AWS Athena is a powerful and affordable query service for data stored in AWS S3.

AWS is one of the leading cloud providers in the world. It offers a wide range of services for cloud storage and computational needs. AWS S3 is one of the most popular services on the AWS platform. It is among the most affordable cloud storage choices and provides data with unmatched durability and availability.

With its numerous capabilities and seemingly endless capacity, S3 buckets may hold terabytes of data. Analyzing such data would be extremely challenging if we had to open each file and manually browse through petabytes. This is where Amazon Web Services' Athena Service comes in.

Simply put, AWS Athena is used as a data analysis service, with SQL queries used to access the data stored in the S3 bucket. So, assuming you grasp the fundamentals of SQL, you may begin analyzing S3 data with AWS Athena.

Let us explain this with a brief example. Assume you've set up one of your buckets to serve as the access log bucket for all of your balancers across numerous business accounts. How would you query years of log data to extract essential, meaningful insights? AWS Athena is the solution.

Features of AWS Athena

• SQL-based Tool: AWS Athena is a very simple-to-use, SQL-based tool. Simply point Athena to one of your buckets, define your data's schema, and then start using the SQL queries in your bucket.

• Serverless: You can run AWS Athena without maintaining an infrastructure. Athena is serverless and designed to use countless computing resources automatically based on your needs.

  Fast and Optimized: Athena has been tuned to utilize the fewest resources possible to return your query results quickly. It works well for both simple and complex analysis of S3 data.

• Cost-Effective: Athena is a pay-per-use service. This means there is no initial fee for using AWS Athena; you just pay for queries executed in the Athena Service.

• Durability and Availability of the Data: Because Athena relies on the data in your S3 buckets, you can be confident that it is both available and durable.

• Support: Athena supports different file formats such as CSV, JSON, Avro, ORC, and more.

  Security: Athena utilizes security features like IAM, bucket policies, and ACLs, which make it highly secure.

• Athena Backend: Athena's backend is built on the open-source Presto platform. Presto is a distributed SQL engine for querying and analyzing big data workloads.

Pricing and Optimization of AWS Athena

When utilizing AWS Athena, you will be charged $5 per terabyte scanned. This price may vary slightly among AWS regions.

• Efficient Queries: If you're familiar with SQL, you will know there can be multiple ways to extract certain results from data using SQL. To optimize Athena, utilize efficient queries that will run in less time.

• Data Transformation: To optimize your searches further, you can compress, partition, or transform your data to a smaller dataset, reducing query execution time. Data transformation can improve your query by up to 90%.

  Joining Virtual Tables: Joining tables is an important SQL functionality. While it may appear to be a simple operation, it can actually be quite complex. Larger tables should be placed on the left and smaller tables on the right.

Difference Between AWS Athena and Redshift Spectrum

Redshift Spectrum is another service that allows you to conduct queries against AWS S3 buckets. What is the difference between Redshift Spectrum and Athena? Both are serverless, can run complicated queries on S3, and cost 5% per terabyte of data handled.

Performance

AWS Athena takes advantage of the computational resources that AWS supplies. In contrast, the Redshift spectrum takes advantage of resources allocated based on the size of the Redshift cluster. This gives you more control over the resources utilized by the Redshift Spectrum service, and if you need more performance, you can always expand the size of your Redshift cluster.

Loading the Data for Processing

Both services employ virtual tables to conduct SQL queries against your data. The Glue Data Catalog is used to maintain schema while creating virtual tables. Athena may use data straight from the Glue Data Catalog schema, whereas Redshift Spectrum requires you to configure extra tables from the Glue Data Catalog schema.

These are the primary distinctions between the two services, so choose between Redshift Spectrum and Athena. You should utilize Redshift Spectrum to query data in S3 alongside data stored in the Redshift data warehouse or if you are ready to pay more to boost query performance in S3. Athena can be beneficial when all your data is stored in S3 buckets.

Difference Between AWS Athena and S3 Select

S3 Select is another serverless service from AWS that allows you to query data in S3 using SQL. The key distinction between S3 Select and Athena is that S3 Select only supports SQL SELECT queries, but Athena supports all SQL queries. Another limitation of S3 select is that you can only use the SELECT operation on one object at a time.

So, if you simply need to pull a subset of data from an S3 object, utilize S3 Select. It would help if you utilized AWS Athena for complicated searches and operations such as JOIN and to analyze data from an entire S3 bucket.

Advantages of Using AWS Athena

• Athena eliminates the need to create a complex and costly data analysis tool for your dataset.
• Athena is a serverless service, so it's simple to use and does not require infrastructure maintenance.
• AWS has optimized Athena so that you can obtain query results in seconds after conducting the Athena query.
• Because Athena is serverless, you are not required to pay for its services. You just pay for the queries you decide to conduct. Even if you cancel a query, you will be charged only for the data processed, not the entire query.
• Athena can easily interface with other AWS services. One of the most essential and useful connectors for AWS Athena is the AWS Glue service. AWS Glue is an ETL tool that converts data into a more efficient and understandable format, which can then be analyzed with AWS Athena.
• Athena allows you to perform many queries simultaneously.

Limitations of AWS Athena

• A virtual AWS Athena table's row size should not exceed 32 megabytes. This restriction can be expanded to 100 Megabytes in very restricted instances for CSV and JSON files, although it is strongly advised to keep the row size to 32 Megabytes to avoid unnecessary problems.
• The Athena Service treats files with names that begin with an underscore (_) or dot (.) as hidden. This can be used as an option to avoid processing undesirable files.
• Athena can not process data from S3 Glacier or S3 Glacier Deep Archives. These storage classes are only used for data archiving and have retrieval times ranging from minutes to hours. Therefore, it is understandable if AWS Athena can not access their data.
• Athena does not support stored procedures.
• Athena Version 1 does not support parameterized queries. This is supported in Athena version 2.
• Additionally, it does not support the statements MERGE, UPDATE, CREATE TABLE LIKE, DESCRIBE INPUT, and DESCRIBE OUTPUT.

Conclusion

This blog examined AWS Athena, a data analysis tool, its features, advantages, and limits. Athena is a highly effective tool for processing and analyzing data in S3 buckets. Even the service's limits are relatively straightforward and can be worked around if necessary.