Migration Guide from PostgreSQL to MySQL: Updated Procedures Even Beginners Can Follow
Overview
Migrating from PostgreSQL to MySQL may become necessary due to changes in system requirements or operational environments. This article provides a beginner-friendly explanation of the migration process between the latest versions of PostgreSQL and MySQL. It includes practical information on how to use specific tools and what to watch out for.
Target Audience
- Engineers and system administrators considering migration from PostgreSQL to MySQL
- Those new to database migration
- Anyone looking to learn about selecting and using migration tools
Pre-Migration Preparation
1. Version Check
Verify the versions of the source PostgreSQL and the target MySQL to ensure compatibility. Migration between the latest versions is recommended, but be aware that there may be caveats with certain version combinations. Refer to official documentation and the compatibility of migration tools.
2. Backup
Before proceeding with the migration, make sure to take a complete backup of the PostgreSQL database. This ensures data recovery in case of any issues.
pg_dump -U username -F c -b -v -f backup_file.backup database_name
3. Selecting a Migration Tool
The following tools can be used for migration:
- MySQL Workbench: A GUI-based tool that allows intuitive operation.
- pgloader: A command-line tool that enables fast data migration.
Migration Procedure Using MySQL Workbench
Step 1: Install PostgreSQL ODBC Driver
To migrate data from PostgreSQL using MySQL Workbench, you need to install the PostgreSQL ODBC driver. Download and install the appropriate version from the official site.
Step 2: Launch MySQL Workbench and Start Migration Wizard
Start MySQL Workbench, go to the “Database” menu, and select “Migrate” to launch the migration wizard.
Step 3: Configure Source Database
Enter the PostgreSQL connection information and click “Test Connection” to confirm connectivity. If successful, click “Next” to proceed.
Step 4: Configure Target Database
Enter the MySQL connection information and click “Test Connection” to confirm connectivity. If successful, click “Next” to proceed.
Step 5: Select Schemas and Objects
Choose the schemas, tables, views, and other objects to migrate. You can narrow down the scope of migration if needed.
Step 6: Execute and Verify Migration
Follow the wizard instructions to execute the data migration. After completion, verify that the data has been correctly migrated to MySQL.
Migration Procedure Using pgloader
Step 1: Install pgloader
pgloader is a command-line based migration tool. Install it with the following command:
sudo apt-get install pgloader
Step 2: Create a Migration Configuration File
Create a configuration file (e.g., my.load) and write the following content:
LOAD DATABASE
FROM postgres://username:password@hostname:port/dbname
INTO mysql://username:password@hostname:port/dbname
WITH include drop, create tables, create indexes, reset sequences,
workers = 8, concurrency = 1,
multiple readers per thread, rows per range = 50000, prefetch rows = 10000
Step 3: Execute Migration
Run the migration with the following command:
pgloader my.load
After completion, verify that the data has been correctly migrated to MySQL.
Points to Consider During Migration
- Data Type Differences: PostgreSQL and MySQL may behave differently even for identically named data types. Check data type compatibility in advance and apply conversions if necessary.
- Encoding Check: Differences in character encoding may cause garbled text. Ensure consistent encoding before and after migration.
- Recheck Indexes and Constraints: After migration, verify that indexes and constraints are properly set. Recreate them if needed.
Summary
Migration from PostgreSQL to MySQL can be performed smoothly with proper preparation and the right tools. Leverage tools like MySQL Workbench and pgloader to streamline your migration efforts. After migration, confirm data integrity and performance to ensure stable operations.
Intended Audience and Impact
This article provides valuable information for engineers and system administrators tackling database migration for the first time. By clearly outlining the steps and considerations, it helps reduce anxiety around migration and supports a smooth process. Additionally, by listing post-migration checkpoints, it contributes to stable system operation.