The Pros and Cons of ETL and ELT for Data Warehousing

Hardik Shah
4 min readMar 13


For businesses to successfully manage and analyze massive amounts of data, data warehousing is a critical procedure. In order to make wise choices, it enables businesses to store, arrange, and retrieve data from various sources. However, integrating data into a data warehouse can be a difficult and time-consuming procedure. ETL (Extract, Transform, Load) and ELT (Extract, Load, Transform) are used in this situation.

In this blog post, we’ll look at the benefits and drawbacks of ETL and ELT for data warehousing, as well as how companies can select the best data integration technique for their requirements.

The Pros of ETL for Data Warehousing

Data is extracted from different sources, transformed to meet the needs of the data warehouse, and then loaded into the warehouse using the traditional data integration technique known as ETL. The following are some advantages of using ETL for data warehousing:

  1. Data cleansing: Before being loaded into the data warehouse, data is cleaned using ETL to ensure that it is accurate, full, and consistent. This guarantees that the data centre has high-quality information that can be analysed and used to make decisions.
  2. Data transformation: ETL also enables the conversion of data from its original format to the format needed by the data warehouse. By doing this, it is made possible for the data to be consistent and simple to incorporate into the data warehouse.
  3. Real-time updates: The data repository can receive real-time updates from ETL. More recent information is made available as a result, which is beneficial in particular for sectors where change happens quickly.
  4. ETL processes are generally simpler to manage than ELT processes because they give users more control over the consistency and quality of the data.

The Pros of ELT for Data Warehousing

Data is extracted from different sources and loaded into the data warehouse before being transformed using ELT, a more recent data integration technique. Using ELT for data storage has the following advantages:

  1. Flexibility: Because ELT enables data processing at the source, it gives users more freedom when working with large amounts of data. As a result, there would be no need for a distinct transformation layer, which could shorten processing times.
  2. Scalability: ELT is more scalable than ETL because it provides for the quick and effective processing of big volumes of data.
  3. Reduced storage needs: By doing away with the necessity for a separate transformation layer, ELT can reduce storage needs. Businesses may experience significant cost savings as a consequence of this.
  4. Better for unstructured data: Since unstructured data can be loaded directly into the data warehouse before being transformed, ELT is better suited for managing unstructured data, such as social media or machine-generated data.

The Cons of ETL and ELT for Data Warehousing

Despite the fact that ETL and ELT are frequently used for data storage, they are not without flaws. We’ll examine some of the major drawbacks of these strategies in this part.

1. Complexity

Processes like ETL and ELT can be challenging, particularly when working with a lot of data from various sources. It can take a lot of time and resources to extract data from different sources, modify it to fit the target data model, and load the modified data into a data warehouse. Longer development times, higher costs, and a greater chance of errors can result from this complexity.

2. Data Quality

The risk of problems with data quality is another possible disadvantage of ETL and ELT. Errors or inconsistencies could happen as data is extracted from various sources, transformed, and put into the data warehouse. These problems may cause the data warehouse to contain inaccurate or incomplete data, which could have a detrimental effect on decision-making and analysis.

3. Scalability

Scaling ETL and ELT can be difficult, especially when working with significant amounts of data. Performance problems may arise as a result of the need for longer ETL or ELT processing times as data volume grows. These procedures might need to be scaled up with more expensive hardware or software.

4. Maintenance

ETL and ELT process maintenance can be a difficult and time-consuming job. The ETL or ELT process may need to be updated to account for changes as new data sources are added or as current sources are altered. This procedure can be difficult and time-consuming, especially for large data warehouses with numerous data sources.

5. Real-time processing

As batch processing methodologies, ETL and ELT are not intended for real-time data handling. For businesses that depend on current info for decision-making, this may be a drawback. A distinct strategy, such as event-driven architecture or stream processing, is needed for real-time data processing.


In summation, when it comes to data warehousing, both ETL and ELT have benefits and drawbacks. While ELT is a more recent strategy that makes use of cloud-based processing, ETL is a tried-and-true method that has been used for many years. The best option will depend on the particular needs and objectives of the company because both strategies have their advantages and disadvantages.

It’s crucial to take into account aspects like data intricacy, data quality, scalability, maintenance needs, and real-time processing requirements when choosing between ETL and ELT. Businesses can select the strategy that is best suited to their needs and goals by carefully weighing the advantages and disadvantages of each approach, leading to a more effective and efficient data warehousing solution.