Re: Multiple .cgi scripts vs. one large script
Adam, How your server is going to load things depends entirely upon the server and its configuration. CGI is slow, ISAPI is faster, mod_perl and FastCGI are faster still. Which one you're using and how you use it will dramatically change things. On the other hand, if you only have a few thousand hits a day, it's probably not worth worrying about. As programmers get more experienced, the learn one of the most important rules of programming: do NOT worry about performance unless you have an extremely good reason to do so. Build your systems to be correct and complete and only after you have a known performance issue should you worry about that. Even then, profile the system to find out what the issue is. For example, if it's your database connection or complicated SQL queries which are causing the problem, fiddling with nested foreach loops probably isn't going to help that much. The don't worry about performance at first concept is one that many programmers balk at, but once you adopt it, it makes life much, much easier. Cheers, Ovid -- If this message is a response to a question on a mailing list, please send follow up questions to the list. Web Programming with Perl -- http://users.easystreet.com/ovid/cgi_course/ - Original Message From: Adam Waite [EMAIL PROTECTED] To: beginners-cgi@perl.org Sent: Thursday, June 15, 2006 4:43:56 AM Subject: Re: Multiple .cgi scripts vs. one large script Moore, George T. wrote: It depends on how you are using your scripts. The most expensive aspect of the files is the IO used to read them from the hard drive they reside on. If you are calling on the scripts multiple times and they have to be read each time, rather than being cached in memory, then you only want to read what is absolutely necessary. If one script always calls another then you are probably better having the subroutines, which would save IO. I'll be more specific about my setup. I have two scripts running a bulletin-board type thing. One of them is responsible for displaying all of the posts at once, or just displaying one at a time. The other script handles replying to posts or submitting new posts. I'd estimate that the script responsible for looking at the posts gets used more often, since more people look than actually say anything. It would be easier to maintain this program if I made these two functions subroutines of one larger script, and then called them using some switch logic. My main question then, is this. If a user visits the script, does the server only load one instance of the program per visit, or does each page change necessitate a new instance to begin? Because if only one process is loaded per visit (for instance, the program is compiled once and then used over and over while the user stays within pages covered by that program), it makes more sense to combine them into one larger program. However, if the whole program must be loaded by the server each time the user visits a new page (the program must be compiled and run for each request) then it makes sense to only load what is necessary by splitting up the script into several smaller ones. As may be obvious by now, I do not know very much about how servers handle requests for cgi programs, so I'm sorry if this question is posed in a nonsensical way. Thanks, Adam -- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] http://learn.perl.org/ http://learn.perl.org/first-response -- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] http://learn.perl.org/ http://learn.perl.org/first-response
Re: Multiple .cgi scripts vs. one large script
On Jun 14, 2006, at 6:40 PM, Hardly Armchair wrote: Hello All, I was wondering if it is more efficient (in terms of speed and processor load) to have two different scripts of approximately the same size called to handle two different functions, or to have one large script handle all cgi functions using subroutines. Or perhaps these situations are equivalent. I asked a similar question a few months back (How big is too big?). After learning a lot from the responses and where they led me I started looking more at CGI:: Application. The general theory I get from this framework (as it applies to your question) is that to help with management of subroutines you should create scripts (modules) that hold subroutines that perform similar tasks. No more than 10 subroutines in a script was the rule of thumb as I recall. Someone here mentioned that a Perl/CGI script that contains 1000 lines is probably about as big as you'd want one to get. The script I'm re-factoring to use CGI:: Application is now over 10,000 lines (with comments). It still performs pretty well, but never sees huge amounts of requests. I completely agree with Ovid's comment, do NOT worry about performance unless you have an extremely good reason to do so. That's one reason my script got so big. Performance still is not an issue for me, but management is becoming one. The One big one versus many small ones question seems best answered by personal preference, up to a point. For me, management was getting to be a pain. Now I'd strongly recommend CGI:: Application to anyone working on a perl/cgi app that will get bigger than that 1000 line max that was previously suggested or needs features easily provided by the framework and its plug-ins. Kindest Regards, -- Bill Stephenson 417-546-8390 -- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] http://learn.perl.org/ http://learn.perl.org/first-response
RE: Multiple .cgi scripts vs. one large script
