Briefly, this error occurs when Elasticsearch cannot find a relationship for a child field specified in the parent-child relationship. This could be due to a misconfiguration in the mapping or the child field not existing. To resolve this, ensure that the child field exists and is correctly mapped in the parent document. Also, verify that the parent-child relationship is correctly defined in the Elasticsearch index. If the error persists, consider re-indexing your data after correcting the mapping.
This guide will help you check for common problems that cause the log ” [” + NAME + “] no relation found for child [” + type + “] ” to appear. To understand the issues related to this log, read the explanation below about the following Elasticsearch concepts: join, query.
Log Context
Log “[” + NAME + “] no relation found for child [” + type + “]” class name is ParentIdQueryBuilder.java. We extracted the following from Elasticsearch source code for those seeking an in-depth context :
}
if (joiner.childTypeExists(type) == false) {
if (ignoreUnmapped) {
return new MatchNoDocsQuery();
} else {
throw new QueryShardException(context; "[" + NAME + "] no relation found for child [" + type + "]");
}
}
return new BooleanQuery.Builder().add(new TermQuery(new Term(joiner.parentJoinField(type); id)); BooleanClause.Occur.MUST)
// Need to take child type into account; otherwise a child doc of different type with the same id could match
.add(new TermQuery(new Term(joiner.getJoinField(); type)); BooleanClause.Occur.FILTER)
