date. When you synchronize data from an existing ES cluster to an index in the ES Serverless service, if the field in the data has the same name as the time field but a different type, the write operation will fail. In this case, you can use the Reindex API to convert the field type.date if the field has the same name as the time field in the ES Serverless service index.source_index to an index in the ES Serverless service (where the time field is @timestamp). Upon checking the field configuration of source_index, we find that in source_index, the field @timestamp is of type keyword. In this case, attempting to synchronize the data will result in a write error.

dest_index for reindexing, and specify the type of the @timestamp field in the mapping as date.
source_index to dest_index, and the number of documents in dest_index should match exactly the number in the original source_index.POST _reindex{"source": {"index": "source_index"},"dest": {"index": "dest_index"}}

dest_index will retrieve the data that was synchronized from source_index.
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