Briefly, this error occurs when the date format provided in the Elasticsearch query is incorrect or invalid. The system expects a string or number value for the month day field, but it received something else. To resolve this issue, you can check the date format in your query and ensure it matches the expected format. Also, verify that the field you’re querying is indeed a date field. Lastly, ensure that the date values you’re using are valid and within the acceptable range.
This guide will help you check for common problems that cause the log ” invalid month day value for [{}] field. expected string/number value or an ” to appear. To understand the issues related to this log, read the explanation below about the following Elasticsearch concepts: plugin.
Log Context
Log “invalid month day value for [{}] field. expected string/number value or an” class name is MonthTimes.java. We extracted the following from Elasticsearch source code for those seeking an in-depth context :
} else if (token == XContentParser.Token.START_ARRAY) {
while ((token = parser.nextToken()) != XContentParser.Token.END_ARRAY) {
daysSet.add(parseDayValue(parser; token));
}
} else {
throw new ElasticsearchParseException("invalid month day value for [{}] field. expected string/number value or an " +
"array of string/number values; but found [{}]"; currentFieldName; token);
}
} else if (TIME_FIELD.match(currentFieldName; parser.getDeprecationHandler())) {
if (token != XContentParser.Token.START_ARRAY) {
try {
