Your Database is Your Single Point of Failure. CockroachDB Was Built to Survive Anything.
For decades, developers have been forced into a false choice: the familiar, consistent world of relational SQL databases (like PostgreSQL), or the scalable but complex world of NoSQL. CockroachDB was built to shatter that choice. It is a distributed SQL database that speaks the PostgreSQL wire protocol, offering the familiar comfort of relational schemas and ACID transactions, but with the horizontal scalability and "unkillable" resilience of a modern, cloud-native distributed system.
But this power requires a new way of thinking. An engineer who approaches CockroachDB as "just PostgreSQL" will miss its most powerful features and, worse, may design a system that performs poorly at scale. They might fail to understand the implications of data locality, choose a poor primary key strategy that leads to hotspots, or write transactions that suffer from contention in a distributed environment.
An engineer who can write a `SELECT` statement is not a CockroachDB expert. An expert understands how ranges and replicas work. They can design a schema with locality-optimized data topologies. They know how to write efficient, contention-reducing transactions. They treat CockroachDB not just as a database, but as a resilient, self-healing platform. This playbook explains how Axiom Cortex finds engineers who have this deep, distributed SQL mindset.
Traditional Vetting and Vendor Limitations
A nearshore vendor sees "CockroachDB" or "Distributed SQL" on a résumé and assumes competence. The interview will likely consist of generic PostgreSQL questions, completely missing the point of what makes CockroachDB special and challenging.
The predictable and painful results of this flawed vetting are common:
- Hotspot Headaches: A developer uses a sequential primary key for a high-write table, causing all writes to be directed to a single range "leaseholder," creating a performance bottleneck and nullifying the database's scalability.
- Cross-Region Latency Nightmares: An application running in a multi-region cluster experiences terrible performance because the team did not design their data topology to co-locate data with the users who access it most, leading to high-latency cross-region queries for every request.
- Transaction Contention: A long-running transaction holds locks on a wide range of rows, causing other transactions to fail with retry errors, leading to a poor user experience and complex application-level error handling.
- Ignoring Resilience: The team treats the database as if it were a single-node instance, failing to design their application to handle the transient errors and transaction retries that are a natural part of working with a distributed, fault-tolerant system.
How Axiom Cortex Evaluates CockroachDB Developers
Axiom Cortex is designed to find engineers who think in terms of resilience, locality, and distributed transactions. We test for the practical skills that are essential for building scalable and bulletproof applications on CockroachDB. We evaluate candidates across four critical dimensions.
Dimension 1: Distributed Data Modeling and Schema Design
This is the most critical skill for a CockroachDB developer. Performance and resilience are designed at the schema level.
We provide a business problem and evaluate their ability to:
- Design a Hotspot-Resistant Schema: Can they choose a primary key strategy (like using UUIDs or hash-sharded indexes) that will evenly distribute writes across the cluster?
- Plan a Data Topology: For a multi-region application, can they design a schema that uses CockroachDB's geo-partitioning features to pin data to specific regions, minimizing latency for users?
- Leverage PostgreSQL Compatibility: Do they know how to use the familiar features of PostgreSQL (like JSONB, GIN indexes, and window functions) effectively within the CockroachDB environment?
Dimension 2: Performance Tuning and Query Optimization
This dimension tests a candidate's ability to write fast queries and diagnose performance issues in a distributed SQL environment.
We present a slow query or a high-contention scenario and evaluate if they can:
- Analyze a Distributed `EXPLAIN` Plan: Can they read the execution plan to understand how a query is being executed across multiple nodes and identify performance bottlenecks?
- Design an Indexing Strategy: Do they understand how to create secondary indexes and when to use features like storing indexes to improve query performance?
Dimension 3: Resilience and Transaction Management
CockroachDB is designed to survive failures. An elite developer must write application code that can do the same.
We evaluate their ability to:
- Write Retry-Aware Transactions: Can they write application code that correctly handles CockroachDB's serializable transaction isolation level and automatically retries transactions that fail due to contention?
- Understand Consistency Guarantees: Can they explain how CockroachDB provides strong consistency and how to use features like follower reads for low-latency, slightly stale reads when appropriate?
Dimension 4: Operations and Observability
An elite CockroachDB developer understands how to operate and monitor the cluster.
Axiom Cortex assesses a candidate's knowledge of:
- The DB Console: Are they familiar with using the CockroachDB DB Console to monitor cluster health, identify hotspots, and debug slow queries?
- Scaling and Topology Changes: Can they explain the process for adding or removing a node from a live cluster?
From a Bottleneck to a Bulletproof Platform
When you staff your team with engineers who have passed the CockroachDB Axiom Cortex assessment, you are investing in a team that can build truly resilient, globally scalable applications.
A gaming company wanted to build a global leaderboard system that required both strong consistency and low latency for users across the world. Their existing PostgreSQL database could not handle the load or the geographic distribution. By assembling a pod of two elite nearshore CockroachDB developers, they were able to build a new system on a multi-region CockroachDB cluster that not only scaled to handle millions of players but could also survive the failure of an entire cloud region with zero downtime.
What This Changes for CTOs and CIOs
Using Axiom Cortex to hire for CockroachDB competency is about moving beyond the limitations of traditional databases. It is a strategic move to build applications that are resilient by design and can scale globally without sacrificing the strong consistency that your business logic depends on.