What is ELT? Extract, Load, Transform

Benefits of ELT: When should I use ELT?

Just like ETL, ELT is best when it comes to the following use cases:

When real-time and instant access is non-negotiable

ELT works best for real-time analysis since the data is received directly from the source and loaded immediately into the storage. This way, organizations can instantly access the data and push it for various business intelligence reports for real-time data processing and reporting.

Real-time data processing is required

For some analytics projects, real-time data processing and analytics are necessary. ELT is the way to go for these options because of its low latency, ability to handle large volumes of data, and various data formats.

Flexibility in data transformation

Since transformation occurs after loading into the database, you can transform it based on the use case requirement. This removes the required upfront transformation, as transformation does not need to be fully defined as data extraction.

When scalability, performance, and speed are of top priority

Most ELT technologies leverage parallel data transformation and distributed architectures like Hadoop, thus making it a scalable data integration process. Also, since the ELT process delays transformations till after loading, latency is reduced, and data is processed faster.

Dealing with Big Data volume

ELT data integration process favors big data because the raw data is directly loaded into the warehouse. Thus, it is a more simplified and efficient process.

Why the sudden shift from ETL to ELT?

Some decades ago, developers used ETL for processing and integrating with data sources. However, since the emergence of cloud computing technologies like DataBricks, Confluent, and Snowflake, there has been a shift to ELT. This shift has been due to all of the benefits of ELT:

• Reduced costs

• Ability to scale

• Data volume

• Flexibility in the transformation process

• Diverse data format

But will ELT replace ETL? The decision between ETL and ELT depends more on your use case and business requirements. For instance, cloud-native projects may opt for ELT because it is more cost effective. However, ETL will be more suitable for projects with predefined complex transformation logic.

Choosing Your Data Integration Method

While ELT has gained popularity with the rise of cloud-based data storage, there are situations where ETL may be the better choice. The ETL process ensures consistency, quality, data security, and performance optimization because your data is transformed and encrypted before it is loaded into the target environment.

Thus, if you have primary legacy infrastructure or monolithic setup where batch processing is adequate, then keep it simple and stick with ETL because it is often simpler and more reliable. Why? Because the data is transformed before loading and this is ideal for structured data environments.

Likewise, if you’re dealing with a massive amount of real-time data streams, have distributed systems, or need to leverage stream processing or analytics, then a real-time ETL pipeline may be the way to go. This will allow data to be brought in quickly as soon as the transformation is ready.

However, you should consider ELT when your transformation process can’t keep up with all the source data coming in.

While ELT allows for rapid data loading, especially in a cloud data warehouse, it is always best to pick a data integration method that aligns best with your goals and technical requirements. Thus a “Shift Left” back to an ETL model might offer you greater control and flexibility, especially in complex data environments.

How Confluent Can Help

By integrating historical and real-time data into a central source of truth, Confluent makes it easy to build an entirely new category of modern, event-driven applications. Leverage 100+ pre-built data connectors, gain a universal data pipeline, and future-proof your architecture to unlock powerful new use cases on enterprise scale with zero ops burden.

Learn more about how Confluent can help transform your business in minutes.