular function, you may need to add a column to the table that has the function already applied.

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  • C# PredicateBuilder Entities: The parameter 'f' was not bound in the specified LINQ to Entities quer

    - by Neothor
    I needed to build a dynamic filter and I wanted to keep using entities. Because of this reason I wanted to use the PredicateBuilder from albahari. I created the following code: var invoerDatums = PredicateBuilder.True<OnderzoeksVragen>(); var inner = PredicateBuilder.False<OnderzoeksVragen>(); foreach (var filter in set.RapportInvoerFilter.ToList()) { if(filter.IsDate) { var date = DateTime.Parse(filter.Waarde); invoerDatums = invoerDatums.Or(o => o.Van >= date && o.Tot <= date); } else { string temp = filter.Waarde; inner = inner.Or(o => o.OnderzoekType == temp); } } invoerDatums = invoerDatums.And(inner); var onderzoeksVragen = entities.OnderzoeksVragen .AsExpandable() .Where(invoerDatums) .ToList(); When I ran the code there was only 1 filter which wasn't a date filter. So only the inner predicate was filled. When the predicate was executed I got the following error. The parameter 'f' was not bound in the specified LINQ to Entities query expression. While searching for an answer I found the following page. But this is already implemented in the LINQKit. Does anyone else experienced this error and know how to solve it?

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  • Sync Framework - In order to evaluate an indexed property, the property must be qualified and the ar

    - by Khor
    I trying to do a snapshot between SQLCE 3.5 SP1 and SQL Server 2008 by using the sync framework. I received a inner exception stated that "{"Unable to enumerate changes at the DbServerSyncProvider for table 'ArInvoice' in synchronization group 'ArInvoiceSyncTableSyncGroup'."}". The inner text for the inner exception stated that "Timeout expired. The timeout period elapsed prior to completion of the operation or the server is not responding.". And the item for the inner exception indicated that "In order to evaluate an indexed property, the property must be qualified and the arguments must be explicitly supplied by the user.". What is going wrong? Any setting i miss out?

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  • Multi-statement Table Valued Function vs Inline Table Valued Function

    - by AndyC
    ie: CREATE FUNCTION MyNS.GetUnshippedOrders() RETURNS TABLE AS RETURN SELECT a.SaleId, a.CustomerID, b.Qty FROM Sales.Sales a INNER JOIN Sales.SaleDetail b ON a.SaleId = b.SaleId INNER JOIN Production.Product c ON b.ProductID = c.ProductID WHERE a.ShipDate IS NULL GO versus: CREATE FUNCTION MyNS.GetLastShipped(@CustomerID INT) RETURNS @CustomerOrder TABLE (SaleOrderID INT NOT NULL, CustomerID INT NOT NULL, OrderDate DATETIME NOT NULL, OrderQty INT NOT NULL) AS BEGIN DECLARE @MaxDate DATETIME SELECT @MaxDate = MAX(OrderDate) FROM Sales.SalesOrderHeader WHERE CustomerID = @CustomerID INSERT @CustomerOrder SELECT a.SalesOrderID, a.CustomerID, a.OrderDate, b.OrderQty FROM Sales.SalesOrderHeader a INNER JOIN Sales.SalesOrderHeader b ON a.SalesOrderID = b.SalesOrderID INNER JOIN Production.Product c ON b.ProductID = c.ProductID WHERE a.OrderDate = @MaxDate AND a.CustomerID = @CustomerID RETURN END GO Is there an advantage to using one over the other? Is there certain scenarios when one is better than the other or are the differences purely syntactical? I realise the 2 example queries are doing different things but is there a reason I would write them in that way? Reading about them and the advantages/differences haven't really been explained. Thanks

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  • WPF Dispatcher.UnhandledException within a ShowDialog call.

    - by Eric
    It appears that ShowDialog() invokes the Dispatcher message handling loop within. Thus, you have a stack that looks something like: Outer-most Dispatcher message loop ... x.ShowDialog() Inner Dispatcher message loop ... I am using the Dispatcher.UnhandledException to catch exceptions not handled by my code. However, it appears that the Inner Dispatcher message loop, above, is undesirably catching exceptions that my code would catch. Example: Outer-most Dispatcher message loop try/catch FooException ... x.ShowDialog() Inner Dispatcher message loop ... throw FooException What I would like is for the thrown FooException to get caught by the try/catch. However. It gets caught first by the (inner) Dispatcher.UnhandledException. I see there are ways to filter the exception. However, those filters will apply to both the inner and outer most handlers. What I am looking for is to have my Dispatcher.UnhandledException code run only on the outer-most dispatcher message loop. Does that make sense? I could, of course, reflect the call stack from within my handler to see if this is the outer-most dispatcher, but that seems a bit fragile. Other ideas? Thanks! Eric

