An Engineer's Guide to DuckDB and Modern OLAP Databases

TL;DR

• Cloud warehouses are built for petabyte-scale enterprise needs, and for teams working with a few terabytes, they are architectural overkill.
• Your production database is not the answer either. Running analytical queries on Postgres creates I/O bottlenecks that can take down your application.
• DuckDB runs locally, requires no infrastructure, and handles sub-terabyte data fast, making it a better fit for the majority of analytical workloads.
• Serverless options like MotherDuck extend DuckDB to the cloud without the billing surprises of legacy warehouses. The practical split is Postgres for transactions, DuckDB for local analytics, and MotherDuck to scale and share those workflows.

I still remember the Slack message that popped up at 2:17 AM. It was from finance, and it was a screenshot of our latest Snowflake bill with a single question mark. The number had a comma in a place that made my stomach drop. We had run a backfill and some exploratory queries, and suddenly we were staring down a five-figure invoice that nobody could explain. We were paying a premium for a petabyte-scale engine, but our actual data was a few terabytes at most.

You have probably felt this pain, too. The tools the industry tells us to use for data analytics, these massive, client-server cloud warehouses, are often a mismatch for the job at hand. This architectural mismatch creates two problems: unpredictable, spiraling costs and painful workflow friction that kills developer productivity.

This is my honest breakdown of data warehouse architecture, covering what I tried, what didn’t work, and what finally did.

The Evolution of Data Warehouses

Most of us have walked the same path, graduating from one level of complexity to the next, often without questioning the fundamental trade-offs we were making.

This journey usually happens in four stages. It starts with convenience, moves to supposed necessity, discovers a faster alternative in embedded OLAP, and lands on scaling those local workflows with a specialized warehouse.

Approach comparison: at a glance

This is the data analytics maturity curve I have seen play out at company after company.

The Ad-hoc Era: Using your OLTP database (Postgres) for analytics

My first brush with this problem was a 3 AM page for a Postgres database that had fallen over. An analyst had kicked off a massive query to calculate quarterly growth, and it brought our customer-facing application to its knees.

Using your production OLTP database for analytics is tempting. The data is already there, and everyone on the team knows its flavor of SQL. But it is an architectural mismatch waiting to cause an outage.

Postgres is a row-store database, optimized for transactions (OLTP). Think of your data like a filing cabinet. When a user signs up, Postgres grabs a single drawer (a row) and writes all their information into it. This is fast and efficient for transactional operations.

An analytical query needs to find one specific folder (a column) inside every single drawer. To calculate the average order_value, Postgres is forced to pull every single drawer from the cabinet and read the entire contents, even though it only needs one piece of information from each. This creates a massive I/O bottleneck.

This is a fundamental design limitation, and no amount of indexing or query tuning will fix it.

Bridging the gap with the pg_duckdb extension

There is a pragmatic middle ground for teams who want to keep their data in Postgres but need faster analytics. The pg_duckdb extension lets you run DuckDB's vectorized execution engine directly inside Postgres, accelerating analytical queries without moving your data to a separate system. The speed gains vary depending on your workload, but the real advantage is simpler operations since it doesn’t require an ETL pipeline or a separate database to manage.

If you do try it, run this on a read-replica. Using it on your primary instance is a faster way to starve your transactional workloads and get yourself paged at 3 AM.

The Monolithic Era: The enterprise cloud data warehouse (Snowflake)

As your data needs outgrow Postgres, you eventually graduate to the next tier. You get a budget and sign a contract with Snowflake or BigQuery. Historically, for true petabyte-scale, Snowflake was the only game in town. It solved the production-impact problem by separating analytics from your transactional database.

That has changed. Serverless DuckDB architectures like MotherDuck's Managed DuckLake now support petabyte-scale data via object storage like S3, which shifts the calculus for teams evaluating Snowflake alternatives.

For the vast majority of us working with sub-terabyte to low-terabyte datasets, the monolithic cloud warehouse is architectural overkill. The core issue is the 60-second billing minimum that Snowflake enforces every time a suspended warehouse wakes up. I think of this as an "architectural cost floor."

If an automated high-frequency workload (like a BI dashboard) continually triggers this 60-second wake-up minimum, a query that takes 200 milliseconds to run still costs you 60 seconds of compute. That math works against anyone with bursty or intermittent workloads. Add in opaque "cloud services" charges and warehouses accidentally left running without auto-suspend, and you get the surprise bill I mentioned earlier.

And then there is the day-to-day friction. I remember waiting 90 seconds for my Snowflake warehouse to resume so I could run a 5-second query. This latency breaks your flow state and discourages exploration.

