Organizations in the present day handle huge quantities of knowledge, with a lot of it saved based mostly on preliminary use circumstances and enterprise wants. As necessities for this information evolve—whether or not for real-time reporting, superior machine studying (ML), or cross-team information sharing—the unique storage codecs and constructions usually grow to be a bottleneck. When this occurs, information groups continuously discover that datasets that labored properly for his or her unique function now require advanced transformations; customized extract, rework, and cargo (ETL) pipelines; and intensive redesign to unblock new analytical workflows. This creates a major barrier between priceless information and actionable insights.
Amazon Athena provides an answer by way of its serverless, SQL-based strategy to information transformation. With the CREATE TABLE AS SELECT (CTAS) performance in Athena, you may rework present information and create new tables within the course of, utilizing customary SQL statements to assist scale back the necessity for customized ETL pipeline growth.
This CTAS expertise now helps Amazon S3 Tables, which give built-in optimization, Apache Iceberg help, automated desk upkeep, and ACID transaction capabilities. This mixture may help organizations modernize their information infrastructure, obtain improved efficiency, and scale back operational overhead.
You need to use this strategy to remodel information from generally used tabular codecs, together with CSV, TSV, JSON, Avro, Parquet, and ORC. The ensuing tables are instantly accessible for querying throughout Athena, Amazon Redshift, Amazon EMR, and supported third-party purposes, together with Apache Spark, Trino, DuckDB, and PyIceberg.
This publish demonstrates how Athena CTAS simplifies the information transformation course of by way of a sensible instance: migrating an present Parquet dataset into S3 Tables.
Answer overview
Think about a worldwide attire ecommerce retailer processing hundreds of each day buyer evaluations throughout marketplaces. Their dataset, presently saved in Parquet format in Amazon Easy Storage Service (Amazon S3), requires updates every time prospects modify scores and evaluate content material. The enterprise wants an answer that helps ACID transactions—the power to atomically insert, replace, and delete information whereas sustaining information consistency—as a result of evaluate information adjustments continuously as prospects edit their suggestions.
Moreover, the information group faces operational challenges: guide desk upkeep duties like compaction and metadata administration, no built-in help for time journey queries to research historic adjustments, and the necessity for customized processes to deal with concurrent information modifications safely.
These necessities level to a necessity for an analytics-friendly resolution that may deal with transactional workloads whereas offering automated desk upkeep, lowering the operational overhead that presently burdens their analysts and engineers.
S3 Tables and Athena present a great resolution for these necessities. S3 Tables present storage optimized for analytics workloads, providing Iceberg help with automated desk upkeep and steady optimization. Athena is a serverless, interactive question service you should utilize to research information utilizing customary SQL with out managing infrastructure. When mixed, S3 Tables deal with the storage optimization and upkeep robotically, and Athena offers the SQL interface for information transformation and querying. This may help scale back the operational overhead of guide desk upkeep whereas offering environment friendly information administration and optimum efficiency throughout supported information processing and question engines.
Within the following sections, we present use the CTAS performance in Athena to remodel the Parquet-formatted evaluate information into S3 Tables with a single SQL assertion. We then reveal handle dynamic information utilizing INSERT, UPDATE, and DELETE operations, showcasing the ACID transaction capabilities and metadata question options in S3 Tables.
Stipulations
On this walkthrough, we can be working with artificial buyer evaluate information that we’ve made publicly out there at s3://aws-bigdata-blog/generated_synthetic_reviews/information/. To comply with alongside, you could have the next conditions:
- AWS account setup:
- An IAM consumer or position with the next permissions:
AmazonAthenaFullAccessmanaged coverage- S3 Tables permissions for creating and managing desk buckets
- S3 Tables permissions for creating and managing tables inside buckets
- Learn entry to the general public dataset location:
s3://aws-bigdata-blog/generated_synthetic_reviews/information/
You’ll create an S3 desk bucket named athena-ctas-s3table-demo as a part of this walkthrough. Make sure that this identify is accessible in your chosen AWS Area.
Arrange a database and tables in Athena
Let’s begin by making a database and supply desk to carry our Parquet information. This desk will function the information supply for our CTAS operation.
Navigate to the Athena question editor to run the next queries:
As a result of the information is partitioned by product class, you could add the partition data to the desk metadata utilizing MSCK REPAIR TABLE:
The preview question ought to return pattern evaluate information, confirming the desk is prepared for transformation:
Create a desk bucket
Desk buckets are designed to retailer tabular information and metadata as objects for analytics workloads. Comply with these steps to create a desk bucket:
- Check in to the console in your most well-liked Area and open the Amazon S3 console.
- Within the navigation pane, select Desk buckets.
- Select Create desk bucket.
- For Desk bucket identify, enter
athena-ctas-s3table-demo. - Choose Allow integration for Integration with AWS analytics companies if not already enabled.
- Depart the encryption choice to default.
- Select Create desk bucket.
Now you can see athena-ctas-s3table-demo listed below Desk buckets.
Create a namespace
Namespaces present logical group for tables inside your S3 desk bucket, facilitating scalable desk administration. On this step, we create a reviews_namespace to prepare our buyer evaluate tables. Comply with these steps to create the desk namespace:
- Within the navigation pane below Desk buckets, select your newly created bucket
athena-ctas-s3table-demo. - On the bucket particulars web page, select Create desk with Athena.
- Select Create a namespace for Namespace configuration.
- Enter
reviews_namespacefor Namespace identify. - Select Create namespace.
- Select Create desk with Athena to navigate to the Athena question editor.
It is best to now see your S3 Tables configuration robotically chosen below Knowledge, as proven within the following screenshot.

