After installing telegraf 1.9 on 23.11 in the morning, memory consumption had increased significantly. It increased immediately after the upgrade and had started degrading severely ~24h after the installation. This was observed on several servers, few times OOM killer kicked in. Rolled back to 1.8.3.
CentOS Linux release 7.5.1804 (Core)
Linux 3.10.0-862.14.4.el7.x86_64 #1 SMP Wed Sep 26 15:12:11 UTC 2018 x86_64 x86_64 x86_64 GNU/Linux