Concurrency Mechanism In Software Engineering

Multi threading C application with SQL Server database calls. Overview. The root of your problem is that the L2. S Data. Context, like the Entity Frameworks Object. Context, is not thread safe. Distributed+system+characteristics+%2F+advantages.jpg' alt='Concurrency Mechanism In Software Engineering' title='Concurrency Mechanism In Software Engineering' />As explained in this MSDN forum exchange, support for asynchronous operations in the. NET ORM solutions is still pending as of. NET 4. 0 youll have to roll your own solution, which as youve discovered isnt always easy to do when your framework assume single threadedness. Ill take this opportunity to note that L2. S is built on top of ADO. NET, which itself fully supports asynchronous operation personally, I would much prefer to deal directly with that lower layer and write the SQL myself, just to make sure that I fully understood what was transpiring over the network. SQL Server Solution That being said, I have to ask must this be a C solutionIf you can compose your solution out of a set of insertupdate statements, you can just send over the SQL directly and your threading and performance problems vanish. It seems to me that your problems are related not to the actual data transformations to be made, but center around making them performant from. NET. If. NET is removed from the equation, your task becomes simpler. After all, the best solution is often the one that has you writing the smallest amount of code, right Even if your updateinsert logic cant be expressed in a strictly set relational manner, SQL Server does have a built in mechanism for iterating over records and performing logic while they are justly maligned for many use cases, cursors may in fact be appropriate for your task. If this is a task that has to happen repeatedly, you could benefit greatly from coding it as a stored procedure. SQL brings its own problems like lock escalation and index usage that youll have to contend with. C Solution. Of course, it may be that doing this in SQL is out of the question maybe your codes decisions depend on data that comes from elsewhere, for example, or maybe your project has a strict no SQL allowed convention. Concurrency Mechanism In Software Engineering' title='Concurrency Mechanism In Software Engineering' />You mention some typical multithreading bugs, but without seeing your code I cant really be helpful with them specifically. Doing this from C is obviously viable, but you need to deal with the fact that a fixed amount of latency will exist for each and every call you make. You can mitigate the effects of network latency by using pooled connections, enabling multiple active result sets, and using the asynchronous BeginEnd methods for executing your queries. Even with all of those, you will still have to accept that there is a cost to shipping data from SQL Server to your application. One of the best ways to keep your code from stepping all over itself is to avoid sharing mutable data between threads as much as possible. That would mean not sharing the same Data. Context across multiple threads. The next best approach is to lock critical sections of code that touch the shared data lock blocks around all Data. Classtested and coherent, this groundbreaking new textbook teaches webera information retrieval, including web search and the related areas of text classification. ACM Learning Webinars. ACM keeps you at the cutting edge of the latest technical and technological developments with our ACM Learning Webinar series. I have a SQL Server database with 500,000 records in table main. There are also three other tables called child1, child2, and child3. The many to many relationships. Concurrency Mechanism In Software Engineering' title='Concurrency Mechanism In Software Engineering' />Software design is a phase in software engineering, in which a blueprint is developed to serve as a base for constructing the software system. Free SAP Hybris, FlexBox, Axure RP, OpenShift, Apache Bench, qTest, TestLodge, Power BI, Jython, Financial Accounting, text and video tutorials for UPSC, IAS, PCS. Context access, from the first read to the final write. That approach might just obviate the benefits of multithreading entirely you can likely make your locking more fine grained, but be ye warned that this is a path of pain. Far better is to keep your operations separate from each other entirely. If you can partition your logic across main records, thats ideal that is to say, as long as there arent relationships between the various child tables, and as long as one record in main doesnt have implications for another, you can split your operations across multiple threads like this private IListlt int Get. Main. Ids. using var context new My. Galaxy Angel Eternal Lovers 1.10 Patch on this page. Data. Context. Main. Selectm m. Id. To. List. private void Fix. Up. Single. Recordint main. Record. Id. using var local. Context new My. Data. Context. Context. Main. First. Or. Defaultm m. Nginx pronounced engine x is a free open source web server written by Igor Sysoev, a Russian software engineer. Since its public launch in 2004, nginx has focused. Vol. 7, No. 3, May, 2004. Mathematical and Natural Sciences. Study on Bilinear Scheme and Application to Threedimensional Convective Equation Itaru Hataue and Yosuke. Software engineering is more a practice in archeology than it is in building. As an industry, we undervalue storytelling and focus too much on artifacts and tools and. Concurrency Mechanism In Software Engineering' title='Concurrency Mechanism In Software Engineering' />Id main. Record. Id. if main null. One. Quality in main. Child. One. Qualities. If child one is not found, create it. Create the relationship if needed. Repeat for Child. Two and Child. Three. Context. Save. Changes. Fix. Up. Main. var ids Get. Main. Ids. foreach var id in ids. Id id Avoid closing over an iteration member. Thread. Pool. Queue. User. Work. Itemdelegate Fix. Up. Single. Recordid. Obviously this is as much a toy example as the pseudocode in your question, but hopefully it gets you thinking about how to scope your tasks such that there is no or minimal shared state between them. That, I think, will be the key to a correct C solution. If youre seeing data consistency issues, Id advise enforcing transaction semantics you can do this by using a System. Transactions. Transaction. Scope add a reference to System. Transactions. Alternately, you might be able to do this on an ADO. NET level by accessing the inner connection and calling Begin. Transaction on it or whatever the Data. Connection method is called. You also mention deadlocks. That youre battling SQL Server deadlocks indicates that the actual SQL queries are stepping on each others toes. Without knowing what is actually being sent over the wire, its difficult to say in detail whats happening and how to fix it. Suffice to say that SQL deadlocks result from SQL queries, and not necessarily from C threading constructs you need to examine what exactly is going over the wire. My gut tells me that if each main record is truly independent of the others, then there shouldnt be a need for row and table locks, and that Linq to SQL is likely the culprit here. You can get a dump of the raw SQL emitted by L2. S in your code by setting the Data. Context. Log property to something e. Console. Out. Though Ive never personally used it, I understand the LINQPad offers L2. S facilities and you may be able to get at the SQL there, too. SQL Server Management Studio will get you the rest of the way there using the Activity Monitor, you can watch for lock escalation in real time. Using the Query Analyzer, you can get a view of exactly how SQL Server will execute your queries. With those, you should be able to get a good notion of what your code is doing server side, and in turn how to go about fixing it.