Elastic mappings support up to 7,000,000 input and output fields. All mappings are subject to this limit. However, mappings that include the Hierarchy Processor transformation are more likely to approach the limit because of the complex data involved.

The more joins, child fields, nested fields, and flattened arrays that the Hierarchy Processor transformation contains, the more likely the mapping will exceed the field limit.

If the mapping exceeds the limit, the following message appears in the mapping compilation log:

[LDTM_0502] The mapping [<mapping name>] failed because the number of fields in the compiled mapping exceeds the threshold: [7,000,000]. Number of fields: [<actual number>]. Create multiple mappings to process the data incrementally.

To resolve the error, create multiple mappings to process the complex data incrementally or reduce the size of the mapping.