Briefly, this error occurs when Elasticsearch encounters unexpected issues during the mapping process. This could be due to incorrect data types, incorrect field names, or other inconsistencies in the data being indexed. To resolve this issue, you can check the data being indexed for inconsistencies, ensure that the mapping is correctly defined for the data, or use the Elasticsearch error logs to identify the specific issue causing the error.
This guide will help you check for common problems that cause the log ” expected mapper parsing failures. got ” to appear. To understand the issues related to this log, read the explanation below about the following Elasticsearch concepts: replication.
Overview
Replication refers to storing a redundant copy of the data. Starting from version 7.x, Elasticsearch creates one primary shard with a replication factor set to 1. Replicas never get assigned to the same node on which primary shards are assigned, which means you should have at least two nodes in the cluster to assign the replicas. If a primary shard goes down, the replica automatically acts as a primary shard.
What it is used for
Replicas are used to provide high availability and failover. A higher number of replicas is also helpful for faster searches.
Examples
Update replica count
PUT /api-logs/_settings?pretty
{
"index" : {
"number_of_replicas" : 2
}
}Common problems
- By default, new replicas are not assigned to nodes with more than 85% disk usage. Instead, Elasticsearch throws a warning.
- Creating too many replicas may cause a problem if there are not enough resources available in the cluster.
Log Context
Log “expected mapper parsing failures. got” class name is TransportWriteAction.java. We extracted the following from Elasticsearch source code for those seeking an in-depth context :
throws Exception {
final Location location;
if (operationResult.getFailure() != null) {
// check if any transient write operation failures should be bubbled up
Exception failure = operationResult.getFailure();
assert failure instanceof MapperParsingException : "expected mapper parsing failures. got " + failure;
throw failure;
} else {
location = locationToSync(currentLocation; operationResult.getTranslogLocation());
}
return location;
