From: Vsevolod Stakhov <vsevolod@highsecure.ru>
Date: Thu, 18 Feb 2021 21:00:56 +0000 (+0000)
Subject: [Fix] Fix round-robin rotation
X-Git-Tag: 3.0~667
X-Git-Url: https://source.dussan.org/?a=commitdiff_plain;h=dbc9ff655dfb459eb8af328a82a5b8c848cda480;p=rspamd.git

[Fix] Fix round-robin rotation
---

diff --git a/src/libutil/upstream.c b/src/libutil/upstream.c
index 6acf420ea..612354043 100644
--- a/src/libutil/upstream.c
+++ b/src/libutil/upstream.c
@@ -1378,13 +1378,20 @@ rspamd_upstream_get_round_robin (struct upstream_list *ups,
 			}
 		}
 
-		if (up->checked * (up->errors + 1) < min_checked) {
+		/*
+		 * This code is used when all upstreams have zero weight
+		 * The logic is to select least currently used upstream and penalise
+		 * upstream with errors. The error penalty should no be too high
+		 * to avoid sudden traffic drop in this case.
+		 */
+		if (up->checked + up->errors * 2 < min_checked) {
 			min_checked_sel = up;
 			min_checked = up->checked;
 		}
 	}
 
 	if (max_weight == 0) {
+		/* All upstreams have zero weight */
 		if (min_checked > G_MAXUINT / 2) {
 			/* Reset all checked counters to avoid overflow */
 			for (i = 0; i < ups->alive->len; i ++) {