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  • mySQL :syntax using in C#

    - by Meko
    Hi. I am using in C# MYsql .I have query that works if I run on MySql Workbench ,but in C# it does not return any value also does not give ant error too.There is only one different using on Mysql I use before table name databaseName.tableName , but in C# I think it doesn`t necessary. This is part of query which does not return anything. "(select Lesson_Name from schedule where Group_NO = (select Group_NO from sinif inner join student ON sinif.Group_ID=student.Group_ID where Student_Name=(?Student))"+ " And Day_Name =(select Day_Name from day inner join date ON day.Day_ID=date.DayName where Date=(?Date))" + "And Lesson_Time= (select Lesson_Time from clock where Lesson_Time <= (?Time)order by Lesson_Time DESC limit 0, 1) " + " And Week_NO = (select Week_NO from week inner join date ON week.Week_ID=date.Week_ID where Date=(?Date))) And Here all codes which executes when user click button. private void check_B_Click(object sender, EventArgs e) { connection.Open(); for (int i = 0; i < existingStudents.Count; i++) { MySqlCommand cmd1 = new MySqlCommand("select Student_Name,Student_Surname,Student_MacAddress from student ", connection); MySqlCommand cmd2 = new MySqlCommand("insert into check_list (Student,Mac_Address,Date,Time,Lesson_Name)"+ "values((?Student),(?MacAddress),(?Date),(?Time),"+ "(select Lesson_Name from schedule where Group_NO = (select Group_NO from sinif inner join student ON sinif.Group_ID=student.Group_ID where Student_Name=(?Student))"+ " And Day_Name =(select Day_Name from day inner join date ON day.Day_ID=date.DayName where Date=(?Date))" + "And Lesson_Time= (select Lesson_Time from clock where Lesson_Time <= (?Time)order by Lesson_Time DESC limit 0, 1) " + " And Week_NO = (select Week_NO from week inner join date ON week.Week_ID=date.Week_ID where Date=(?Date))))", connection); MySqlParameter param1 = new MySqlParameter(); param1.ParameterName = "?Student"; reader = cmd1.ExecuteReader(); if (reader.HasRows) while (reader.Read()) { if (reader["Student_MacAddress"].ToString() == existingStudentsMac[i].ToString()) param1.Value = reader["Student_Name" ]+" "+reader["Student_Surname"]; } reader.Close(); MySqlParameter param2 = new MySqlParameter(); param2.ParameterName = "?MacAddress"; param2.Value = existingStudentsMac[i]; MySqlParameter param3 = new MySqlParameter(); param3.ParameterName = "?Date"; param3.Value = DateTime.Today.Date; MySqlParameter param4 = new MySqlParameter(); param4.ParameterName = "?Time"; param4.Value = DateTime.Now.ToString("HH:mm"); cmd2.Parameters.Add(param1); cmd2.Parameters.Add(param2); cmd2.Parameters.Add(param3); cmd2.Parameters.Add(param4); cmd2.ExecuteNonQuery(); } connection.Close(); MessageBox.Show("Sucsess :)"); }

