id	summary	reporter	owner	description	type	status	priority	milestone	component	version	resolution	keywords	cc	uname	nginx_version
2598	ngx_http_limit_req_module documentation should specify rate_limit work on millisecond basis	alexgarel@…		"While trying to use rate limiting on NGINX, I was a bit lost because I specified I wanted a 6000r/m rate limit, but a client doing 154 request would have been rejected (I was in dry mode, so no harm).

I did setup burst=100 because, I though burst was some more extra on the 6000 request.

I found the solution thanks to a stack overflow post (stackoverflow.com/a/70989063/2886726) citing the [https://www.nginx.com/blog/rate-limiting-nginx/ nginx blog post]

> In the example, the rate cannot exceed 10 requests per second. NGINX actually tracks requests at millisecond granularity, so this limit corresponds to 1 request every 100 milliseconds (ms). Because we are not allowing for bursts (see the next section), this means that a request is rejected if it arrives less than 100ms after the previous permitted one.

This information about millisecond granularity and the fact that rate limiting is directly transformed in a temporality at a single request level is essential and should be part of the reference documentation.

In my case, I can in fact set burst=6000 to only limit at minute granularity.

It is important because, other rate limiting implementation [https://redis.com/glossary/rate-limiting/ may use other techniques, like leaky buckets] which does not lead to same type of configuration."	defect	closed	minor		documentation	1.25.x	duplicate			Linux off2 5.15.74-1-pve #1 SMP PVE 5.15.74-1 (Mon, 14 Nov 2022 20:17:15 +0100) x86_64 GNU/Linux	"nginx version: nginx/1.18.0
built with OpenSSL 1.1.1n  15 Mar 2022 (running with OpenSSL 1.1.1w  11 Sep 2023)
TLS SNI support enabled
configure arguments: --with-cc-opt='-g -O2 -ffile-prefix-map=/build/nginx-x3gsRV/nginx-1.18.0=. -fst
ack-protector-strong -Wformat -Werror=format-security -fPIC -Wdate-time -D_FORTIFY_SOURCE=2' --with-
ld-opt='-Wl,-z,relro -Wl,-z,now -fPIC' --prefix=/usr/share/nginx --conf-path=/etc/nginx/nginx.conf -
-http-log-path=/var/log/nginx/access.log --error-log-path=/var/log/nginx/error.log --lock-path=/var/
lock/nginx.lock --pid-path=/run/nginx.pid --modules-path=/usr/lib/nginx/modules --http-client-body-t
emp-path=/var/lib/nginx/body --http-fastcgi-temp-path=/var/lib/nginx/fastcgi --http-proxy-temp-path=
/var/lib/nginx/proxy --http-scgi-temp-path=/var/lib/nginx/scgi --http-uwsgi-temp-path=/var/lib/nginx
/uwsgi --with-compat --with-debug --with-pcre-jit --with-http_ssl_module --with-http_stub_status_mod
ule --with-http_realip_module --with-http_auth_request_module --with-http_v2_module --with-http_dav_
module --with-http_slice_module --with-threads --with-http_addition_module --with-http_gunzip_module
 --with-http_gzip_static_module --with-http_sub_module
"