Amazon Redshift ELT: Getting Started & Best Practices

CEO, Portable

What is Amazon Redshift?

Amazon Redshift is an AWS-managed data warehousing service that has been designed for heavy-duty analytics. It enables users to store and process large amounts of data, which is also referred to as big data.

It utilizes MPP (Massively Parallel Processing) to break down this data into parts and disperse it across multiple nodes. This allows for quick processing and evaluation of data. This way, companies can concentrate on their data analysis instead of managing the underlying infrastructure.

Understanding the Basics of Amazon Redshift


Amazon Redshift is structured around a clustered system with one leader node and multiple compute nodes. The leader node manages client interactions and oversees the query execution, while the compute nodes execute the data in parallel.

Data Storage Mechanism

To maximize speed and optimize compression, Amazon Redshift stores data in columns instead of rows and accommodates different formats of information from structured to unstructured.

The Data Loading Process

Amazon Redshift enables you to import data from a range of locations such as Amazon S3, Amazon DynamoDB, and other databases. The COPY command is available for parallel loading.

You can also choose to use Redshift Spectrum to query data stored in S3 without having to transfer it into Redshift. Redshift also provides users with the ability to configure their clusters to meet their specific workload requirements, such as compute power and storage capacity.

The Querying Process

Amazon Redshift can be used to execute SQL queries, including more intricate analytical ones, and offers a variety of analytical functions and data types. To enhance query performance, it has a query optimizer as well as materialized views which are capable of reducing the time taken to complete the query.

Security Features

Amazon Redshift offers a wide variety of safety features. Some of them are encryption when inactive and during transmission, compatibility with VPCs, and integration with AWS IAM. Moreover, you can use Redshift's audit and surveillance capabilities to keep tabs on database functions and recognize any security problems that may arise.

What is ELT and How Does it Work?

ELT stands for Extract, Load, Transform. It is a data handling procedure that includes taking out information from various sources, inserting it into a data repository, and then altering it to the desired structure for examination.

ELT is different from ETL. In the ETL process for data warehousing, the data is changed before being inserted into the data warehouse. In contrast, the ELT process loads the information first and then reformulates it within the data warehouse.

When you use Amazon Redshift for ELT, you can see the following stages.

  • Extraction: Data is taken from different places, including on-site databases, cloud storage, and streaming data sources.

  • Loading: The acquired information is imported into Amazon Redshift with techniques like the COPY command, Amazon Kinesis Data Firehose, or Amazon Redshift Spectrum.

  • Transformation: After the data is brought into Amazon Redshift, transformations are done using SQL operations such as aggregations, merges, and filters.

ELT is favored in data processing due to its enhanced adaptability and expandability. By utilizing ELT, businesses can upload raw information into a data warehouse and change it on the go, without needing extra data processing programs or systems. 

Amazon Redshift ELT functions by allowing customers to extract information from multiple sources like Amazon S3, Amazon DynamoDB, or other relational databases and bring it into Redshift. Once the data is loaded, users can use Redshift's SQL-based query language to modify the data into the desired structure for examination.

Benefits of Using Amazon Redshift ELT

Data management is a key element of any contemporary firm, and selecting the ideal method to manage your data is crucial. With businesses producing increasing volumes of data, it is becoming increasingly necessary to discover cost-effective and efficient solutions for dealing with this information.

Amazon Redshift ELT presents several advantages that can assist organizations in achieving their data processing objectives in an economical manner. Some of them are mentioned below.


Amazon Redshift can be scaled to accommodate the increasing demand for data processing. ELT simplifies the process of scaling up by loading raw data first and then transforming it as needed.


ELT is an advantageous approach to data management in terms of its adaptability. Redshift ELT provides users with a variety of connectors that enable them to integrate their data from various sources, including data lakes and data pipelines. This gives you the power to easily deal with information from diverse sources and in distinct formats.


Moreover, ELT can help minimize expenses related to data handling since its raw format eliminates the requirement for costly ETL tools. This can result in savings on licensing fees as well as a decrease in overall costs for data processing.


ELT can be a more expeditious process than ETL, as it does away with the requirement to transform data prior to loading it into Redshift, which allows for a faster loading time and quicker analysis.


Redshift ELT can automate the process of getting data into a data warehouse by carrying out the steps of ingesting, transforming, and loading automatically, leading to a decrease in user effort and time investment. Learn more about this in our article about data warehouse automation.