It depends on how you are using your scripts. The most expensive aspect of the files is the IO used to read them from the hard drive they reside on. If you are calling on the scripts multiple times and they have to be read each time, rather than being cached in memory, then you only want to read what is absolutely necessary. If one script always calls another then you are probably better having the subroutines, which would save IO. -Original Message- From: Hardly Armchair [mailto:[EMAIL PROTECTED] Sent: Wednesday, June 14, 2006 4:40 PM To: beginners-cgi@perl.org Subject: Multiple .cgi scripts vs. one large script Hello All, I was wondering if it is more efficient (in terms of speed and processor load) to have two different scripts of approximately the same size called to handle two different functions, or to have one large script handle all cgi functions using subroutines. Or perhaps these situations are equivalent. I apologize if I have just asked an unanswerable question. Thanks, Adam -- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] http://learn.perl.org/ http://learn.perl.org/first-response -- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] http://learn.perl.org/ http://learn.perl.org/first-response
Re: Multiple .cgi scripts vs. one large script
Moore, George T. wrote: It depends on how you are using your scripts. The most expensive aspect of the files is the IO used to read them from the hard drive they reside on. If you are calling on the scripts multiple times and they have to be read each time, rather than being cached in memory, then you only want to read what is absolutely necessary. If one script always calls another then you are probably better having the subroutines, which would save IO. -Original Message- From: Hardly Armchair [mailto:[EMAIL PROTECTED] Sent: Wednesday, June 14, 2006 4:40 PM To: beginners-cgi@perl.org Subject: Multiple .cgi scripts vs. one large script Hello All, I was wondering if it is more efficient (in terms of speed and processor load) to have two different scripts of approximately the same size called to handle two different functions, or to have one large script handle all cgi functions using subroutines. Or perhaps these situations are equivalent. I apologize if I have just asked an unanswerable question. At least as important is maintainability. If you have several scripts, then you have to maintain several scripts. That may be fine, but it may not. If you do go down the road of using one script, look into CGI::Application or Catalyst on CPAN. Sean -- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] http://learn.perl.org/ http://learn.perl.org/first-response
Re: Multiple .cgi scripts vs. one large script
On Wed, 2006-14-06 at 16:40 -0700, Hardly Armchair wrote: Hello All, I was wondering if it is more efficient (in terms of speed and processor load) to have two different scripts of approximately the same size called to handle two different functions, or to have one large script handle all cgi functions using subroutines. Or perhaps these situations are equivalent. And what, exactly, do you mean by efficient? Most definitions of efficient mean getting the maximum benefit from available resources. So, does that mean the users have minimal response time? Or does it mean your code maintainers can fix bugs easily? Or does it mean your site has minimal cost on the internet? Normally, compartizing your site would mean you can deal with only one problem at a time, without worrying about its effects on the rest of the site. But you would have to decide exactly what efficient really means. -- __END__ Just my 0.0002 million dollars worth, --- Shawn For the things we have to learn before we can do them, we learn by doing them. Aristotle * Perl tutorials at http://perlmonks.org/?node=Tutorials * A searchable perldoc is at http://perldoc.perl.org/ -- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] http://learn.perl.org/ http://learn.perl.org/first-response
Re: Multiple .cgi scripts vs. one large script
Moore, George T. wrote: It depends on how you are using your scripts. The most expensive aspect of the files is the IO used to read them from the hard drive they reside on. If you are calling on the scripts multiple times and they have to be read each time, rather than being cached in memory, then you only want to read what is absolutely necessary. If one script always calls another then you are probably better having the subroutines, which would save IO. I'll be more specific about my setup. I have two scripts running a bulletin-board type thing. One of them is responsible for displaying all of the posts at once, or just displaying one at a time. The other script handles replying to posts or submitting new posts. I'd estimate that the script responsible for looking at the posts gets used more often, since more people look than actually say anything. It would be easier to maintain this program if I made these two functions subroutines of one larger script, and then called them using some switch logic. My main question then, is this. If a user visits the script, does the server only load one instance of the program per visit, or does each page change necessitate a new instance to begin? Because if only one process is loaded per visit (for instance, the program is compiled once and then used over and over while the user stays within pages covered by that program), it makes more sense to combine them into one larger program. However, if the whole program must be loaded by the server each time the user visits a new page (the program must be compiled and run for each request) then it makes sense to only load what is necessary by splitting up the script into several smaller ones. As may be obvious by now, I do not know very much about how servers handle requests for cgi programs, so I'm sorry if this question is posed in a nonsensical way. Thanks, Adam -- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] http://learn.perl.org/ http://learn.perl.org/first-response
