Failed to serialize source for type type – How to solve this Elasticsearch exception

Opster Team

August-23, Version: 6.8-7.13

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Briefly, this error occurs when Elasticsearch is unable to convert the source data into a format suitable for indexing, for a specific type. This could be due to incorrect data types, malformed data, or incompatible mapping. To resolve this issue, you can: 1) Check and correct the data types in your source data. 2) Validate your data to ensure it’s correctly formatted. 3) Review and update your index mapping to match the source data structure. 4) If the error persists, consider reindexing your data.

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This guide will help you check for common problems that cause the log ” failed to serialize source for type [” + type + “] ” to appear. To understand the issues related to this log, read the explanation below about the following Elasticsearch concepts: index, source.

Log Context

Log “failed to serialize source for type [” + type + “]” class name is We extracted the following from Elasticsearch source code for those seeking an in-depth context :

 this.mappingLookup = MappingLookup.fromMapping(mapping; documentParser; indexSettings; indexAnalyzers);  try {
 mappingSource = new CompressedXContent(mapping; XContentType.JSON; ToXContent.EMPTY_PARAMS);
 } catch (Exception e) {
 throw new ElasticsearchGenerationException("failed to serialize source for type [" + type + "]"; e);
 }  final Collection deleteTombstoneMetadataFields = Arrays.asList(VersionFieldMapper.NAME; IdFieldMapper.NAME;
 TypeFieldMapper.NAME; SeqNoFieldMapper.NAME; SeqNoFieldMapper.PRIMARY_TERM_NAME; SeqNoFieldMapper.TOMBSTONE_NAME);
 this.deleteTombstoneMetadataFieldMappers = Stream.of(mapping.getSortedMetadataMappers())


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