Real-Time Data Processing

ELT allows for the processing of data in an instantaneous fashion. This permits decisions to be taken based on the most recent information available. It can be particularly beneficial in fields like finance or e-commerce that rely on current data.

Key Features of Amazon Redshift ELT

Amazon Redshift ELT provides several key features that enable businesses to manage and analyze their data more effectively, including:

  • Data sources: Redshift ELT supports a variety of data sources, including S3, MySQL, SQL Server, and more.

  • Ingestion: Redshift ELT can easily ingest data from various sources using its copy command or API.

  • Transformation: Redshift ELT enables users to transform their data using SQL queries, stored procedures, or Python scripts.

  • Aggregation: Redshift ELT provides users with the ability to aggregate their data using SQL queries, which enables them to analyze their data more effectively.

  • Templates: Redshift ELT provides users with a variety of templates that enable them to quickly and easily create data transformation workflows.

  • Real-time: Redshift ELT enables users to process and analyze their data in real-time, which provides businesses with valuable insights into their operations.

  • Redshift Spectrum: Redshift Spectrum enables users to query their data in S3 directly. This provides businesses with a cost-effective way to store and analyze large amounts of data using Amazon Redshift data.

Getting Started with Amazon Redshift ELT

To get started with Amazon Redshift ELT, businesses need to follow several steps, including:

  1. Preparing data for Amazon Redshift ELT

  2. Loading data into Amazon Redshift

  3. Transforming data with Amazon Redshift ELT

Preparing Data for Amazon Redshift ELT

In order to use Amazon Redshift for ELT, it is essential to go through multiple steps so the data is ready and can be effectively converted for the warehouse. It is essential to comprehend the difference between ELT and ETL.

Prior to importing data into Redshift, it is necessary to guarantee that the data is accurately shaped and organized. This requires determining the sources of data and building a data pipeline that can take in and handle information immediately or in batches. This pipeline can include data from various sources such as data lakes or databases like MySQL or SQL Server.

Once data is ingested, it must be transformed into a format that is compatible with Redshift. This includes aggregating data, cleaning and filtering data, and configuring Redshift to handle large datasets using MPP. Redshift Spectrum can also be used to query data stored in Amazon S3 directly from Redshift.

When preparing data for Amazon Redshift ELT, it is important to keep in mind specific use cases, such as business intelligence or machine learning, and configure Redshift accordingly. This may involve creating staging tables or using stored procedures for more complex data transformations.

AWS Glue can also be used to automate the ETL process and extract metadata about the data, while IAM can be used to manage access to Redshift data.

Loading Data into Amazon Redshift

Loading data into Amazon Redshift is a critical part of the ETL process. Before loading data, it is important to prepare the data for the Redshift environment

When working with Redshift, performance must be taken into account. This system is designed to handle large amounts of data by using MPP, which spreads the data across nodes and performs queries simultaneously. To make sure that performance is optimal, it's important to comprehend the way in which the data is spread out and use COPY for loading data in a parallel fashion.

Another consideration when loading data into Redshift is data integrity. Verifying that the data being uploaded is accurate and complete is essential. This can be done through data validation methods, such as computing checksums or comparing information from various sources.

To load data into Redshift, there are several options available. You cna load data through Amazon S3, AWS Glue, or through direct database connections. Additionally, Redshift provides connectors for common data sources such as MySQL and SQL Server.

Transforming Data with Amazon Redshift ELT

Using Amazon Redshift ELT for data transformation provides a significant advantage as it utilizes the massive parallel processing capacity of an Amazon Redshift cluster to rapidly process complex transformations on big datasets. This can dramatically shorten the time needed to transform and upload data into your data warehouse.

Amazon Redshift ELT can be employed to modify data by writing SQL queries. These queries enable you to run the same transformations that are used in ETL but with the bonus of being able to execute them directly on the Amazon Redshift cluster.

Another useful feature of Amazon Redshift ELT is the ability to streamline the conversion process using stored procedures and templates. Stored procedures are pre-written SQL scripts that can be reused across multiple transformations, while templates provide a starting point for creating new transformations by including commonly used SQL code and best practices.

Best Practices for Using Amazon Redshift ELT

To get the most out of Amazon Redshift ELT, businesses should follow several best practices.

Use columnar storage  - Storing data in a columnar format enables faster query processing times and better compression ratios.

