Скачать или смотреть Should You Include the pg_catalog Schema When Migrating Your PostgreSQL Database?

Discover whether to move the `pg_catalog` schema when transferring data to a new PostgreSQL database, and understand what it contains and how it affects your migration strategy.
---
This video is based on the question https://stackoverflow.com/q/70377948/ asked by the user 'Arie' ( https://stackoverflow.com/u/2829150/ ) and on the answer https://stackoverflow.com/a/70380903/ provided by the user 'Laurenz Albe' ( https://stackoverflow.com/u/6464308/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

Visit these links for original content and any more details, such as alternate solutions, latest updates/developments on topic, comments, revision history etc. For example, the original title of the Question was: Move or not pg_catalog schema to new database

Also, Content (except music) licensed under CC BY-SA https://meta.stackexchange.com/help/l...
The original Question post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/... ) license, and the original Answer post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/... ) license.

If anything seems off to you, please feel free to write me at vlogize [AT] gmail [DOT] com.
---
Should You Include the pg_catalog Schema When Migrating Your PostgreSQL Database?

Migrating your PostgreSQL database to a newer version can raise multiple questions and considerations, particularly when it comes to schemas. One common dilemma that developers face is whether to include the pg_catalog schema when moving to a new PostgreSQL database. Here, we will explore what the pg_catalog schema is, what it contains, and ultimately, whether you should worry about moving it during your database migration.

Understanding the pg_catalog Schema

What is pg_catalog?

The pg_catalog schema is an integral component of PostgreSQL databases. It holds the metadata that PostgreSQL uses to manage the database system. This schema provides information about various aspects, including:

Tables

Views

Indexes

Data types

Functions

Operators

In essence, it holds the structural details needed by PostgreSQL to understand and interact with your database.

Importance of pg_catalog

Why does pg_catalog matter? Its significance stems from the following factors:

It serves as the reference point for PostgreSQL's internal functioning.

It enables database management and operations, ensuring that the system knows how to access and manipulate data.

As a part of the overall system, it influences how data integrity, relationships, and dependencies are maintained.

Moving Your Database: Using pg_dump

The Role of pg_dump

When migrating a database, pg_dump is a valuable tool that can help you export data, schemas, and various other components. However, it's important to note the following:

During the export process, pg_dump does not export the pg_catalog schema directly. Instead, it exports the content implicitly through CREATE and ALTER statements.

The generated dump file will encompass all necessary components to recreate the database structure in the new environment.

What Gets Excluded?

While pg_dump is comprehensive, it does have exclusions that are worth noting:

User definitions and tablespaces

Database permissions

Should You Move the pg_catalog Schema?

Conclusion: No Need to Move

To directly answer the question: No, you do not need to move the pg_catalog schema manually. When you utilize pg_dump for transferring your database, the metadata contained within pg_catalog is included as part of the generated SQL statements. Therefore, attempting to move this schema is unnecessary and may even complicate the migration process.

Recommendations

When proceeding with your database migration, consider these points:

Ensure that you utilize the latest version of pg_dump to take advantage of any improvements in export functionality.

Test the migration in a staging environment before executing it in production to catch any potential issues early on.

Be cautious with any specific configurations, user-defined functions, or extensions that could be referenced in your new setup.

By understanding this schema and how PostgreSQL manages it during migration, you can confidently carry out your database upgrade with fewer headaches.