Re: [RFC] remove documentation for client_*_buffer_size knobs

[Eric Wong <e@80x24.org>]

"Lin Jen-Shin (godfat)" <godfat@godfat.org> wrote:
> On Tue, Mar 17, 2015 at 5:15 AM, Eric Wong <e@80x24.org> wrote:
> [...]
> > In the future, we may remove these options entirely.  For now,
> > having too much documentation and tuning options may confuse new
> > users and minimize the importance/visibility of other options,
> > so remove documentation for this.
> >
> > I'm not convinced user-space buffer size tuning has a place in
> > an application server written in a high-level language.  Heck,
> > many servers written in C do not have this.
> 
> Personally I do like various options even if I won't touch them,
> since maybe I'll on some day. We could put more advanced
> options in advanced configuration page to avoid confusion.
> Or a warning like "Don't touch them unless you really know
> what you're doing" should be good (scary) enough.

Probably a warning is enough.  Patch below for client_body_buffer_size

> However, I don't know if it makes sense to configure
> client_header_buffer_size and client_max_body_size.

I think you meant client_body_buffer_size (not max_body), which is one
I'm least enthusiastic about tuning.

client_max_body_size needs to stay, major DoS potential there.

> (nginx has them, I think?) If not, I guess it's really fine to
> remove them, and we're free to change them or stop
> providing those options in the future. That's also good, I guess.

nginx documentation is a forest nowadays and I'm trying to avoid
going down that path.

I've also been thinking about auto-tuning/variable header buffer sizes.
Some apps rely on giant URLs and cookies while others do not.  But maybe
the apps with giant URLs/cookies are screwed anyways performance-wise
and yahns shouldn't try too hard to optimize for them.

-------------------------------8<---------------------------
Subject: [PATCH] doc: note possible removal of client_body_buffer_size

This is probably the least useful tuning knob and may be removed
in the future; so at least warn users about it.

ref: <CAA2_N1t_UJZO9Vu9vx3NxysCx+okip8_pM+NpwhHrExM+f1e+Q@mail.gmail.com>
---
 Documentation/yahns_config.txt | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/Documentation/yahns_config.txt b/Documentation/yahns_config.txt
index d18263d..3683298 100644
--- a/Documentation/yahns_config.txt
+++ b/Documentation/yahns_config.txt
@@ -208,6 +208,9 @@ Ruby it is running under.
     if input_buffering is false.  This also governs the size of an
     individual read(2) system call when reading a request body.
 
+    There is generally no need to change this value and this directive
+    may be removed in the future.
+
     Default: 8192 bytes (8 kilobytes)
 
 * client_header_buffer_size INTEGER
-- 
EW