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  • Scheme Formatting Help

    - by Logan
    I've been working on a project for school that takes functions from a class file and turns them into object/classes. The assignment is all about object oriented programming in scheme. My problem however is that my code doesn't format right. The output it gives me whenever I give it a file to pass in wraps the methods of the class in a list, making it so that the class never really gets declared. I can't for the life of me figure out how to get the parenthesis wrapping the method list to remove. I would really appreciate any help. Below is the code and the class file. ;;;; PART1 --- A super-easy set of classes. Just models points and lines. Tests all of the ;; basics of class behavior without touching on anything particularly complex. (class pointInstance (parent:) (constructor_args:) (ivars: (myx 1) (myy 2)) (methods: (getx () myx) (gety () myy) (setx (x) (set! myx x)) (show () (begin (display "[") (display myx) (display ",") (display myy) (display "]"))) )) (require (lib "trace.ss")) ;; Continue reading until you hit the end of the file, all the while ;; building a list with the contents (define load-file (lambda (port) (let ((rec (read port))) (if (eof-object? rec) '() (cons rec (load-file port)))))) ;; Open a port based on a file name using open-input-file (define (load fname) (let ((fport (open-input-file fname))) (load-file fport))) ;(define lis (load "C:\\Users\\Logan\\Desktop\\simpletest.txt")) ;(define lis (load "C:\\Users\\Logan\\Desktop\\complextest.txt")) (define lis (load "C:\\Users\\Logan\\Desktop\\pointinstance.txt")) ;(display (cdaddr (cdddar lis))) (define makeMethodList (lambda (listToMake retList) ;(display listToMake) (cond [(null? listToMake) retList ;(display "The list passed in to parse was null") ] [else (makeMethodList (cdr listToMake) (append retList (list (getMethodLine listToMake)))) ] ) )) ;(trace makeMethodList) ;this works provided you just pass in the function line (define getMethodLine (lambda (functionList) `((eq? (car msg) ,(caar functionList)) ,(caddar functionList)))) (define load-classes (lambda paramList (cond [(null? paramList) (display "Your parameters are null, man.")] [(null? (car paramList))(display "Done creating class definitions.")] [(not (null? (car paramList))) (begin (let* ((className (cadaar paramList)) (classInstanceVars (cdaddr (cddaar paramList))) (classMethodList (cdr (cadddr (cddaar paramList)))) (desiredMethodList (makeMethodList classMethodList '())) ) ;(display "Classname: ") ;(display className) ;(newline)(newline) ;(display "Class Instance Vars: ") ;(display classInstanceVars) ;(newline)(newline) ;(display "Class Method List: ") ;(display classMethodList) ;(newline) ;(display "Desired Method List: ") ;(display desiredMethodList)) ;(newline)(newline) ;---------------------------------------------------- ;do not delete the below code!` `(define ,className (let ,classInstanceVars (lambda msg ;return the function list here (cond ,(makeMethodList classMethodList '()))) )) ;--------------------------------------------------- ))] ) )) (load-classes lis) ;(load-classes lis) ;(load-classes-helper lis) ;(load-classes "simpletest.txt") ;(load-classes "complextest.txt") ;method list ;(display (cdr (cadddr (cddaar <class>))))

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  • MySQL Query GROUP_CONCAT Over Multiple Rows

