# Logstash Extract Elasticsearch Nested Fields

**URL:** <https://discuss.elastic.co/t/logstash-extract-elasticsearch-nested-fields/275451>\
**Category:** Logstash\
**Created:** [June 9, 2021, 2:17pm UTC](https://discuss.elastic.co/t/logstash-extract-elasticsearch-nested-fields/275451 "2021-06-09T14:17:28Z")\
**Posts on this page:** 1\
**Showing post:** 23

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**Author:** ![Badger](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/badger/32/25190_2.png) [@Badger](https://discuss.elastic.co/u/Badger)\
**Post date:** [June 16, 2021, 3:44am UTC](https://discuss.elastic.co/t/logstash-extract-elasticsearch-nested-fields/275451/23 "2021-06-16T03:44:46Z")

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Possibly use a prune filter where the [default](https://www.elastic.co/guide/en/logstash/current/plugins-filters-prune.html#plugins-filters-prune-blacklist_names) value for blacklist\_names will delete fields where a sprintf reference failed. I think the unresolved sprintf reference will be top-level so then you should get an empty field.

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_[View the full topic](https://discuss.elastic.co/t/logstash-extract-elasticsearch-nested-fields/275451)._