October 1998
Intermediate to advanced
374 pages
12h 6m
English
Content preview from Web Performance TuningBecome an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
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General CGI Tips
No matter how optimized your hardware and operating system are, it is easy to get truly awful performance with a badly written CGI. There is no constraint on how long a CGI is allowed to run, so if your CGI is ill-mannered or overloaded, the user will suffer. We should distinguish here between merely inefficient CGIs, infinite loops, and runaways. Coding for efficiency is a huge topic and is highly language-dependent. We will cover efficiency in the section “CGI Language—Specific Optimization Tips,” later in this chapter.
Infinite Loops
If your CGI somehow gets into an infinite loop, the web server may well wait forever for the CGI to return results. This, in turn, means that the user will probably be left staring at a blank or partially filled browser for quite some time. Or worse, they’ll just hit the Back button and then try again, putting another infinitely long CGI in motion on your server, and thus using up CPU time that produces nothing.
CGI programs don’t know if and when the user hits the Stop button on the browser. The program often finds out only when it tries to output HTML and receives a SIGPIPE signal because the socket is no longer valid, but this may depend on the configuration of the operating system and web server.
How to find and kill infinitely looping CGIs
To kill an infinitely looping CGI, you must
first find its process ID (PID). The classic way to do this is with
the Unix ps command. Under Solaris, for example, you can list all of your processes ...
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O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.Julian F.
I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.Amir M.
I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.