Source filtering in Elasticsearch - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is source filtering in Elasticsearch?

Source filtering lets you choose which parts of the document you want to get back in the search results. It helps reduce the amount of data sent over the network.

beginner

How do you exclude fields using source filtering?

You use the _source field with an excludes list to tell Elasticsearch which fields to leave out from the results.

beginner

Show an example of including only specific fields with source filtering.

Use _source with an includes list. For example:<br>

{"_source": {"includes": ["title", "author"]}}

This returns only the title and author fields.

beginner

Why use source filtering in Elasticsearch?

It makes your search faster and lighter by sending only the data you need. This saves bandwidth and improves performance.

intermediate

Can source filtering be used with nested fields?

Yes, you can include or exclude nested fields by specifying their full path in the includes or excludes lists.

What does source filtering control in Elasticsearch?

A Which fields are returned in the search results

B Which documents are indexed

C How documents are scored

D The order of search results

Source filtering controls which fields are included or excluded in the search results.

How do you exclude the field 'password' from search results using source filtering?

A {"fields": ["password"]}

B {"_source": {"includes": ["password"]}}

C {"_source": {"excludes": ["password"]}}

D {"filter": {"password": false}}

Using excludes with the field name removes it from the returned source.

If you want only 'title' and 'date' fields in the results, which source filtering option is correct?

A {"_source": {"includes": ["title", "date"]}}

B {"_source": {"excludes": ["title", "date"]}}

C {"fields": ["title", "date"]}

D {"filter": {"title": true, "date": true}}

The includes list specifies which fields to return.

What happens if you do not use source filtering in a query?

A No fields are returned

B All fields of the document are returned

C Only the document ID is returned

D The query will fail

By default, Elasticsearch returns the entire source document.

Can source filtering improve network performance?

A Yes, but only for aggregations

B No, it only affects indexing

C No, it slows down queries

D Yes, by reducing data sent over the network

Source filtering reduces the size of the response, improving network performance.

Explain what source filtering is and why it is useful in Elasticsearch.

Think about how you can get only the parts of a document you need.

Describe how to include and exclude fields using source filtering with examples.

Remember the JSON keys 'includes' and 'excludes' inside '_source'.