We have a large (about 580,000 loc) application which in Delphi 2006 builds (on my machine) in around 20 seconds. When you have build times in seconds, you tend to use the compiler as a tool. i.e. write a little code, build, write some more code and build some more etc etc As we move some of our stuff over to C#, does anyone have a compa...
What is the worst (due to either prevalence or severity) example of abstraction inversion that you see in programming today? For those of you who are not familiar with the concept, abstraction inversion is implementing low-level constructs on top of high-level constructs. More precisely, assume you have constructs A and B. B is implem...
someone has an idea how can I do that ? thanks ...
I have a body of text that I have to scan and each line contains at least 2 and sometimes four parts of information. The problem is that each line can be 1 out of 15-20 different actions. in ruby the current code looks somewhat like this: text.split("\n").each do |line| #around 20 times.. .............. expressions['actions']...
We are running a website using Active Server Pages & COM+ components. The ASP pages call COM+ components which in turn communicates with external systems and respond to ASP page requests. We find that the application becomes slow over a period of time and requires restarts (like in couple of days). The website runs on good hardware and ...
The performance of a Direct3D application seems to be significantly better in full screen mode compared to windowed mode. What are the technical reasons behind this? I guess it has something to do with the fact that a full screen application can gain exclusive control for the display. But why the application cannot gain exclusive contro...
Hi folks, in the System.Linq namespace, we can now extend our IEnumerable's to have theAny() and Count() extension methods. I was told recently that if i want to check that a collection contains 1 or more items inside it, I should use the .Any() extension method instead of the .Count() > 0 extension method because the .Count() extensio...
Is there any performance gain using a CTE over a derived table? ...
I am porting an existing application to C# and want to improve performance wherever possible. Many existing loop counters and array references are defined as System.UInt32, instead of the Int32 I would have used. Is there any significant performance difference for using UInt32 vs Int32? ...
I'm have a ADO DataSet that I'm loading from its XML file via ReadXml. The data and the schema are in separate files. Right now, it takes close to 13 seconds to load this DataSet. I can cut this to 700 milliseconds if I don't read the DataSet's schema and just let ReadXml infer the schema, but then the resulting DataSet doesn't contai...
I have a 2D image randomly and sparsely scattered with pixels. given a point on the image, I need to find the distance to the closest pixel that is not in the background color (black). What is the fastest way to do this? The only method I could come up with is building a kd-tree for the pixels. but I would really want to avoid such ex...
I keep seeing people say that exceptions are slow but I never see any proof. So instead of asking if they are I will ask how do exceptions work behind the scene so I can make a decisions of when to use them and if they are slow. From what I know exceptions are the same thing as doing a bunch of return but it also checks when it needs to...
I recently completed development of a mid-traficked(?) website (peak 60k hits/hour), however, the site only needs to be updated once a minute - and achieving the required performance can be summed up by a single word: "caching". For a site like SO where the data feeding the site changes all the time, I would imagine a different approach...
Are there any good (preferably free) tools out there? Can they give accurate estimates that reflect production results when the app goes live? ...
We all know that premature optimization is the root of all evil because it leads to unreadable/unmaintainable code. Even worse is pessimization, when someone implements an "optimization" because they think it will be faster, but it ends up being slower, as well as being buggy, unmaintainable, etc. What is the most ridiculous example of...
I'm writing a simple IDictionary abstraction in C# that wraps a Dictionary<K, ICollection<V>>. Basically, it maps multiple values to one key. I can't decide whether to remove a key and its empty list when the last item in a values list is removed, or leave it (to avoid instantiating a new collection if the key is reused) and do checks ...
This one is a case of not doing your homework.:-) Apart from dynamic loading advantage, does it make sense to include a JavaScript library(jQuery in my case ) from a Google server when I can load it from my server as a single file comprised of the 19kb jQuery zip file + the additional JavaScript code I have written – all compressed wi...
Java was initially slow before the JIT but today performance is pretty close to C++. I want to know if someone has done measurable performance comparisons between the two languages? Where does Java fall short when compared to C++? Java provides many productivity gains to developers so they can write applications much quicker because o...
We are experiencing some slowdowns on our web-app deployed on a Tomcat 5.5.17 running on a Sun VM 1.5.0_06-b05 and our hosting company doesn't gives enough data to find the problem. We are considering installing lambda probe on the production server but it requires to enable jmx (com.sun.management.jmxremote) in order to obtain memory a...
I have two tables: a source table and a target table. The target table will have a subset of the columns of the source table. I need to update a single column in the target table by joining with the source table based on another column. The update statement is as follows: UPDATE target_table tt SET special_id = ( SELECT source_specia...