comparison src/http/ngx_http_cache.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 d10bcb07d9d4
children d620f497c50f
comparison
equal deleted inserted replaced
4384:a8b6d5dee539 4385:70ba81827472
77 ngx_buf_t *buf; 77 ngx_buf_t *buf;
78 78
79 ngx_http_file_cache_t *file_cache; 79 ngx_http_file_cache_t *file_cache;
80 ngx_http_file_cache_node_t *node; 80 ngx_http_file_cache_node_t *node;
81 81
82 ngx_msec_t lock_timeout;
83 ngx_msec_t wait_time;
84
85 ngx_event_t wait_event;
86
87 unsigned lock:1;
88 unsigned waiting:1;
89
82 unsigned updated:1; 90 unsigned updated:1;
83 unsigned updating:1; 91 unsigned updating:1;
84 unsigned exists:1; 92 unsigned exists:1;
85 unsigned temp_file:1; 93 unsigned temp_file:1;
86 }; 94 };