The analytics company Definite migrated its entire platform from Snowflake to DuckDB. They reduced infrastructure costs by over 70% and saw faster queries after a two-week migration. Organizations can achieve an approximately 70% reduction in cloud data warehouse costs by moving appropriate workloads to DuckDB. Price-performance benchmarks confirm this. DuckDB running on cloud VMs could be 55-77% cheaper than equivalently sized Snowflake warehouses for identical workloads.

A pragmatic middle ground: The DuckDB Snowflake Extension

If you are not ready to rip and replace, there is a bridge. The DuckDB Snowflake Extension lets you run federated queries, pulling data from Snowflake into your local DuckDB process for analysis. It is a great tool for iterative local development on subsets of your cloud data. But be clear-eyed about what it solves. You still pay for the Snowflake compute credits required to serve the data every time you pull it down.

Benefits and Use Cases for DuckDB

For a huge class of problems, DuckDB suits so well that it almost feels unfair.

The "in-process" advantage

The core innovation of DuckDB is that it is an "in-process" OLAP database. There is no server to install or cluster to provision. You pip install duckdb, and you have a complete analytical engine running inside your Python script or your CI/CD runner:

import duckdb
con = duckdb.connect()
con.execute("SELECT * FROM 'my_data.parquet' LIMIT 5").show()

You are now running analytics directly on a Parquet file, with no ingestion step required. Your complex PostgreSQL analytical queries also map directly to DuckDB. The same heavy Common Table Expressions (CTEs) and window functions that choked your Postgres instance run in seconds, right here:

con.execute("""
    WITH monthly_sales AS (
        SELECT 
            customer_id,
            DATE_TRUNC('month', order_date) AS month,
            SUM(order_value) AS total_value
        FROM 'orders.parquet'
        GROUP BY 1, 2
    )
    SELECT 
        customer_id,
        month,
        total_value,
        AVG(total_value) OVER (
            PARTITION BY customer_id 
            ORDER BY month 
            ROWS BETWEEN 2 PRECEDING AND CURRENT ROW
        ) AS rolling_3m_avg
    FROM monthly_sales;
""").show()

DuckDB has high Postgres compatibility, so your senior-level SQL syntax migrates with ease. That said, watch for behavioral differences. For example, DuckDB conforms strictly to the IEEE 754 standard for floating-point arithmetic. Dividing a float by zero returns Infinity, whereas Postgres will throw a hard division-by-zero error.

Why is it so fast?

DuckDB's speed comes from two main architectural choices: columnar storage and vectorized execution. We have discussed the columnar advantage of only reading the data you need. Vectorized execution is how it processes that data.

Think of it like processing LEGO bricks. A traditional row-based database evaluates them one by one. A vectorized engine grabs a whole chunk of bricks and processes them simultaneously using optimized CPU instructions (Single Instruction, Multiple Data). Rather than evaluating data row-by-row, it applies a single instruction to an entire array of data at once. This efficiency is dramatic. DuckDB achieves 10-100x more frequent CPU cache hits and uses 3.8x less memory bandwidth compared to Postgres.

Honest Limitations: When I would avoid DuckDB

To trust a tool, you have to know its limits. DuckDB is architecturally bound to a single node. It does not have native clustering for high availability. It is not designed for high-concurrency transactional workloads (that is what Postgres is for). It also does not have built-in data access controls like row-level security. Developers must handle access control at the application level.

The last-mile problem: collaboration and scale

You have built this amazing analysis on your laptop. It is fast and runs in seconds. Now what? How do you share it with your team? How do you run it against the 2TB dataset in S3 without pulling it all down to your machine? This is the last-mile problem, and it is what holds many teams back from adopting DuckDB more broadly.

DuckDB in the Ecosystem

The DuckDB ecosystem solves this last-mile problem directly by extending local workflows to the cloud. A new class of serverless data warehouses is emerging, built entirely around the engine, and one specifically worked for me.

Scaling with a specialized, serverless DuckDB warehouse

MotherDuck is the leading example of this approach and the one I spent the most time with. It feels like local DuckDB but scales like a cloud warehouse.

There are several advantages to this.

Petabyte-Scale via Managed DuckLake

This removes DuckDB's traditional storage limits. With Managed DuckLake, you can query petabytes of data directly in object storage like S3 using MotherDuck's serverless compute. For me, the standout was getting that scale without leaving behind the SQL and workflow I already knew.

Hybrid Execution

Hybrid execution lets you run a single SQL query that joins a local CSV file on your laptop with a massive table in the cloud.

SELECT *
FROM read_csv_auto('local_file.csv') l
JOIN my_db.main.cloud_table c ON l.id = c.id;

The query optimizer is smart enough to run the right parts of the query in the right places, which minimizes data movement. For iterative work, that matters more than it sounds.

