Mercurial > hg > nginx
view src/http/ngx_http_busy_lock.h @ 4385:70ba81827472
Cache locks initial implementation.
New directives: proxy_cache_lock on/off, proxy_cache_lock_timeout. With
proxy_cache_lock set to on, only one request will be allowed to go to
upstream for a particular cache item. Others will wait for a response
to appear in cache (or cache lock released) up to proxy_cache_lock_timeout.
Waiting requests will recheck if they have cached response ready (or are
allowed to run) every 500ms.
Note: we intentionally don't intercept NGX_DECLINED possibly returned by
ngx_http_file_cache_read(). This needs more work (possibly safe, but needs
further investigation). Anyway, it's exceptional situation.
Note: probably there should be a way to disable caching of responses
if there is already one request fetching resource to cache (without waiting
at all). Two possible ways include another cache lock option ("no_cache")
or using proxy_no_cache with some supplied variable.
Note: probably there should be a way to lock updating requests as well. For
now "proxy_cache_use_stale updating" is available.
author | Maxim Dounin <mdounin@mdounin.ru> |
---|---|
date | Mon, 26 Dec 2011 11:15:23 +0000 |
parents | 4c43e25d11ea |
children | d620f497c50f |
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/* * Copyright (C) Igor Sysoev */ #ifndef _NGX_HTTP_BUSY_LOCK_H_INCLUDED_ #define _NGX_HTTP_BUSY_LOCK_H_INCLUDED_ #include <ngx_config.h> #include <ngx_core.h> #include <ngx_event.h> #include <ngx_http.h> typedef struct { u_char *md5_mask; char *md5; int cacheable; int busy; int max_busy; int waiting; int max_waiting; time_t timeout; ngx_event_mutex_t *mutex; } ngx_http_busy_lock_t; typedef struct { time_t time; ngx_event_t *event; void (*event_handler)(ngx_event_t *ev); u_char *md5; int slot; } ngx_http_busy_lock_ctx_t; int ngx_http_busy_lock(ngx_http_busy_lock_t *bl, ngx_http_busy_lock_ctx_t *bc); int ngx_http_busy_lock_cacheable(ngx_http_busy_lock_t *bl, ngx_http_busy_lock_ctx_t *bc, int lock); void ngx_http_busy_unlock(ngx_http_busy_lock_t *bl, ngx_http_busy_lock_ctx_t *bc); char *ngx_http_set_busy_lock_slot(ngx_conf_t *cf, ngx_command_t *cmd, void *conf); #endif /* _NGX_HTTP_BUSY_LOCK_H_INCLUDED_ */