Use Redshift Spectrum for budget-friendly data storage - By leveraging Redshift Spectrum, users can easily query data that is stored on S3, which makes it an economical solution when dealing with large datasets. 

Optimize Data Processing - To optimize performance, users should create efficient SQL queries and reduce the amount of data being transferred between nodes.

Use IAM roles for security - Users should use AWS Identity and Access Management roles to manage access to Redshift ELT resources.

Monitor performance - To ensure optimal performance, users should monitor the performance of their Redshift ELT clusters and adjust their configurations as necessary.

By following these best practices, you can ensure that you're getting the most out of Amazon Redshift ELT and maximizing the value of your data warehouse.

Common Pitfalls Users Should Be Aware of and Avoid When Using AWS Redshift

Amazon Redshift has many advantages, but users should be conscious of the potential drawbacks and try to prevent them. Let's have a look at some common pitfalls.

Data Quality Issues

It is critical to ensure that the data remains of high quality throughout the Extract-Load-Transform process. Should the original raw data have any issues, such as incomplete information, duplicates, or inconsistencies, these could be carried into the transformed version and ultimately result in erroneous conclusions from the analysis.

Inefficient Transformations

Transformation processes can be time-consuming and have a negative impact on the ELT flow if they are not optimized. To improve efficiency, one should utilize effective SQL commands, index tables suitably, and reduce the usage of temporary tables.

Insufficient oversight

Without adequate oversight, ELT procedures can result in data being kept in separate databases that are not able to be accessed by other parts of the company. Establishing governance policies is essential to making sure data is stored and handled uniformly throughout the organization.

Loading Redshift clusters excessively

ELT procedures can strain Redshift clusters significantly, particularly when the amount of data being handled is considerable. It is essential to keep an eye on cluster capability and adjust cluster parameters as required to prevent overwhelming the clusters.

Troubleshooting Common Issues with Amazon Redshift

Amazon Redshift is a powerful tool for integrating and processing large amounts of data from various sources, such as cloud data services, Microsoft applications, and BigQuery. However, as with any data integration process, there are often common issues that can arise during the use of Amazon Redshift ELT.

Schema mismatches

It is imperative to examine the schema of the data being loaded into Redshift. You need to confirm that it matches the schema of the intended Redshift table in order to diagnose any possible issues with loading data.

Slow Data Load Times

When dealing with a large number of data or advanced data transformations, it is essential to optimize the Redshift cluster for better performance by altering the node type or distribution style. It may also be helpful to use staging tables to preprocess and transform the data before loading it into Redshift.

Additional Challenges

When using Amazon Redshift ELT for specific use cases, such as business intelligence or machine learning, there may be additional challenges to overcome.

For example, integrating data from Snowflake or other cloud data services may require additional configuration or authentication steps. Additionally, using Lambda functions or other serverless technologies may require specific settings or permissions to work properly with Redshift. 

Keep in mind the role of metadata in troubleshooting Amazon Redshift ELT. Metadata provides valuable information about the data being loaded and can help identify issues with the data or the loading process. By utilizing metadata and monitoring tools, such as AWS Glue, it's possible to quickly identify and resolve common issues with Amazon Redshift.

Using Portable with Amazon Redshift

Portable is an ETL tool that allows for a smooth connection between different applications and Amazon Redshift. This cloud-based data integration platform makes it simple for businesses to transfer data from diverse sources to their Amazon Redshift database. Portable support long-tail connectors which are normally disregarded by other ETL tools. This makes it a perfect pick for data teams who wants to work with a broad variety of applications.

One of Portable's standout features is its vast array of pre-built connectors. With over 500+ connectors available, Portable makes it easy to connect to popular applications like Salesforce and HubSpot. The company also creates new connectors within days or even hours, at no extra cost, making it a great choice for businesses looking to connect to newly released applications. The Portable team handles maintenance, alerting, and reporting, ensuring that data pipelines are always up-to-date and running smoothly.

Portable offers a free plan that allows for manual data workflows with no limits on volume, connectors, or destinations. For businesses requiring automated data synchronization, the cost is only $200 per month. This makes it a cost-effective option for small to medium-sized businesses. For larger enterprises with more advanced requirements, Portable offers custom pricing and SLAs.

Overall, Portable is best suited for data teams who want to spend their time analyzing data rather than processing it. With its vast array of pre-built connectors and ongoing maintenance and support, Portable makes it easy to integrate data from a wide range of sources with Amazon Redshift.