SpringData ElasticSearch insert/update multiple documents - elasticsearch

Question

My goal is to do insert and update multiple documents in ElasticSearch using ElasticsearchRepository.
public interface EmployeeInfoRepository extends ElasticsearchRepository<EmployeeInfo, String> {
}
However, whenever I call saveAll(entities), the number of document is unchanged but it creates new indexes for those entities.
employeeInfoRepository.saveAll(employeeInfos);
If I insert 1000 elements, at first it will have 1000 docs and 1000 indexes, which is what I expected. Then I call saveAll two more times, it still has 1000 docs but now the number of indexes increases to 3000.
How can I update it properly?
It would be the best if it's just as easy as calling saveAll and the rest is handled by SpringBootData ElasticSearch.
Update 1:
There is no change with the data, however when I run saveAll, the storage_size keeps increasing. Not sure if it creates the indexes again and still keeps the old indexes.

Answer 1

If you define the id in your document class, elasticsearch updates/inserts the document with the same document id value.
Here an example:
#Document(indexName = "example_index")
public class Example {
#Id
#Field(type = FieldType.Long)
private long id;
}
Of course, you have to handle the logic for a unique id in your project.