Mercurial > hg > nginx
comparison src/core/ngx_resolver.h @ 6366:2e5c027f2a98
Resolver: per-request DNS server balancer.
Previously, a global server balancer was used to assign the next DNS server to
send a query to. That could lead to a non-uniform distribution of servers per
request. A request could be assigned to the same dead server several times in a
row and wait longer for a valid server or even time out without being processed.
Now each query is sent to all servers sequentially in a circle until a
response is received or timeout expires. Initial server for each request is
still globally balanced.
| author | Roman Arutyunyan <arut@nginx.com> |
|---|---|
| date | Thu, 28 Jan 2016 15:28:20 +0300 |
| parents | d35b4d590b2d |
| children | 5a16d40c63de |
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| 6365:d35b4d590b2d | 6366:2e5c027f2a98 |
|---|---|
| 91 | 91 |
| 92 time_t expire; | 92 time_t expire; |
| 93 time_t valid; | 93 time_t valid; |
| 94 uint32_t ttl; | 94 uint32_t ttl; |
| 95 | 95 |
| 96 ngx_uint_t last_connection; | |
| 97 | |
| 96 ngx_resolver_ctx_t *waiting; | 98 ngx_resolver_ctx_t *waiting; |
| 97 } ngx_resolver_node_t; | 99 } ngx_resolver_node_t; |
| 98 | 100 |
| 99 | 101 |
| 100 typedef struct { | 102 typedef struct { |