Isolated Compute Environments via microVMs

Anyone who has shared a cluster with a data team is no stranger to the noisy neighbor problem. MotherDuck sidesteps this by giving each user their own isolated compute environment that spins up in milliseconds. This means I didn’t have to pay for a massive shared warehouse or worry about someone else's workload affecting mine.

Zero Cluster Management

While querying petabytes of data in S3 via DuckLake requires engineering effort for partition pruning and data modeling, there are no compute clusters to manage and no warehouse suspension settings to tweak. It scales to zero instantly, removing the cluster provisioning burden from the engineering team.

Cost-Effective Compute

After the Snowflake surprise, I was really skeptical about the pricing. MotherDuck bills in 1-second increments, which means you only pay for the time your queries are actually running. No idle compute charges, no 60-second minimums.

Full DuckDB SQL Compatibility

Your local development workflow translates directly to the cloud. What you build on your laptop runs identically in production, eliminating the dev/prod mismatch. That consistency alone saves hours of environment-specific debugging.

A brief comparison to other modern OLAP engines

The comparison table earlier covers the full picture. In my experience, the trade-offs are real. BigQuery is a strong choice for GCP-native teams, but its per-TB pricing can surprise you on ad-hoc workloads. Redshift fits well in AWS ecosystems but carries operational overhead that adds up. For real-time, high-concurrency dashboards, ClickHouse can be hard to beat.

DuckDB's sweet spot is data transformation and mid-scale analytics. It is developer-centric by design, which means the speed and simplicity are built in, not bolted on.

Conclusion: Choose the right architecture for the job

This entire process has changed my approach to data architecture. There is no single right answer, and the right tool depends entirely on the workload. My heuristic is simple.

• For transactions, use Postgres.
• For local/single-node analytics (sub-terabyte to low-terabyte), use DuckDB.
• For scaling and sharing DuckDB workflows, explore a specialized, serverless warehouse like MotherDuck.
• For real-time, high-concurrency dashboards, use ClickHouse.
• For federated queries across distributed sources, use Trino/Presto.
• For unified platforms spanning ETL and ML, use Databricks.
• For petabyte-scale enterprise needs, use Snowflake (or BigQuery/Redshift), or evaluate MotherDuck's Managed DuckLake to keep DuckDB's simplicity at massive scale.

If you have felt the pain of surprise bills or hit the last-mile problem with local analytics, it is worth trying a tool that was built to solve it.

You can test this yourself with MotherDuck’s free account that comes with 10GB of storage and 10 hours of compute.

Frequently Asked Questions

Why should I choose DuckDB over Postgres for my analytical reporting layer?

Postgres is optimized for transactions, not analytics. Its row-based storage means analytical queries have to read entire rows even when they only need one column, creating I/O bottlenecks that slow queries and can impact your production database. DuckDB's columnar storage and vectorized execution are purpose-built for this workload, making it significantly faster for analytical queries on sub-terabyte data.

What is the difference between DuckDB and Snowflake, and why would I choose DuckDB for my data stack?

The primary difference between DuckDB and Snowflake is that DuckDB is an in-process embedded database, whereas Snowflake is a decoupled cloud warehouse. You should choose DuckDB for sub-terabyte workloads to eliminate the unpredictable costs of Snowflake's 60-second billing minimums. However, Snowflake remains the better fit for petabyte-scale enterprise analytics.

What are the performance advantages of using DuckDB over client-server architectures like Snowflake for datasets under 1TB?

DuckDB outperforms client-server architectures like Snowflake on datasets under 1TB by executing queries in-process and avoiding network latency. Instead of waiting for a cloud warehouse to wake up, DuckDB runs immediately on your laptop or CI/CD runner. Its vectorized engine processes data arrays simultaneously. This bypasses the workflow friction typical of monolithic environments.

Is there a cloud data warehouse that natively supports DuckDB SQL syntax so I can match my local transformation workflows?

MotherDuck natively supports DuckDB SQL syntax, so your local transformations run identically in production. Because it is a specialized, serverless cloud data warehouse, it eliminates the dev/prod mismatch. You can even use its hybrid execution to run a single query that joins a local CSV file with a massive cloud table.

Why is my Snowflake bill so high when my data isn't that big?

Snowflake charges a 60-second minimum every time a suspended warehouse resumes, so even a 200-millisecond query costs you 60 seconds of compute. Add in cloud services charges and warehouses accidentally left running, and the bill grows fast regardless of the actual data size.

What is DuckDB, and why is it suddenly popular for analytics?

DuckDB is a free, open-source analytical database that runs in-process with no server or infrastructure required. It uses columnar storage and vectorized execution to run analytical queries faster than row-based databases like Postgres, making it popular for engineers who want serious analytical capability without the overhead of a managed cloud warehouse.