How to Migrate from On-Premise to MySQL in PostgreSQL

How do I migrate an on-premise PostgreSQL database to MySQL?

Moves schema and data from a local PostgreSQL server to a MySQL instance using dump, transform, and load steps.

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Description

What are the essential steps?

Export the on-premise PostgreSQL schema and data, convert PostgreSQL types to MySQL-compatible ones, create target tables in MySQL, and load the transformed data. Finish by validating row counts and constraints.

Which tools work best?

Use pg_dump for extraction, pgloader or mysqldump --compatible=postgresql for type conversion, and mysql or MySQL Workbench for loading. For large ecommerce datasets, consider AWS DMS or Ora2Pg.

How do I handle incompatible data types?

Map SERIAL to AUTO_INCREMENT, BOOLEAN to TINYINT(1), BYTEA to BLOB, and arrays to join tables. Always review date/time defaults and enum values manually.

Can I keep IDs aligned?

Add the --no-owner --no-acl flags to pg_dump, load data first, then alter MySQL sequences with ALTER TABLE ... AUTO_INCREMENT = MAX(id)+1; so new inserts continue smoothly.

How do I migrate incrementally?

Create triggers in PostgreSQL to log changes to a _delta table. Replicate this delta regularly using pg_dump --data-only and apply with mysql, or switch to AWS DMS for near-real-time replication.

What post-migration checks matter?

Compare record counts per table, run spot queries (e.g., last 10 orders), and execute application integration tests. Validate constraints, indexes, and character sets to avoid silent corruption.

When should I switch applications?

After successful checks, point application connection strings to MySQL, keep the PostgreSQL instance read-only for a few days, and monitor error logs and performance dashboards.

Why How to Migrate from On-Premise to MySQL in PostgreSQL is important

How to Migrate from On-Premise to MySQL in PostgreSQL Example Usage


-- Verify migrated order totals in MySQL vs PostgreSQL
-- PostgreSQL (source)
SELECT SUM(total_amount) FROM Orders WHERE order_date >= CURRENT_DATE - INTERVAL '30 days';

-- MySQL (target)
SELECT SUM(total_amount) FROM Orders WHERE order_date >= DATE_SUB(CURDATE(), INTERVAL 30 DAY);

How to Migrate from On-Premise to MySQL in PostgreSQL Syntax


# 1. Extract PostgreSQL schema without ownership info
pg_dump -h localhost -U admin -d ecommerce \
        --schema-only --no-owner --no-acl \
        -f ecommerce_schema.sql

# 2. Extract PostgreSQL data
pg_dump -h localhost -U admin -d ecommerce \
        --data-only --column-inserts --no-owner --no-acl \
        -f ecommerce_data.sql

# 3. Transform & load with pgloader (one-liner)
pgloader \
    postgres://admin:pass@localhost/ecommerce \
    mysql://root:pass@mysql.cloud/ecommerce

# 4. Manual MySQL creation (if skipping pgloader)
mysql -u root -p -e "CREATE DATABASE ecommerce CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci;"
mysql -u root -p ecommerce < transformed_schema.sql
mysql -u root -p ecommerce < transformed_data.sql

# 5. Example type mapping snippet
after CREATE TABLE Orders (
    id INT AUTO_INCREMENT PRIMARY KEY,
    customer_id INT NOT NULL,
    order_date DATETIME,
    total_amount DECIMAL(10,2)
);

# 6. Re-sync incremental changes
pg_dump -h localhost -U admin -d ecommerce --data-only --table=_delta | mysql -u root -p ecommerce

Common Mistakes

Dumping with plain <code>pg_dump</code> default settings. This includes ownership and ACLs that MySQL cannot parse, causing import failures. Fix by adding <code>--no-owner --no-acl</code>.
Ignoring time zone defaults. PostgreSQL stores <code>timestamp with time zone</code>; MySQL’s <code>DATETIME</code> loses offset info. Convert to <code>TIMESTAMP</code> or append UTC offsets during ETL.