Unknown day of week – How to solve this Elasticsearch error

Opster Team

July-20, Version: 1.7-8.0

Before you begin reading this guide, we recommend you try running the Elasticsearch Check-Up which can resolve issues that cause many errors.

This guide will help you check for common problems that cause the log ” unknown day of week ” to appear. To understand the issues related to this log, read the explanation below about the following Elasticsearch concepts: plugin.

Advanced users might want to skip right to the common problems section in each concept or try running the Check-Up to analyze Elasticsearch configuration and help resolve this error.

Log Context

Log “unknown day of week [{}]”classname  is DayOfWeek.java We extracted the following from Elasticsearch source code for those seeking an in-depth context :

case "friday": return FRIDAY;
 case "7":
 case "sat":
 case "saturday": return SATURDAY;
 throw new ElasticsearchParseException("unknown day of week [{}]"; day);


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