Bulk API for batch operations in Elasticsearch - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

What is the output of this Bulk API request?

Consider the following Bulk API request sent to Elasticsearch. What will be the result in the response for the items array?

Elasticsearch

{ "index": { "_index": "products", "_id": "1" } }
{ "name": "Laptop", "price": 1200 }
{ "delete": { "_index": "products", "_id": "2" } }
{ "update": { "_index": "products", "_id": "3" } }
{ "doc": { "price": 900 } }

A The response will contain 4 items: one index success, one delete success, one update success, and one error because the update body is missing the 'doc' key.

B The response will contain 3 items: index success, delete success, and an error for the update because the update body is malformed.

C The response will contain 4 items: index success, delete success, update success, and an error because the delete operation is missing a body.

D The response will contain 3 items: index success, delete success, and update success with the price updated to 900.

💡 Hint

Remember that each action line must be followed by its data line except for delete operations which do not require a data line.

The Bulk API expects each action line to be followed by a data line except for delete operations which do not have a data line. Here, the delete operation is correctly formatted without a data line. The update operation includes a proper 'doc' field. So the response will have 3 items corresponding to the 3 operations: index, delete, and update, all successful.

🧠 Conceptual

intermediate

How does the Bulk API handle partial failures?

When sending a Bulk API request with multiple operations, how does Elasticsearch handle partial failures?

A Elasticsearch processes all operations and returns individual success or failure status for each operation in the response.

B Elasticsearch ignores failures and returns success for all operations regardless of errors.

C Elasticsearch retries failed operations automatically until they succeed or a timeout occurs.

D Elasticsearch stops processing at the first failure and returns an error for the entire bulk request.

💡 Hint

Think about how batch processing usually reports results.

The Bulk API processes all operations in the batch and returns a response with an array of items. Each item shows whether that specific operation succeeded or failed. This allows clients to handle partial failures gracefully.

🔧 Debug

advanced

Identify the error in this Bulk API request

Review the following Bulk API request. What error will Elasticsearch return?

Elasticsearch

{ "index": { "_index": "users", "_id": "10" } }
{ "name": "Alice" }
{ "update": { "_index": "users", "_id": "11" } }
{ "price": 100 }
{ "delete": { "_index": "users", "_id": "12" } }
{ "index": { "_index": "users", "_id": "13" } }

A A syntax error because the last index operation is missing its data line.

B An error because the update operation's data line is missing the 'doc' key.

C An error because the delete operation has an unexpected data line following it.

D No error; all operations are valid and will succeed.

💡 Hint

Check if every action line that requires a data line has one.

The last index operation is missing its data line. Every index operation must be followed by a data line with the document to index. This causes a parsing error in the Bulk API request.

📝 Syntax

advanced

Which Bulk API request syntax is correct?

Choose the correct Bulk API request syntax to update a document with ID '5' in index 'orders' to set the field 'status' to 'shipped'.

A

{ "doc": { "status": "shipped" } }
{ "update": { "_index": "orders", "_id": "5" } }

B

{ "update": { "_index": "orders", "_id": "5" } }
{ "doc": { "status": "shipped" } }

C

{ "update": { "_index": "orders", "_id": "5" } }
{ "status": "shipped" }

D { "update": { "_index": "orders", "_id": "5", "doc": { "status": "shipped" } } }

💡 Hint

Remember the Bulk API requires an action line followed by a data line for update operations.

The correct syntax for an update operation in the Bulk API is an action line specifying the update and a data line containing the 'doc' field with the partial document to update. Option B follows this format correctly.

🚀 Application

expert

How many items will be in the response for this Bulk API request?

Given the following Bulk API request with 4 action lines, how many items will the response contain?

Elasticsearch

{ "index": { "_index": "logs", "_id": "100" } }
{ "message": "start" }
{ "delete": { "_index": "logs", "_id": "101" } }
{ "update": { "_index": "logs", "_id": "102" } }
{ "doc": { "status": "done" } }
{ "index": { "_index": "logs", "_id": "103" } }
{ "message": "end" }

A 3 items, because the last index operation is missing a data line and will cause an error.

B 5 items, one for each action line.

C 4 items, because delete operations do not have a data line and are counted as one item.

D 6 items, counting both action and data lines separately.

💡 Hint

Count the number of operations, not lines, and remember delete operations do not have data lines.

The Bulk API response contains one item per operation. Here, there are 4 operations: index (id 100), delete (id 101), update (id 102), and index (id 103). Each operation corresponds to one item in the response. The delete operation does not have a data line but counts as one operation. So the response will have 4 items.