performance

MyISAM versus InnoDB

I'm working on a projects which involves a lot of database writes, I'd say (70% inserts and 30% reads). This ratio would also include updates which I consider to be one read and one write. The reads can be dirty (e.g. I don't need 100% accurate information at the time of read). The task in question will be doing over 1 million database...

One database or many?

I am developing a website that will manage data for multiple entities. No data is shared between entities, but they may be owned by the same customer. A customer may want to manage all their entities from a single "dashboard". So should I have one database for everything, or keep the data seperated into individual databases? Is there ...

JavaScript Profiler in IE

Does anyone know a tool for Profiling JavaScript in IE? List available: IE8 (Internet Explorer 8 only) JavaScript Profiler YUI! ...

When to use STL bitsets instead of separate variables?

In what situation would it be more appropriate for me to use a bitset (STL container) to manage a set of flags rather than having them declared as a number of separate (bool) variables? Will I get a significant performance gain if I used a bitset for 50 flags rather than using 50 separate bool variables? ...

PHP sleep() silently hogs CPU

I'm running Apache on Linux within VMWare. One of the PHP pages I'm requesting does a sleep(), and I find that if I attempt to request a second page whilst the first page is sleep()'ing, the second page hangs, waiting for the sleep() from the first page to finish. Has anyone else seen this behaviour? I know that PHP isn't multi-threaded...

What strategies have you employed to improve web application performance?

Any personal experience in overcoming web application performance hurdles? Any recommended strategies for improving the performance of a data-driven web application? My development team works on a web application (JSP reports, HTML, JavaScript) that uses an Oracle database (PL/SQL). The key functionality the application delivers is ...

Do you have any tips to improve ReSharper and/or Visual Studio performance ?

I'm using visual studio 2008 and ReSharper 4 and it's kind of slow. My machine has 2 GB of RAM, dual core processor and a 7200 rpm hard disk. I know more RAM and a faster hard disk could improve performance, but do you have any tips to improve ReSharper/Visual Studio performance? ...

What to do about ScanAlert?

One of my clients uses McAfee ScanAlert (i.e., HackerSafe). It basically hits the site with about 1500 bad requests a day looking for security holes. Since it demonstrates malicious behavior it is tempting to just block it after a couple bad requests, but maybe I should let it exercise the UI. Is it a true test if I don't let it finish...

Is there some way to speed up recursion by remembering child nodes?

For example, Look at the code that calculates the n-th Fibonacci number: fib(int n) { if(n==0 || n==1) return 1; return fib(n-1) + fib(n-2); } The problem with this code is that it will generate stack overflow error for any number greater than 15 (in most computers). Assume that we are calculating fib(10). In this pro...

Is there a performance difference between i++ and ++i in C?

Is there a performance difference between i++ and ++i if the resulting value is not used? ...

How costly is Reflection? Really.

I constantly hear how bad reflection is to use. While I generally avoid reflection and rarely find situations where it is impossible to solve my problem without it, I was wondering... For those who have used reflection in applications, have you measured performance hits and, is it really so bad? ...

Ruby Performance

I'm pretty keen to develop my first Ruby app, as my company has finally blessed its use internally. In everything I've read about Ruby up to v1.8, there is never anything positive said about performance, but I've found nothing about version 1.9. The last figures I saw about 1.8 had it drastically slower than just about everything out th...

How is data compression more effective than indexing for search performance?

For our application, we keep large amounts of data indexed by three integer columns (source, type and time). Loading significant chunks of that data can take some time and we have implemented various measures to reduce the amount of data that has to be searched and loaded for larger queries, such as storing larger granularities for queri...

Any negative impacts when using Mod-Rewrite?

I know there are a lot of positive things mod-rewrite accomplishes. But are there any negative? Obviously if you have poorly written rules your going to have problems. But what if you have a high volume site and your constantly using mod-rewrite, is it going to have a significant impact on performance? I did a quick search for some benc...

What's your favorite profiling tool (for C++)

So far, I've only used Rational Quantify. I've heard great things about Intel's VTune, but have never tried it! Edit: I'm mostly looking for software that will instrument the code, as I guess that's about the only way to get very fine results. See also: What are some good profilers for native C++ on Windows? ...

Perfmon File Analysis Tools

I have a bunch of perfmon files that have captured information over a period of time. Whats the best tool to crunch this information? Idealy I'd like to be able to see avg stats per hour for the object counters that have been monitored. ...

When do you use table clusters?

How do you determine when to use table clusters? There are two types, index and hash, to use for different cases. In your experience, have the introduction and use of table clusters paid off? If none of your tables are set up this way, modifying them to use table clusters would add to the complexity of the set up. But would the expected...

Multiple classes in a header file vs. a single header file per class

For whatever reason, our company has a coding guideline that states: Each class shall have it's own header and implementation file. So if we wrote a class called MyString we would need an associated MyStringh.h & MyString.cxx. Does anyone else do this? Has anyone seen any compiling performance repercussions as a result? Does 5000 cl...

SQL Server 2k5 memory consumption?

I have a development vm which is running sql server as well as some other apps for my stack, and I found that the other apps are performing awfully. After doing some digging, SQL Server was hogging the memory. After a quick web search I discovered that by default, it will consume as much memory as it can in order to cache data and give...

Is DateTime.Now the best way to measure a function's performance?

I need to find a bottleneck and need to accurately as possible measure time. Is the following Code Snippet the best way to measure the performance? DateTime startTime = DateTime.Now; // Some Execution Process DateTime endTime = DateTime.Now; TimeSpan totalTimeTaken = endTime.Subtract(startTime); ...