Core: added a warning about reusing connections.

Previously, reusing connections happened silently and was only
visible in monitoring systems.  This was shown to be not very user-friendly,
and administrators often didn't realize there were too few connections
available to withstand the load, and configured timeouts (keepalive_timeout
and http2_idle_timeout) were effectively reduced to keep things running.

To provide at least some information about this, a warning is now logged
(at most once per second, to avoid flooding the logs).
This commit is contained in:
Maxim Dounin 2020-08-10 18:52:59 +03:00
parent eae2b2fdf1
commit e240d88d44
2 changed files with 14 additions and 0 deletions

View File

@ -1298,6 +1298,19 @@ ngx_drain_connections(ngx_cycle_t *cycle)
ngx_queue_t *q;
ngx_connection_t *c;
if (cycle->reusable_connections_n == 0) {
return;
}
if (cycle->connections_reuse_time != ngx_time()) {
cycle->connections_reuse_time = ngx_time();
ngx_log_error(NGX_LOG_WARN, cycle->log, 0,
"%ui worker_connections are not enough, "
"reusing connections",
cycle->connection_n);
}
n = ngx_max(ngx_min(32, cycle->reusable_connections_n / 8), 1);
for (i = 0; i < n; i++) {

View File

@ -55,6 +55,7 @@ struct ngx_cycle_s {
ngx_queue_t reusable_connections_queue;
ngx_uint_t reusable_connections_n;
time_t connections_reuse_time;
ngx_array_t listening;
ngx_array_t paths;