Retrieving a document by ID in Elasticsearch - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to retrieve a document by its ID using Elasticsearch's GET API.

Elasticsearch

GET /my_index/_doc/[1]

Drag options to blanks, or click blank then click option'

A123

Bindex

Cquery

Dsearch

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'search' or 'query' instead of the document ID.

Confusing the index name with the document ID.

The GET API requires the document ID to retrieve the specific document. Here, '123' is the document ID.

2fill in blank

medium

Complete the JSON body to retrieve a document by ID using the Elasticsearch _search API with a term query.

Elasticsearch

{
  "query": {
    "term": { "_id": "[1]" }
  }
}

Drag options to blanks, or click blank then click option'

Aexists

Bmatch_all

Cuser_1

Drange

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'match_all' which returns all documents.

Using 'exists' or 'range' which are not for exact ID matching.

The term query on '_id' requires the exact document ID, such as 'user_1'.

3fill in blank

hard

Fix the error in the code to correctly retrieve a document by ID using the Elasticsearch Python client.

Elasticsearch

response = client.get(index="products", id=[1])

Drag options to blanks, or click blank then click option'

Aabc123

B"abc123"

Cindex

Ddoc_id

Attempts:

3 left

💡 Hint

Common Mistakes

Passing the ID without quotes causing a syntax error.

Using variable names that are not defined.

The document ID must be a string, so it needs quotes around it like "abc123".

4fill in blank

hard

Fill both blanks to complete the curl command that retrieves a document by ID from Elasticsearch.

Elasticsearch

curl -X [1] "http://localhost:9200/[2]/_doc/42"

Drag options to blanks, or click blank then click option'

AGET

BPOST

Cmy_index

Dsearch

Attempts:

3 left

💡 Hint

Common Mistakes

Using POST instead of GET.

Using 'search' instead of the index name.

The GET method is used to retrieve documents, and 'my_index' is the index name.

5fill in blank

hard

Fill all three blanks to complete the Elasticsearch query that retrieves a document by ID using the REST API with a JSON body.

Elasticsearch

{
  "query": {
    "[1]": {
      "[2]": "[3]"
    }
  }
}

Drag options to blanks, or click blank then click option'

Aterm

B_id

Cdoc_789

Dmatch

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'match' instead of 'term' for exact ID matching.

Using a field other than '_id' to filter by document ID.

The 'term' query is used for exact matches, '_id' specifies the document ID field, and 'doc_789' is the document ID.

Practice

1. What is the fastest way to retrieve a single document in Elasticsearch?

easy

A. Retrieve the document by its ID using the GET API

B. Search all documents with a match_all query

C. Use a scroll API to iterate over documents

D. Run an aggregation query on the index

Solution

1. Step 1: Understand retrieval methods

   Retrieving by ID directly targets one document, making it the fastest method.

2. Step 2: Compare with other methods

   Search queries and scroll APIs scan multiple documents, which is slower than direct ID retrieval.

3. Final Answer:

   Retrieve the document by its ID using the GET API -> Option A

4. Quick Check:

   Fastest retrieval = GET by ID [OK]

Hint: Use GET API with document ID for fastest retrieval [OK]

Common Mistakes:

• Thinking search queries are faster than direct ID retrieval
• Using scroll API for single document retrieval
• Confusing aggregation with document retrieval

2. Which of the following is the correct syntax to retrieve a document by ID in Elasticsearch?

easy

A. GET /index/_doc/123

B. GET /index/_search {"query": {"term": {"_id": "123"}}}

C. POST /index/_doc/123/_get

D. GET /index/_search/123

Solution

1. Step 1: Recall the GET by ID syntax

   The correct syntax uses GET with the index and document ID: GET /index/_doc/123

2. Step 2: Identify incorrect options

   GET /index/_search {"query": {"term": {"_id": "123"}}} uses a search query, not direct GET by ID. POST /index/_doc/123/_get uses POST and an invalid path. GET /index/_search/123 has an invalid URL structure.

3. Final Answer:

   GET /index/_doc/123 -> Option A

4. Quick Check:

   Correct syntax = GET /index/_doc/ID [OK]

Hint: Use GET /index/_doc/{id} to retrieve document by ID [OK]

Common Mistakes:

• Using search API instead of GET by ID
• Wrong HTTP method like POST
• Incorrect URL path structure

3. Given the following request, what will Elasticsearch return if the document with ID 'abc123' exists?

GET /products/_doc/abc123

medium

A. HTTP 404 Not Found

B. {"_index":"products","_id":"abc123","found":false}

C. {"_index":"products","_id":"abc123","found":true,"_source":{"name":"Laptop","price":1200}}

D. {"error":"Document not found"}

Solution

1. Step 1: Understand the GET by ID response

   If the document exists, Elasticsearch returns found: true with the document source.

2. Step 2: Match the response format

   {"_index":"products","_id":"abc123","found":true,"_source":{"name":"Laptop","price":1200}} shows found: true and the document data, which matches expected output.

3. Final Answer:

   {"_index":"products","_id":"abc123","found":true,"_source":{"name":"Laptop","price":1200}} -> Option C

4. Quick Check:

   Document exists = found: true with _source [OK]

Hint: Found true means document exists with _source data [OK]

Common Mistakes:

• Expecting HTTP 404 instead of found: false
• Confusing error message with standard response
• Ignoring the _source field in response

4. You run this request to get a document by ID but get an error:

GET /store/_doc

What is the problem and how to fix it?

medium

A. The _doc endpoint does not support GET requests

B. Wrong HTTP method; use POST instead of GET

C. Index name is incorrect; change 'store' to '_store'

D. Missing document ID in URL; add the ID after _doc

Solution

1. Step 1: Identify the request format

   The GET by ID request requires the document ID after _doc in the URL.

2. Step 2: Fix the URL

   Add the document ID after _doc, e.g., GET /store/_doc/123

3. Final Answer:

   Missing document ID in URL; add the ID after _doc -> Option D

4. Quick Check:

   GET by ID needs document ID in URL [OK]

Hint: Always include document ID after _doc in GET URL [OK]

Common Mistakes:

• Omitting document ID in GET request URL
• Using wrong HTTP method
• Misnaming the index with underscore

5. You want to retrieve a document by ID but also handle the case when the document is missing without causing an error. Which approach is best?

hard

A. Use a search query with term _id and expect zero hits if missing

B. Use GET /index/_doc/id and check if 'found' is true in the response

C. Use GET /index/_doc/id and catch HTTP 404 error to handle missing

D. Use scroll API to find the document and handle empty results

Solution

1. Step 1: Understand GET by ID response behavior

   GET by ID returns a JSON with 'found': false if the document is missing, no error thrown.

2. Step 2: Compare with other methods

   Search queries return hits but are slower; catching HTTP 404 is unnecessary; scroll API is for multiple docs.

3. Final Answer:

   Use GET /index/_doc/id and check if 'found' is true in the response -> Option B

4. Quick Check:

   Check 'found' field to detect missing document [OK]

Hint: Check 'found' in GET response to detect missing docs safely [OK]

Common Mistakes:

• Expecting HTTP 404 error for missing documents
• Using search queries instead of GET by ID
• Using scroll API for single document retrieval