Lingering close for connections with pipelined requests. This is expected to help with clients using pipelining with some constant depth, such as apt[1][2]. When downloading many resources, apt uses pipelining with some constant depth, a number of requests in flight. This essentially means that after receiving a response it sends an additional request to the server, and this can result in requests arriving to the server at any time. Further, additional requests are sent one-by-one, and can be easily seen as such (neither as pipelined, nor followed by pipelined requests). The only safe approach to close such connections (for example, when keepalive_requests is reached) is with lingering. To do so, now nginx monitors if pipelining was used on the connection, and if it was, closes the connection with lingering. [1] https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=973861#10 [2] https://mailman.nginx.org/pipermail/nginx-devel/2023-January/ZA2SP5SJU55LHEBCJMFDB2AZVELRLTHI.html

/*
 * Copyright (C) Igor Sysoev
 * Copyright (C) Nginx, Inc.
 */


#ifndef _NGINX_H_INCLUDED_
#define _NGINX_H_INCLUDED_


#define nginx_version      1023004
#define NGINX_VERSION      "1.23.4"
#define NGINX_VER          "nginx/" NGINX_VERSION

#ifdef NGX_BUILD
#define NGINX_VER_BUILD    NGINX_VER " (" NGX_BUILD ")"
#else
#define NGINX_VER_BUILD    NGINX_VER
#endif

#define NGINX_VAR          "NGINX"
#define NGX_OLDPID_EXT     ".oldbin"


#endif /* _NGINX_H_INCLUDED_ */