Deleting documents in Elasticsearch - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the basic way to delete a document in Elasticsearch?

You delete a document by specifying its index and ID using the DELETE API, like: <br>DELETE /index_name/_doc/document_id

beginner

What happens if you try to delete a document that does not exist?

Elasticsearch returns a successful response with result: "not_found", meaning the document was not found but no error occurs.

intermediate

How can you delete multiple documents matching a query?

Use the _delete_by_query API with a query to delete all documents matching that query in an index.

intermediate

What is the difference between DELETE /index/_doc/id and POST /index/_delete_by_query?

DELETE /index/_doc/id deletes a single document by ID.<br>_delete_by_query deletes all documents matching a query, potentially many at once.

intermediate

Why should you be careful when using _delete_by_query?

Because it can delete many documents at once, possibly more than intended, so always test your query carefully before running it.

Which HTTP method is used to delete a single document by ID in Elasticsearch?

A GET

B POST

C DELETE

D PUT

The DELETE method is used to remove a document by its ID.

What does Elasticsearch return if you delete a document that does not exist?

A result: 'not_found'

B An error

C result: 'deleted'

D No response

Elasticsearch returns a successful response with result 'not_found' if the document is missing.

Which API allows deleting multiple documents matching a query?

A _delete_all

B _bulk_delete

C _delete_by_id

D _delete_by_query

The _delete_by_query API deletes all documents matching a query.

What is a key risk when using _delete_by_query?

A It can delete more documents than intended

B It cannot delete documents

C It requires no query

D It deletes only one document

If the query is too broad, _delete_by_query can delete many documents unintentionally.

How do you specify the document to delete in the DELETE API?

A By query only

B By index and document ID

C By document content

D By document size

You specify the index and the document ID to delete a single document.

Explain how to delete a single document in Elasticsearch and what happens if the document does not exist.

Think about the HTTP method and response.

Describe the _delete_by_query API and why you should use it carefully.

Consider bulk deletion and query safety.