Mercurial > hg > nginx-quic
view src/event/ngx_event_pipe.h @ 4207:4fc91bae6f83
Better recheck of dead upstream servers.
Previously nginx used to mark backend again as live as soon as fail_timeout
passes (10s by default) since last failure. On the other hand, detecting
dead backend takes up to 60s (proxy_connect_timeout) in typical situation
"backend is down and doesn't respond to any packets". This resulted in
suboptimal behaviour in the above situation (up to 23% of requests were
directed to dead backend with default settings).
More detailed description of the problem may be found here (in Russian):
http://mailman.nginx.org/pipermail/nginx-ru/2011-August/042172.html
Fix is to only allow one request after fail_timeout passes, and
mark backend as "live" only if this request succeeds.
Note that with new code backend will not be marked "live" unless "check"
request is completed, and this may take a while in some specific workloads
(e.g. streaming). This is believed to be acceptable.
author | Maxim Dounin <mdounin@mdounin.ru> |
---|---|
date | Wed, 12 Oct 2011 14:22:48 +0000 |
parents | b66712cde67d |
children | aae172db7ac8 |
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/* * Copyright (C) Igor Sysoev */ #ifndef _NGX_EVENT_PIPE_H_INCLUDED_ #define _NGX_EVENT_PIPE_H_INCLUDED_ #include <ngx_config.h> #include <ngx_core.h> #include <ngx_event.h> typedef struct ngx_event_pipe_s ngx_event_pipe_t; typedef ngx_int_t (*ngx_event_pipe_input_filter_pt)(ngx_event_pipe_t *p, ngx_buf_t *buf); typedef ngx_int_t (*ngx_event_pipe_output_filter_pt)(void *data, ngx_chain_t *chain); struct ngx_event_pipe_s { ngx_connection_t *upstream; ngx_connection_t *downstream; ngx_chain_t *free_raw_bufs; ngx_chain_t *in; ngx_chain_t **last_in; ngx_chain_t *out; ngx_chain_t **last_out; ngx_chain_t *free; ngx_chain_t *busy; /* * the input filter i.e. that moves HTTP/1.1 chunks * from the raw bufs to an incoming chain */ ngx_event_pipe_input_filter_pt input_filter; void *input_ctx; ngx_event_pipe_output_filter_pt output_filter; void *output_ctx; unsigned read:1; unsigned cacheable:1; unsigned single_buf:1; unsigned free_bufs:1; unsigned upstream_done:1; unsigned upstream_error:1; unsigned upstream_eof:1; unsigned upstream_blocked:1; unsigned downstream_done:1; unsigned downstream_error:1; unsigned cyclic_temp_file:1; ngx_int_t allocated; ngx_bufs_t bufs; ngx_buf_tag_t tag; ssize_t busy_size; off_t read_length; off_t length; off_t max_temp_file_size; ssize_t temp_file_write_size; ngx_msec_t read_timeout; ngx_msec_t send_timeout; ssize_t send_lowat; ngx_pool_t *pool; ngx_log_t *log; ngx_chain_t *preread_bufs; size_t preread_size; ngx_buf_t *buf_to_file; ngx_temp_file_t *temp_file; /* STUB */ int num; }; ngx_int_t ngx_event_pipe(ngx_event_pipe_t *p, ngx_int_t do_write); ngx_int_t ngx_event_pipe_copy_input_filter(ngx_event_pipe_t *p, ngx_buf_t *buf); ngx_int_t ngx_event_pipe_add_free_buf(ngx_event_pipe_t *p, ngx_buf_t *b); #endif /* _NGX_EVENT_PIPE_H_INCLUDED_ */