10/03/2012

Apache Http Sever - a process based server


The architecture of Apache follows a multi-process
programming paradigm. When the Apache receives an HTTP connection request,
the request is first parsed by the main process of the Apache program. Then a separate
process will be assigned to prepare the requested HTML file. When the requested HTML
file includes only static contents, the file is then loaded from disks or caches. When the
file includes dynamic contents, such as the result of a database inquiry, Apache forwards
the request to one of its modular processes which was ignited when the Apache program
was started. The multi-process paradigm allows many processes to prepare HTML files
simultaneously, as many as several hundred. When too many processes are generated, the
system performance starts to degrade as the cost of context switching between processes
soars. It is, however, possible to configure and limit the maximum number of allowed
processes in Apache.

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