Github user Yuanuo commented on the issue:
https://github.com/apache/tomcat/pull/126
Ok. It has been closed, but I still want to express my views here.
I am very sorry about my English level. These texts are all done with
Google Translate.
1. In any actual environment, the resources and bandwidth of the server are
limited, so the speed limit function is necessary.
2, Nginx, Apache, Lighttpd Web servers have Sendfile module to achieve
high-performance data transmission. I am using Nginx now, the other two have
not been studied. Nginx's Sendfile mode also supports speed limit, which is
implemented using the "X-Accel-Limit-Rate" header. And the implementation
principle of the speed limit is basically the same, in short, it is guaranteed
to transmit only the bytes of certain data within one second, so the
process/thread sleep wait will be generated. But does this speed limit feature
make Nginx a low-performance web server? The answer is no, this feature will
only work when you use it, but it is turned off by default. But this also
provides a possibility for people to use.
3, we all know that Tomcat is not only used to transfer a few css or js,
and according to the Tomcat implementation, to enable the Sendfile mode, the
default sendfileSize is also 48KB, that is, only data larger than this amount
will try to enable Sendfile transfer mode. In other applications, such as to do
a file download server, you can't make any restrictions so that several
download connections will run out of server bandwidth.
4, in the modern Web environment, generally do not directly use Tomcat as a
Web server, but use Nginx+Tomcat or other working modes. If you are dealing
with static resources, css, js, jpg, png, etc., most of them can be handed over
to Nginx for direct processing without going through Tomcat. In this case,
Tomcat's Sendfile will never be used. What does this mean? That is to say, the
Sendfile function that everyone has to maintain will not be used, even if a lot
of code is written to implement APR, NIO, NIO2 and other modes.
5, the code I submitted does not destroy the original working mode, which
is what it is, these codes will not play any role by default. It will only be
turned on after some parameters have been set. This gives people a possibility,
but it is decided by people. On the contrary, even if there is a default
high-performance NIO implementation of Sendfile, but people are worried that
their server bandwidth is used up, and can not carry out any speed limit, then
the default implementation of the Sendfile function will never be used, then
everyone writes these What is the use of the code? Yes, you said that these
requirements can be achieved by writing a Servlet or Filter yourself, yes,
that's it. But everyone who uses Tomcat has to write a set of Servlets or
Filters to implement this function. Who is the implementation of Tomcat's own
implementation? I think this speed limit feature for Sendfile does not break
any existing code and structure, but rather an enhancement to Tomcat.
6. Yes, there is no example of how to use it here. However, in the
submitted code, the DefaultServlet has only been modified a few lines, and
these lines (lines 2068-2070) are examples of how to use them. So some people
may not have viewed the submitted code at all, and directly rely on other
people's opinions to negate my code submission, showing that this is
unacceptable, and I also doubt this kind of work attitude. Sorry! Since this
has been closed, I am not going to describe the usage here.
Finally, no matter what, I decided to use Nginx's Sendfile to achieve my
needs. This is how I use it in my current PHP code. This submission will be
abandoned.
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