    - by PeteGO
    I'm getting name and address data out of generic question / answer data to create some kind of normalised reporting database. The query I've got uses group_concat and works for individual sets of questions but not for multiple sets. I've tried to simplify what I'm doing by using just forename and surname and just 3 records, 2 for 1 person and 1 for another. In reality though there are more than 300,000 records. Example of results with qs.Id = 1. QuestionSetId Forename Surname ------------------------------------------------------- 1 Bob Jones Example of results with qs.Id IN (1, 2, 3). QuestionSetId Forename Surname ------------------------------------------------------- 3 Bob,Bob,Frank Jones,Jones,Smith What I would like to see for qs.Id IN (1, 2, 3). QuestionSetId Forename Surname ------------------------------------------------------- 1 Bob Jones 2 Bob Jones 3 Frank Smith So how can I make the 2nd example return a separate row for each set of name and address information? I realise the current way the data is stored is "questionable" but I cannot change the way the data is stored. I can get sets of individual answers but not sure how to combine the others. My simplified Schema that I cannot change: CREATE TABLE StaticQuestion ( Id INT NOT NULL, StaticText VARCHAR(500) NOT NULL); CREATE TABLE Question ( Id INT NOT NULL, Text VARCHAR(500) NOT NULL); CREATE TABLE StaticQuestionQuestionLink ( Id INT NOT NULL, StaticQuestionId INT NOT NULL, QuestionId INT NOT NULL, DateEffective DATETIME NOT NULL); CREATE TABLE Answer ( Id INT NOT NULL, Text VARCHAR(500) NOT NULL); CREATE TABLE QuestionSet ( Id INT NOT NULL, DateEffective DATETIME NOT NULL); CREATE TABLE QuestionAnswerLink ( Id INT NOT NULL, QuestionSetId INT NOT NULL, QuestionId INT NOT NULL, AnswerId INT NOT NULL, StaticQuestionId INT NOT NULL); Some example data for only forename and surname. INSERT INTO StaticQuestion (Id, StaticText) VALUES (1, 'FirstName'), (2, 'LastName'); INSERT INTO Question (Id, Text) VALUES (1, 'What is your first name?'), (2, 'What is your forename?'), (3, 'What is your Surname?'); INSERT INTO StaticQuestionQuestionLink (Id, StaticQuestionId, QuestionId, DateEffective) VALUES (1, 1, 1, '2001-01-01'), (2, 1, 2, '2008-08-08'), (3, 2, 3, '2001-01-01'); INSERT INTO Answer (Id, Text) VALUES (1, 'Bob'), (2, 'Jones'), (3, 'Bob'), (4, 'Jones'), (5, 'Frank'), (6, 'Smith'); INSERT INTO QuestionSet (Id, DateEffective) VALUES (1, '2002-03-25'), (2, '2009-05-05'), (3, '2009-08-06'); INSERT INTO QuestionAnswerLink (Id, QuestionSetId, QuestionId, AnswerId, StaticQuestionId) VALUES (1, 1, 1, 1, 1), (2, 1, 3, 2, 2), (3, 2, 2, 3, 1), (4, 2, 3, 4, 2), (5, 3, 2, 5, 1), (6, 3, 3, 6, 2); Just in case SQLFiddle is down here are the 3 queries from the examples I've linked to: 1: - working query but only on 1 set of data. SELECT MAX(QuestionSetId) AS QuestionSetId, GROUP_CONCAT(Forename) AS Forename, GROUP_CONCAT(Surname) AS Surname FROM (SELECT x.QuestionSetId, CASE x.StaticQuestionId WHEN 1 THEN Text END AS Forename, CASE x.StaticQuestionId WHEN 2 THEN Text END AS Surname FROM (SELECT (SELECT link.StaticQuestionId FROM StaticQuestionQuestionLink link WHERE link.Id = qa.QuestionId AND link.DateEffective <= qs.DateEffective AND link.StaticQuestionId IN (1, 2) ORDER BY link.DateEffective DESC LIMIT 1) AS StaticQuestionId, a.Text, qa.QuestionSetId FROM QuestionSet qs INNER JOIN QuestionAnswerLink qa ON qs.Id = qa.QuestionSetId INNER JOIN Answer a ON qa.AnswerId = a.Id WHERE qs.Id IN (1)) x) y 2: - working query but undesired results on multiple sets of data. SELECT MAX(QuestionSetId) AS QuestionSetId, GROUP_CONCAT(Forename) AS Forename, GROUP_CONCAT(Surname) AS Surname FROM (SELECT x.QuestionSetId, CASE x.StaticQuestionId WHEN 1 THEN Text END AS Forename, CASE x.StaticQuestionId WHEN 2 THEN Text END AS Surname FROM (SELECT (SELECT link.StaticQuestionId FROM StaticQuestionQuestionLink link WHERE link.Id = qa.QuestionId AND link.DateEffective <= qs.DateEffective AND link.StaticQuestionId IN (1, 2) ORDER BY link.DateEffective DESC LIMIT 1) AS StaticQuestionId, a.Text, qa.QuestionSetId FROM QuestionSet qs INNER JOIN QuestionAnswerLink qa ON qs.Id = qa.QuestionSetId INNER JOIN Answer a ON qa.AnswerId = a.Id WHERE qs.Id IN (1, 2, 3)) x) y 3: - working query on multiple sets of data only on 1 field (answer) though. SELECT qs.Id AS QuestionSet, a.Text AS Answer FROM QuestionSet qs INNER JOIN QuestionAnswerLink qalink ON qs.Id = qalink.QuestionSetId INNER JOIN StaticQuestionQuestionLink sqqlink ON qalink.QuestionId = sqqlink.QuestionId INNER JOIN Answer a ON qalink.AnswerId = a.Id WHERE sqqlink.StaticQuestionId = 1 /* FirstName */ AND sqqlink.DateEffective = (SELECT DateEffective FROM StaticQuestionQuestionLink WHERE StaticQuestionId = 1 AND DateEffective <= qs.DateEffective ORDER BY DateEffective DESC LIMIT 1)

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  • Dynamic SQL To Dynamic LINQ in VB.NET with MS SQL Server 2008

