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.SSI doesn't bring anything new to the table in thatregard.In general, SSI programs tend to be less of a drain on the serverthan full-fledged CGI.SSI programs are usually small and simple-theyonly have to produce text, after all-and seldom do much of anysignificance with files.Page-hit counters that rely on generatinginline graphics put far more stress on a server than an SSI counterdoes.Still, a dozen-or a hundred-instances of your SSI program runningat once could steal memory and processor slices needed by theserver to satisfy client requests.Imagine that you are Webmasterof a large site.On each of the 250 pages for which you're responsible,you include not one but all the SSI examples in this chapter.Each page hit would produce seven separate processes, each ofwhich has to jostle with the others in resource contention.Ina worst-case scenario, with 100 pages being hit a minute, youwould have 700 scripts running each minute, 10 or more simultaneouslyat all times.This kind of load would seriously affect your server'scapability to do anything else-like serve up pages to those userswho stop by to see your wonderful SSI handiwork.You don't find much difference among platforms either.Some SSIutilities run more efficiently in UNIX, others work better underWindows NT, and in the end, everything balances out.Programsthat use the NT registry have a distinct advantage over programsthat hit the file system to save data.The registry functionslike a back-end database-always open, always ready for queriesand updates.The code for handling concurrency is already loadedand running as part of the operating system, so your program canbe smaller and tighter.On the other hand, pipes and forks tendto run more efficiently under some flavors of UNIX, so if yourprogram does that sort of thing, you are better off in that environment.In short, don't pick your server operating system based on whatSSI programs you plan to run.If you run into performance problems,adding RAM will usually give your server the extra head room itneeds to handle the load imposed by SSI [ Pobierz całość w formacie PDF ]
