Critical differences between PostgreSQL TEXT vs VARCHAR

PostgreSQL, or Postgres, is a leading relational database management system (RDBMS). It has earned a strong reputation for its proven architecture, robust feature set, reliability, data integrity, extensibility, and vibrant open-source community to deliver performant solutions. 

However, there are some considerations that you have to take into account when using the database. 

For instance, when designing a database schema in Postgres, one thing to consider is selecting the appropriate data type for your text-based columns. It offers a variety of data types for storing textual information, with Postgres VARCHAR and TEXT being two of the most commonly used ones. 

In this article, we will discuss Postgres TEXT vs VARCHAR data type, and you will learn the key differences between them in detail. 

What are TEXT and VARCHAR Data Types? 

In Postgres, TEXT is a character data type that can store strings of any length. It is an unlimited-length string data type, which means it can store as little or as much text according to your requirements. This data type doesn’t take any argument for mentioning the length of the character. The syntax of this data type is as follows: 

your_variable TEXT

Here, the your_variable is the name of the variable you want to use in the TEXT datatype. 

On the other hand, the VARCHAR data type, short for “variable character,” is also a character data type that can store strings of varying lengths. However, unlike the TEXT, VARCHAR has a specified length limit, which you define when creating the column. The VARCHAR data type is denoted as Varchar (n), where n is the character length limit. If you don’t specify the n, it takes characters of infinite length. Here’s the syntax for the VARCHAR data type: 

your_variable VARCHAR (n)

Here, your_variable is the name of the variable you want to use in the above data type. 

Postgres TEXT Vs VARCHAR: Key Differences

Postgres TEXT Vs VARCHAR: In-Depth Comparision

Here is a detailed comparison between TEXT and VARCHAR data types: 

Use Cases

You can use TEXT data types for many things. Some use cases are mentioned below: 

• Storing Huge Texts: TEXT is a versatile data type ideal for storing large and variable-length text, such as comments, articles, or blog posts. ‍
• Content Heavy Fields: This data type is preferred for a field containing lengthy and unpredictable content, as it has no predefined length restrictions. 

VARCHAR has the following key use cases: 

• Specified Length Fields: If you have a specified limit on the length of your data, VARCHAR is a good choice as it gives you an option to set a limit to a field. This can include storing addresses, usernames, or emails.‍
• Data Validation: When validating the data, the VARCHAR data type’s length limit can help you prevent data inconsistencies and potential issues from excessively long input. 

Indexing

In Postgres, you can create indexes on TEXT and VARCHAR columns, improving query performance, especially for filtering and querying operations. It enables faster retrieval and query of data based on the indexed column’s values. So, both data types have similar performance benefits when searching and filtering specific data.

Storage

The TEXT variable uses a variable-length storage that stores the actual data plus a few bytes of overhead. This makes it ideal for columns with variable-length content, such as descriptions or feedback. However, TEXT is also inefficient in memory storage as there is no limit to the type it can store.

Contrarily, the VARCHAR data type can be more storage-efficient because you know the maximum defined limit of your data. It allocates storage based on the declared limit and reduces space wastage compared to TEXT.

While the storage efficiency in Postgres TEXT and VARCHAR differ, they both store values as with each value preceded by a 4-byte length indicator. 

Performance

TEXT values may lead to slightly slower performance than VARCHAR because of its variable length nature. However, TEXT has a slight advantage if you want to perform operations like substring extraction or string concatenation, as it doesn’t require length checks. 

While VARCHAR is behind TEXT in complex text operations, it can be a good choice to enforce data integrity and prevent accidental storing of long strings. TEXT allows Postgres to allocate storage space more efficiently based on predefined limits. So, VARCHAR is more efficient in situations where the predicted performance is paramount. 

Example of TEXT vs VARCHAR in Postgres

Below is an example in which both data types are used in the Postgres database to understand the difference between them easily: 

• Firstly, let’s create a table to test TEXT. Below is a sample code:

CREATE TABLE TYPE_example (A TEXT,B VARCHAR(10),)

Replace TYPE_example with your desired table name, where A is a TEXT variable, and B is a VARCHAR variable with a length of 10. 

• Next, you must insert some values via the INSERT INTO command.

INSERT INTO TYPE_example (A, B) VALUES (‘This is a text type’, ‘this is a varchar type’)

After running the command above, you’ll see the VARCHAR column or B variable will throw an error because it exceeded the character limit. 

• Let’s try inserting the values one more time:

INSERT INTO TYPE_example (A, B) VALUES (‘This is a text type’, ‘VARCHAR’)

In this attempt, the record will be inserted into the TYPE_example. This is because the B variable is under the specified character limit, and the A variable doesn’t have any specified limit. 

NOTE: VARCHAR can accept unlimited characters if you didn’t specify the length parameter or ‘n’ within the VARCHAR data type. 

Best Practices For Using TEXT and VARCHAR in Postgres

Here are some of the best practices you can consider to use both data types efficiently in the Postgres database:

Consistency

Since TEXT and VARCHAR have different features, you might want to use them interchangeably according to specific use cases. However, choosing one over the other gives you consistency, which is better maintainability. Therefore, you should stick with one data type and consistently apply it throughout the schema. 

Optimize Storage

You should not only rely on data types for storage optimization of your data. If you have huge datasets, consider storage optimization techniques for whatever data type you use, TEXT or VARCHAR. This can include processes like partitioning or compression to improve performance and manageability. 

Monitor Performance

Continuously monitor memory usage and the performance of query execution using built-in tools and Postgres query execution statistics. This will allow you to take action on updating data types according to your evolving datasets. 

Streamline Data Integration With Airbyte

TEXT or VARCHAR, using any data type in Postgres, requires data, and with data spread out in so many places, it can be challenging to centralize it. That’s where tools like Airbyte come into play. 

Airbyte is one of the leading tools for integrating data from multiple sources into Postgres. It has the largest catalog of pre-built connectors, with over 350+ pre-built connectors that allow you to connect to specific connectors of your choice. Airbyte also has a specialized Postgres connector that comes with many features, including: 

• Data replication from tables, views, and materialized views. 
• Multiple methods for keeping the data fresh, including replication using the xmin system column and change data capture. 
• All the available sync modes provide flexibility in delivering data to any other destination.
• Reliable replication at any table with chunking of database reads and checkpointing.  

Beyond connectors, the tool offers many features, such as an easy-to-use interface, orchestration capabilities, and robust security. 

Key features of Airbyte include: 

• Custom Connectors: In its extensive connector library, if you still don’t find connectors of your choice, you can build custom ones using its connector development kit within minutes. 
• Scheduling and Monitoring: Airbyte offers robust monitoring and scheduling capabilities for data replication, allowing you to choose real-time or batch updates. You can easily schedule data pipeline tasks and track performance using its intuitive user interface.

Conclusion

In Postgres, TEXT and VARCHAR data types can store the character data. However, there are certain specific differences that you have read above. You have learned almost every difference between TEXT vs VARCHAR in Postgres, from use cases, storage requirements, performances, and indexing. By following the differences carefully, you can choose what data type fits your requirements best and use it accordingly.

However, if you want to integrate data into Postgres, you should use Airbyte. It follows the modern approach of ELT and automates the whole data integration process. Over 40,000+ engineers use Airbyte for data replication. Join the community and Sign up for Airbyte today!