Retrieving a document by ID in Elasticsearch - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

What is the output of this Elasticsearch GET request?

Given the following Elasticsearch GET request to retrieve a document by ID, what will the response be?

Elasticsearch

GET /library/_doc/123

A {"_index": "library", "_id": "123", "found": true, "_source": {"title": "Learn Elasticsearch", "author": "Jane Doe"}}

B {"error": "document missing"}

C {"_id": "123", "found": false}

D {"title": "Learn Elasticsearch", "author": "Jane Doe"}

💡 Hint

The GET request returns a JSON object with metadata and the document source inside the _source field.

When you retrieve a document by ID in Elasticsearch, the response includes metadata like _index, _id, and a found flag. The actual document content is inside the _source field.

🧠 Conceptual

intermediate

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

You want to get a document from Elasticsearch by its ID. Which HTTP method should you use?

A POST

B GET

C PUT

D DELETE

💡 Hint

Think about which HTTP method is used to fetch data without changing it.

The GET method is used to retrieve data from a server without modifying it. Elasticsearch uses GET to fetch documents by ID.

🔧 Debug

advanced

Why does this Elasticsearch GET request return a 404 error?

You run this request: GET /books/_doc/999 But you get a 404 error. What is the most likely reason?

A The HTTP method GET is not supported for document retrieval.

B The index name 'books' is misspelled and does not exist.

C The document with ID 999 does not exist in the 'books' index.

D The request body is missing.

💡 Hint

A 404 error means the resource was not found.

A 404 error when retrieving a document by ID usually means the document does not exist in the specified index.

📝 Syntax

advanced

Which of these is the correct syntax to retrieve a document by ID in Elasticsearch?

Choose the correct Elasticsearch GET request syntax to retrieve a document with ID 'abc123' from the index 'products'.

A GET /products/_doc/abc123

B GET /products/_search/abc123

C POST /products/_doc/abc123

D GET /products/doc/abc123

💡 Hint

The correct path includes the index, the type '_doc', and the document ID.

The correct syntax uses GET, the index name, '_doc' as the type, and the document ID.

🚀 Application

expert

How to retrieve multiple documents by ID in a single Elasticsearch request?

You want to get documents with IDs '1', '2', and '3' from the 'users' index in one request. Which Elasticsearch API and request body should you use?

A Send three separate GET requests for each ID.

B Use the GET API with a comma-separated list: GET /users/_doc/1,2,3

C Use the _search API with a query matching the IDs.

D Use the _mget API with a JSON body listing the IDs.

💡 Hint

Elasticsearch has a special API for multiple document retrieval by IDs.

The _mget API allows retrieving multiple documents by specifying their IDs in a JSON body in a single request.