Prev Next

Database / Google Spanner Database Interview questions

What is the Spanner emulator?

The Cloud Spanner emulator is a local, in-memory version of Spanner that implements the same gRPC API as the production service, letting developers write and test code without connecting to a real instance or incurring cost.

gcloud emulators spanner start
gcloud config set auth/disable_credentials true
gcloud config set api_endpoint_overrides/spanner http://localhost:9020/

It supports DDL, DML, mutations, and transactions, making it suitable for unit tests and CI pipelines. It does not enforce real replication, TrueTime uncertainty, or performance characteristics, so latency-sensitive or scale-related behavior still needs to be validated against a real instance before production rollout.

What is the main benefit of the Spanner emulator?
What does the emulator NOT accurately reproduce?

More Related questions...

What is Google Cloud Spanner? What are the main features of Google Spanner? What is the purpose of TrueTime in Spanner? Define interleaved tables in Google Spanner? What is a Spanner instance? What are processing units in Google Spanner? Describe primary keys in Google Spanner schema design? What are the supported database dialects in Spanner? List the data types supported by Google Spanner? How do you create a database in Google Spanner? What is a secondary index in Spanner? Explain the purpose of splits in Spanner? What are mutations in Google Spanner? How do you apply schema changes in Spanner? What is the Spanner emulator? Why does Spanner use TrueTime for consistency? How does Spanner achieve external consistency? What is the difference between read-write and read-only transactions in Spanner? When should you use interleaved tables versus foreign keys? What happens when a hotspot occurs in Spanner? How is data partitioned across nodes in Spanner? Why should you avoid monotonically increasing primary keys? What is the difference between Spanner and Cloud SQL? How does Spanner handle schema changes without downtime? When would you choose bounded staleness over strong reads? How can you optimize query performance in Spanner? What is the difference between Data Boost and standard reads? Why do we use commit timestamps in Spanner tables? How does Spanner's query optimizer choose an execution plan? What is the difference between batch DML and partitioned DML? When should you use change streams in Spanner? How is fine-grained access control implemented in Spanner? Why doesn't Spanner support auto-incrementing primary keys? What is the difference between GoogleSQL and PostgreSQL dialects in Spanner? How do you troubleshoot high latency in Spanner queries? Explain the internal working of Paxos in Spanner replication? Explain the execution flow of a read-write transaction in Spanner? Explain the lifecycle of a split in Spanner? How does Spanner guarantee external consistency across regions? What happens internally when Spanner commits a distributed transaction? How can you optimize a multi-region Spanner configuration for latency? Which is better and why: multi-region or regional Spanner configuration for a global app? How does directed reads improve read latency in multi-region Spanner? Why is clock skew uncertainty critical to Spanner's TrueTime API? How do you troubleshoot transaction aborts in Spanner? Explain the internal working of the Spanner query execution engine? What happens when a leader region becomes unavailable in Spanner? How does Spanner implement point-in-time recovery internally? Explain the execution flow of a partitioned DML statement in Spanner? How can you optimize schema design to avoid hotspotting at scale?
Show more question and Answers...

ScyllaDB Interview questions

Comments & Discussions

Interviews Questions

About Javapedia.net

Javapedia.net is for Java and J2EE developers, technologist and college students who prepare of interview. Also this site includes many practical examples.

This site is developed using J2EE technologies by Steve Antony, a senior Developer/lead at one of the logistics based company.

Follow Javapedia updates

contact: javatutorials2016[at]gmail[dot]com

Kindly consider donating for maintaining this website. Thanks.

Copyright © 2026, javapedia.net, all rights reserved. · .

DMCA.com Protection Status