Creating a Custom Extension for Distributed PostgreSQL Deployments - Workshop

Introduction

In this tutorial, we will guide you through the process of creating a custom extension for distributed PostgreSQL deployments. This workshop focuses on developing an extension that enables PostgreSQL to communicate with a public cloud environment, compiling and installing it on a single-server PostgreSQL instance, and scaling the extension by integrating it into YugabyteDB. This knowledge is valuable for database administrators and developers looking to enhance the capabilities of PostgreSQL in distributed environments.

Step 1: Develop a Simple Extension

To begin, you'll create a basic PostgreSQL extension.

1. Set Up Your Development Environment

   • Ensure you have PostgreSQL installed on your local machine.
   • Create a new directory for your extension files.

2. Create the Extension Files

   • In your extension directory, create the following files:
     • my_extension.control - This file defines the extension.
     • my_extension.sql - This file contains SQL commands for the extension.
     • my_extension.c - This file includes the C code for your extension functions.

3. Define the Control File

   • Open my_extension.control and specify the name, version, and required PostgreSQL version:

     name = 'my_extension'
     default_version = '1.0'
     compatible_version = '12'
     

4. Write SQL for the Extension

   • In my_extension.sql, create the SQL functions that your extension will provide:

     CREATE FUNCTION my_function() RETURNS void AS 'MODULE_PATHNAME', 'my_function' LANGUAGE C;
     

5. Implement the C Function

   • In my_extension.c, implement the logic for your function:

     #include "postgres.h"
     #include "fmgr.h"
     
     PG_MODULE_MAGIC;
     
     void my_function(PG_FUNCTION_ARGS) {
       // Function implementation
       PG_RETURN_VOID();
     }
     

Step 2: Compile and Install the Extension

Once the extension files are ready, you'll compile and install the extension on a single-server PostgreSQL instance.

1. Compile Your Extension

   • Use the PostgreSQL pg_config utility to configure the build environment:

     make USE_PGXS=1
     

2. Install the Extension

   • After compilation, install the extension using:

     make USE_PGXS=1 install
     

3. Load the Extension in PostgreSQL

   • Start the PostgreSQL shell and run:

     CREATE EXTENSION my_extension;
     

4. Test the Extension

   • Verify that the extension functions are available:

     SELECT my_function();
     

Step 3: Integrate with YugabyteDB

To enhance scalability, integrate your extension with YugabyteDB.

1. Set Up YugabyteDB

   • Follow the instructions on the YugabyteDB website to set up an instance.

2. Check Compatibility

   • Ensure that your extension is compatible with YugabyteDB by reviewing the documentation.

3. Deploy the Extension

   • Similar to PostgreSQL, use the Yugabyte shell to create the extension:

     CREATE EXTENSION my_extension;
     

4. Test in a Distributed Environment

   • Test your extension in a multi-node setup to ensure it operates correctly across the cluster.

Conclusion

You've now successfully created, compiled, and integrated a custom PostgreSQL extension for use in distributed environments. This extension allows for enhanced communication with public cloud services and can be scaled using YugabyteDB. As next steps, consider exploring more complex functionalities for your extension or engaging with the Yugabyte community for further support and resources.