If you allow Integration with AWS analytics companies, when creating an S3 desk bucket, AWS Glue creates a brand new catalog known as s3tablescatalog in your account’s default Knowledge Catalog particular to your Area. The combination maps the S3 desk bucket sources in your account and Area on this catalog.
This configuration makes certain subsequent queries will goal your S3 Tables namespace. You’re now able to create tables utilizing the CTAS performance.
Create a brand new S3 desk utilizing the customer_reviews desk
A desk represents a structured dataset consisting of underlying desk information and associated metadata saved within the Iceberg desk format. Within the following steps, we rework the customer_reviews desk that we created earlier on the Parquet dataset into an S3 desk utilizing the Athena CTAS assertion. We partition by date utilizing the day() partition transforms from Iceberg.
Run the next CTAS question:
This question creates as S3 desk with the next optimizations:
- Parquet format – Environment friendly columnar storage for analytics
- Day-level partitioning – Makes use of Iceberg’s
day()rework onreview_datefor quick queries when filtering on dates - Filtered information – Contains solely evaluations from 2016 onwards to reveal selective transformation
You’ve got efficiently reworked your Parquet dataset to S3 Tables utilizing a single CTAS assertion.
After you create the desk, customer_reviews_s3table will seem below Tables within the Athena console. You may as well view the desk on the Amazon S3 console by selecting the choices menu (three vertical dots) subsequent to the desk identify and selecting View in S3.

Run a preview question to verify the information transformation:
Subsequent, let’s analyze month-to-month evaluate traits:
The next screenshot exhibits our output.

ACID operations on S3 Tables
Athena helps customary SQL DML operations (INSERT, UPDATE, DELETE and MERGE INTO) on S3 Tables with full ACID transaction ensures. Let’s reveal these capabilities by including historic information and performing information high quality checks.
Insert extra information into the desk utilizing INSERT
Use the next question to insert evaluate information from 2014 and 2015 that wasn’t included within the preliminary CTAS operation:
Test which years are actually current within the desk:
The next screenshot exhibits our output.

The outcomes present that you’ve got efficiently added 2014 and 2015 information. Nonetheless, you may also discover some invalid years like 2101 and 2202, which look like information high quality points within the supply dataset.
Clear invalid information utilizing DELETE
Take away the information with incorrect years utilizing the S3 Tables DELETE functionality:
Verify the invalid information have been eliminated.

Replace product classes utilizing UPDATE
Let’s reveal the UPDATE operation with a enterprise state of affairs. Think about the corporate decides to rebrand the Movies_TV product class to Entertainment_Media to raised replicate buyer preferences.
First, study the present product classes and their file counts:
It is best to see a file with product_category as Movies_TV with roughly 5,690,101 evaluations. Use the next question to replace all Movies_TV information to the brand new class identify:
Confirm the class identify change whereas confirming the file rely stays the identical:
The outcomes now present Entertainment_Media with the identical file rely (5,690,101), confirming that the UPDATE operation efficiently modified the class identify whereas preserving information integrity.
These examples reveal transactional help in S3 Tables by way of Athena. Mixed with automated desk upkeep, this helps you construct scalable, transactional information lakes extra effectively with minimal operational overhead.
Extra transformation situations utilizing CTAS
The Athena CTAS performance helps a number of transformation paths to S3 Tables. The next situations reveal how organizations can use this functionality for varied information modernization wants:
- Convert from varied information codecs – Athena can question information in a variety of codecs in addition to federated information sources, and you may convert these queryable sources to an S3 desk utilizing CTAS. For instance, to create an S3 desk from a federated information supply, use the next question:

Pathik Shah is a Sr. Analytics Architect on Amazon Athena. He joined AWS in 2015 and has been focusing within the massive information analytics house since then, serving to prospects construct scalable and sturdy options utilizing AWS Analytics companies.
Aritra Gupta is a Senior Technical Product Supervisor on the Amazon S3 group at Amazon Net Providers. He helps prospects construct and scale information lakes. Based mostly in Seattle, he likes to play chess and badminton in his spare time.