If your app spends most of its time reading — dashboards, analytics, content APIs — your PostgreSQL database needs a different architecture than a write-heavy OLTP system. We compared four managed services on how they handle read scaling, replica limits, and cloud lock-in. Amazon Aurora leads for most teams, but CockroachDB, Cloud SQL, and Aiven each have a clear niche.
Most PostgreSQL advice assumes a balanced read/write mix. But when your workload tilts heavily toward reads — think real-time dashboards, analytics queries, or serving content to thousands of concurrent users — the bottlenecks shift. You hit CPU saturation on the primary, lock contention on hot rows, and connection pool exhaustion.
The standard fix is read replicas: offload queries to copies of the database that stay in sync with the primary.1 But not all managed services implement replicas the same way. Some cap you at a handful of replicas. Others let you scale horizontally across regions. And some decouple compute from storage so replicas don't compete for the same underlying I/O.
Here's how the top managed PostgreSQL services stack up for read-heavy workloads.
| Pick | Best for | Scaling method | Replica limits | Cloud lock-in |
|---|---|---|---|---|
| Amazon Aurora PostgreSQL | Most teams with heavy read traffic | Horizontal (up to 15 read replicas) | 15 per cluster | High (AWS-only) |
| CockroachDB Dedicated | Multi-region reads & extreme horizontal scale | Horizontal (auto-sharded) | Unlimited (architectural) | Low (multi-cloud) |
| Google Cloud SQL for PostgreSQL | GCP-native teams needing simple replicas | Vertical + Horizontal (up to 10 replicas) | 10 per instance | High (GCP-only) |
| Aiven for PostgreSQL | Cloud-agnostic teams wanting flexibility | Horizontal (up to 10 replicas) | 10 per service | None (runs on AWS, GCP, Azure) |
Aurora's secret weapon is its decoupled storage layer. The primary and replicas share a distributed storage volume, so adding a replica doesn't copy data — it just spins up a new compute node pointing at the same storage.3 This means you can add up to 15 read replicas with near-zero replica lag, and each replica can serve thousands of concurrent queries without hammering the primary.
For read-heavy apps that stay within AWS, Aurora is the obvious choice. The Aurora Replicas can also serve as failover targets, giving you both read scaling and high availability in one cluster.
The trade-off: You're locked into AWS. And Aurora's PostgreSQL compatibility isn't 100% — some extensions and advanced Postgres features lag behind the community edition.
Specs:
CockroachDB isn't PostgreSQL under the hood, but it speaks the PostgreSQL wire protocol and supports most of the SQL surface area you'd expect.3 Its architecture is fundamentally different: data is automatically sharded across nodes, and every node can serve reads and writes. There's no "primary" bottleneck.
For read-heavy workloads that span multiple regions, CockroachDB shines. You can configure follower reads to serve stale-but-consistent reads from any replica in any region, dramatically reducing latency for a global user base.2
The trade-off: Transaction latency is higher than Aurora for single-region setups. And some PostgreSQL features (triggers, stored procedures in certain edge cases) behave differently. If you need Postgres exactly, this isn't it.
Specs:
Cloud SQL is the simplest managed Postgres on GCP. It supports up to 10 read replicas, and the replicas can be in different regions for disaster recovery.1 The setup is straightforward: enable the replica, point your read-only queries at the replica endpoint, and you're done.
Where Cloud SQL falls short is scale. The replica limit of 10 is lower than Aurora's 15, and you can't share storage between replicas the way Aurora does. Each replica is a full copy of the data, which means storage costs multiply.
The trade-off: Best for teams already on GCP who need a simple, well-integrated Postgres. Not ideal if you need massive read scaling or multi-cloud portability.
Specs:
Aiven runs on AWS, GCP, and Azure, and you can choose which cloud provider hosts your database. It supports up to 10 read replicas, and the management console makes it easy to spin up replicas in different regions or even different cloud providers.2
For teams that want to avoid vendor lock-in or need to run Postgres across multiple clouds, Aiven is the most flexible option. The trade-off is that you don't get the deep integration or performance optimizations of a cloud-native service like Aurora.
Specs:
| If you… | Go with… |
|---|---|
| Are all-in on AWS and need maximum read throughput | Amazon Aurora PostgreSQL |
| Need to serve reads globally with low latency | CockroachDB Dedicated |
| Run on GCP and want a simple, managed Postgres | Google Cloud SQL |
| Want to avoid cloud lock-in or run multi-cloud | Aiven for PostgreSQL |
A quick disclosure: some of the links on this page are affiliate links. If you sign up through them, we may earn a commission at no extra cost to you. We only recommend services we've researched thoroughly and would use ourselves.
For most teams building read-heavy applications, Amazon Aurora PostgreSQL is the sweet spot. The decoupled storage architecture solves the fundamental scaling problem — adding replicas doesn't compete for I/O — and 15 replicas is plenty for all but the most extreme workloads. If your read traffic goes truly global, CockroachDB's follower reads are worth the architectural trade-offs.
This page was written by the engine and the engine is still on the line. The conversation below picks up where the article stops.
Yes — the picks above are the engine's current verdicts. Ask a sharper version of this question below and you'll get a custom answer with the latest pricing.