From e240d88d4497afd2493358e938f74486750bc776 Mon Sep 17 00:00:00 2001 From: Maxim Dounin Date: Mon, 10 Aug 2020 18:52:59 +0300 Subject: [PATCH] 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). --- src/core/ngx_connection.c | 13 +++++++++++++ src/core/ngx_cycle.h | 1 + 2 files changed, 14 insertions(+) diff --git a/src/core/ngx_connection.c b/src/core/ngx_connection.c index 88fefcea2..91e1b3b2e 100644 --- a/src/core/ngx_connection.c +++ b/src/core/ngx_connection.c @@ -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++) { diff --git a/src/core/ngx_cycle.h b/src/core/ngx_cycle.h index 54fa2e6bf..0f7d9bc74 100644 --- a/src/core/ngx_cycle.h +++ b/src/core/ngx_cycle.h @@ -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;