    - by user337501
    I dread asking this question, because with what I've read so far I understand im gonna have to cram a lotta new things into my head. In spite of all the similiar questions(and the wide variety of answers) I thought I'd ask as nothing I've read tailors to what I need specifically enough. I need to represent the following query using LINQ: DECLARE @PurchasedInventoryItemID Int = 2 DECLARE @PurchasedInventorySectionID Int = 0 DECLARE @PurchasedInventoryItem_PurchasingCategoryID Int = 3 DECLARE @PurchasedInventorySection_PurchasingCategoryID Int = 0 DECLARE @IsActive Bit = 1 DECLARE @PropertyID Int = 2 DECLARE @PropertyValue nvarchar(1000) = 'Granny Smith' --Property1, Property2, Property3 ... SELECT O.PurchasedInventoryObjectID, O.PurchasedInventoryObjectName, O.PurchasedInventoryConjunctionID, O.Summary, O.Count, O.PropertyCount, O.IsActive FROM tblPurchasedInventoryObject As O INNER JOIN tblPurchasedInventoryConjunction As C ON C.PurchasedInventoryConjunctionID = O.PurchasedInventoryConjunctionID INNER JOIN tblPurchasedInventoryItem As I ON I.PurchasedInventoryItemID = C.PurchasedInventoryItemID INNER JOIN tblPurchasedInventorySection As S ON S.PurchasedInventorySectionID = C.PurchasedInventorySectionID INNER JOIN tblPurchasedInventoryPropertyMap as M ON M.PurchasedInventoryObjectID = O.PurchasedInventoryObjectID INNER JOIN tblPropertyValue As V ON V.PropertyValueID = M.PropertyValueID WHERE I.PurchasedInventoryItemID = @PurchasedInventoryItemID AND S.PurchasedInventorySectionID = @PurchasedInventorySectionID AND I.PurchasingCategoryID = @PurchasedInventoryItem_PurchasingCategoryID AND S.PurchasingCategoryID = @PurchasedInventorySection_PurchasingCategoryID AND O.IsActive = @IsActive AND V.PropertyID = @PropertyID AND V.Value = @PropertyValue Now, I know that a query in .NET doesnt look like this, this is my test in the SQL Design Studio. Naturally VB.NET variables will be used in place of the SQL local variables. My problem is this: All of the conditions after "WHERE" are optional. In that a query might be made that uses one, some, all, or none of the conditions. V.PropertyID and V.Value can also appear any number of times. In VB.NET I can make this query easy enough by simply concatenating strings, and using a loop to append the "V.PropertyID/V.Value" conditions. I can also make a Stored Procedure in MS SQL, which is easy enough. However, I want to accomplish this using LINQ. If anyone could direct me, I would be most appreciative.

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  • How do i write this jpql query?

    - by Nitesh Panchal
    Hello, Say i have 5 tables, tblBlogs tblBlogPosts tblBlogPostComment tblUser tblBlogMember BlogId BlogPostsId BlogPostCommentId UserId BlogMemberId BlogTitle BlogId CommentText FirstName UserId PostTitle BlogPostsId BlogId BlogMemberId Now i want to retrieve only those blogs and posts for which blogMember has actually commented. So in short, how do i write this plain old sql :- Select b.BlogTitle, bp.PostTitle, bpc.CommentText from tblBlogs b Inner join tblBlogPosts bp on b.BlogId = bp.BlogId Inner Join tblBlogPostComment bpc on bp.BlogPostsId = bpc.BlogPostsId Inner Join tblBlogMember bm On bpc.BlogMemberId = bm.BlogMemberId Where bm.UserId = 1; As you can see, everything is Inner join, so only that row will be retrieved for which the user has commented on some post of some blog. So, suppose he has joined 3 blogs whose ids are 1,2,3 (The blogs which user has joined are in tblBlogMembers) but the user has only commented in blog 2 (of say BlogPostId = 1). So that row will be retrieved and 1,3 won't as it is Inner Join. How do i write this kind of query in jpql? In jpql, we can only write simple queries like say :- Select bm.blogId from tblBlogMember Where bm.UserId = objUser; Where objUser is supplied using :- em.find(User.class,1); Thus once we get all blogs(Here blogId represents a blog object) which user has joined, we can loop through and do all fancy things. But i don't want to fall in this looping business and write all this things in my java code. Instead, i want to leave that for database engine to do. So, how do i write the above plain sql into jpql? and what type of object the jpql query will return? because i am only selecting few fields from all table. In which class should i typecast the result to? I think i posted my requirement correctly, if i am not clear please let me know. Thanks in advance :).

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  • How to set WCF threads to schedual differently

    - by Gilad
    Hi, I'm running a winservice that has 2 main objectives. Execute/Handle exposed webmethods. Run Inner processes that consume allot of CPU. The problem is that when I execute many inner processes |(as tasks) that are queued to the threadpool or taskpool, the execution of the webmethods takes much more time as WCF also queues its executions to the same threadpool. This even happens when setting the inner processes task priority to lowest and setting the webmethods thread priority to heights. I hoped that Framework 4.0 would improve this, and they have, but still it takes quite allot of time for the system to handle the WCF queued tasks if the CPU is handling other inner tasks. Is it possible to change the Threadpool that WCF uses to a different one? Is it possible to manually change the task queue (global task queue, local task queue). Is it possible to manually handle 2 task queues that behave differently ? Any help in the subject would be appropriated. Gilad.

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