String s = ""; for(i=0;i<....){ s = some Assignment; } or for(i=0;i<..){ String s = some Assignment; } I don't need to use 's' outside the loop ever again. The first option is perhaps better since a new String is not initialized each time. The second however would result in the scope of the variable being limited to the loo...
What would be the most optimal algorithm (performance-wise) to calculate the number of divisors of a given number? It'll be great if you could provide pseudocode or a link to some example. EDIT: All the answers have been very helpful, thank you. I'm implementing the Sieve of Atkin and then I'm going to use something similar to what Jon...
CPU Cycles, Memory Usage, Execution Time, etc.? Added: Is there a quantitative way of testing performance in JavaScript besides just perception of how fast the code runs? ...
I don't expect a straightforward silver bullet answer to this, but what are the best practices for ensuring good performance for SharePoint 2007 sites? We've a few sites for our intranet, and it generally is thought to run slow. There's plenty of memory and processor power in the servers, but the pages just don't 'snap' like you'd expec...
I'm building a PHP site, but for now the only PHP I'm using is a half-dozen or so includes on certain pages. (I will probably use some database queries eventually.) Are simple include() statements a concern for speed or scaling, as opposed to static HTML? What kinds of things tend to cause a site to bog down? ...
Is there a runtime performance penalty when using interfaces (abstract base classes) in C++? ...
It's my understanding that nulls are not indexable in DB2, so assuming we have a huge table (Sales) with a date column (sold_on) which is normally a date, but is occasionally (10% of the time) null. Furthermore, let's assume that it's a legacy application that we can't change, so those nulls are staying there and mean something (let's s...
The situation: we have a large database with a number of denormalized tables. We frequently have to resummarize the data to keep the summary tables in synch. We've talked on and off about using computed columns to keep the data fresh. We've also talked about triggers, but that's a separate discussion. In our summary tables, we denormali...
We log values and we only log them once in a table. When we add values to the table we have to do a look up everytime to see if it needs to insert the value or just grab the id. We have an index on the table (not on the primary key) but there are about 350,000 rows (so it is taking 10 seconds to do 10 of these values). So either W...
I'm a total newbie, but I was writing a little program that worked on strings in C# and I noticed that if I did a few things differently, the code executed significantly faster. So it had me wondering, how do you go about clocking your code's execution speed? Are there any (free)utilities? Do you go about it the old-fashioned way with a...
I've actually solved this, but I'm posting it for posterity. I ran into a very odd issue with the DataGridView on my dual-monitor system. The issue manifests itself as an EXTREMELY slow repaint of the control (like 30 seconds for a full repaint), but only when it is on one of my screens. When on the other, the repaint speed is fine. I h...
Although I do understand the serious implications of playing with this function (or at least that's what I think), I fail to see why it's becoming one of these things that respectable programmers wouldn't ever use, even those who don't even know what it is for. Let's say I'm developing an application where memory usage varies extremely ...
What are the preffered plugins for monitoring and analyzing the performance of a Rails app? I'm looking for both database/query analyzers and the rest of the stack if possible, though not necessarily all in one plugin. Which ones do you recommend? ( Bonus points for free ones :) For example, this one looks spify. ...
This is my setting: I have written a .NET application for local client machines, which implements a feature that could also be used on a webpage. To keep this example simple, assume that the client installs a software into which he can enter some data and gets some data back. The idea is to create a webpage that holds a form into which...
I have an SP that takes 10 seconds to run about 10 times (about a second every time it is ran). The platform is asp .net, and the server is SQL Server 2005. I have indexed the table (not on the PK also), and that is not the issue. Some caveats: usp_SaveKeyword is not the issue. I commented out that entire SP and it made not difference...
What is the best (cleanest, most efficient) way to write saturating addition in C? The function or macro should add two unsigned inputs (need both 16- and 32-bit versions) and return all-bits-one (0xFFFF or 0xFFFFFFFF) if the sum overflows. Target is x86 and ARM using gcc (4.1.2) and Visual Studio (for simulation only, so a fallback im...
Is there a difference in performance (in oracle) between Select * from Table1 T1 Inner Join Table2 T2 On T1.ID = T2.ID And Select * from Table1 T1, Table2 T2 Where T1.ID = T2.ID ? ...
Server virtualization is a big thing these days, so I'm tasked at work to install some of our software on a virtualized server and see what happens. Long story short: a rsync transfer promptly brings the virtualized server to its knees. The virtualization host is a beefy machine with no other load; I don't think this should be happening....
I am running my junit tests via ant and they are running substantially slower than via the IDE. My ant call is: <junit fork="yes" forkmode="once" printsummary="off"> <classpath refid="test.classpath"/> <formatter type="brief" usefile="false"/> <batchtest todir="${test.results.dir}/xml"> <formatter...
Hi, we're have a client that needs to get interactive messages from a server, from clients that are distributed around the world behind all kinds of firewalls with all kinds of ports closed. The only thing we can rely on is HTTP port 80 (and HTTPS 443). The design is basically modeled after XMPP (the Jabber protocol), using our client a...