Batch limits and best practices in Firebase - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ service_behavior

intermediate

Understanding Firestore Batch Write Limits

Firestore limits batch writes to a maximum number of operations per batch. What happens if you try to add 600 write operations in a single batch?

A The batch write fails with an error indicating the batch size exceeds the limit.

B The batch write automatically splits into multiple batches and commits them sequentially.

C The batch write commits only the first 500 operations and ignores the rest.

D The batch write succeeds and commits all 600 operations at once.

💡 Hint

Check Firestore documentation for batch write limits.

Firestore batch writes have a hard limit of 500 operations per batch. Trying to exceed this limit causes an error and the batch does not commit.

✅ Best Practice

intermediate

Best Practice for Large Batch Writes in Firestore

You need to write 1200 documents to Firestore. What is the best practice to handle this using batch writes?

A Split the writes into three batches of 400 operations each and commit them sequentially.

B Split the writes into three batches of 500, 500, and 200 operations and commit each batch separately.

C Create one batch with 1200 operations and commit it once.

D Write documents one by one without using batch writes.

💡 Hint

Remember the maximum operations per batch.

Since Firestore limits batch writes to 500 operations, splitting 1200 writes into batches of 500, 500, and 200 ensures all writes succeed without errors.

❓ security

advanced

Security Implications of Batch Writes in Firestore

When using batch writes in Firestore, which security best practice should you follow to avoid unintended data exposure or modification?

A Disable Firestore security rules during batch writes for performance.

B Use batch writes only on public collections without security rules.

C Ensure Firestore security rules validate each write operation within the batch individually.

D Use batch writes only with admin privileges to bypass security rules.

💡 Hint

Think about how security rules apply to batch writes.

Firestore security rules apply to each write in a batch individually. Ensuring rules validate each operation prevents unauthorized data changes.

❓ Configuration

advanced

Handling Partial Failures in Firestore Batch Writes

You submit a batch write with 400 operations. Some operations fail due to permission errors. What is the behavior of the batch commit?

A The batch commit fails entirely and no operations are applied.

B The batch commits all successful operations and skips failed ones.

C The batch commits only the operations before the first failure.

D The batch retries failed operations automatically until success.

💡 Hint

Consider atomicity of batch writes.

Firestore batch writes are atomic. If any operation fails, the entire batch fails and no changes are applied.

❓ Architecture

expert

Designing Scalable Batch Write Architecture for Firestore

You must design a system to process and write millions of records daily to Firestore using batch writes. Which architecture approach best ensures scalability and respects Firestore batch limits?

A Use a single server to queue all writes and send batches of 500 sequentially.

B Use Firestore triggers to batch writes automatically after receiving individual writes.

C Write all records individually without batching to avoid batch limits.

D Distribute write tasks across multiple workers, each handling batches of 500 writes concurrently.

💡 Hint

Think about concurrency and batch size limits.

Distributing write tasks across multiple workers allows concurrent batch writes, improving throughput while respecting Firestore's 500-operation batch limit.