Head of Database Migration Department, Ispirer Systems
Nowadays, many people are talking about migrating their databases to PostgreSQL. Despite the fact that Postgres is a robust RDBMS that is perfect for development of various systems from web applications to social media platforms, companies often delay migration. This is because migration can seem a daunting process.
In this article we will explore the migration from MySQL to PostgreSQL inside out, including the advantages of such migration, ways to migrate a database, and intricacies of migrating data and sql objects.
MySQL to PostgreSQL: Advantages of migration
MySQL and PostgreSQL are some of the most popular databases today. However, despite their popularity, each of them has its own strengths and weaknesses. In some cases, the most suitable database may be PostgreSQL. What exactly are the benefits of migrating from MySQL database to PostgreSQL? Let's take a closer look:
- Data integrity. PostgreSQL is an ACID-compliant database which means queries maintain data integrity, and return the same output without error. There are numerous data integrity features that ensure only validated data is stored, such as primary keys, restricting and cascading foreign keys, unique constraints, not null constraints, check constraints, and others. In comparison, MySQL doesn’t support ACID and neither does it support check constraints. Moreover, there are a host of caveats for foreign key constraints.
- Managing an extra large database. PostgreSQL doesn’t restrict the size of your database. It means that it doesn’t matter how many terabytes of data you have, PostgreSQL will fly.
- Scalability options. For PostgreSQL there are a lot of open-source tools for scaling a database, such as PGpool, Slony and others. They have a lot of options that allow to do read and write separations, load balancing, and split data levels. This means that this scalability allows the database cluster to cope with rapid growth in the number of users.
- Business logic opportunities. PostgreSQL allows you to create and modify business logic according to your needs. When business is growing, it may seem that MySQL handles the workloads. As you continue to incorporate new business logic into the database, complexity of the task naturally escalates over time. Consequently, the process of creating each new query becomes increasingly time-consuming on average. Moreover, this growth in complexity brings forth challenges that may be difficult to resolve without custom “crutches”. This is when migration from MySQL to PostgreSQL turns out to be the best choice.
- Materialized views. Unlike MySQL, PostgreSQL supports views with stored results that are fixed in time unlike regular views that are recreated every time they are called. This can significantly increase the speed of query execution.
- NoSQL support. PostgreSQL is a popular choice for NoSQL features. It natively supports a rich variety of data types, including JSON, and XML. Hstore is also one of the prominent features of PostgreSQL. It is a key-value store within database Postgres that provides an opportunity to define original data types and set up custom functions, too.
- MVCC. MVCC is one of the most important reasons businesses choose PostgreSQL. It allows different readers and writers to interact with and manage a PostgreSQL database simultaneously. This eliminates the need for a read-write lock each time someone needs to interact with the data—thus improving efficiency. MVCC achieves this through “snapshot isolation.” Snapshots represent the state of the data at a certain moment. Although the latest versions of MySQL offer MYVCC, PostgreSQL is usually the best for MVCC.
- Complex read-write operations. When you need to perform complicated read-write operations while using data that requires validation, PostgreSQL is an excellent choice. However, it might be prone to slowdowns while dealing with read-only operations, unlike MySQL.
MySQL to PostgreSQL: pgloader or Ispirer Toolkit?
Pgloader is an open-source, powerful tool designed specifically for loading data into PostgreSQL from various sources, including MySQL. It's known for its flexibility and efficiency in handling large datasets. With pgloader, users can migrate data, tables, indexes, and perform transformations during the migration process.
While both Ispirer Toolkit and pgloader offer reliable solutions to convert MySQL to PostgreSQL, Ispirer Toolkit has a range of advanced migration features. Let's delve into the details:
1. Comprehensive Migration Solution. Ispirer Toolkit provides a comprehensive migration solution that covers all aspects of the migration process, including data, schema, and SQL conversion. Unlike pgloader, which primarily focuses on data migration, Ispirer Toolkit offers automated SQL conversion capabilities, streamlining the entire migration process and reducing manual effort.
2. Automated SQL Conversion. There is a widespread belief among developers that sql migration is such a daunting task that it can only be done manually. However, the vast number of conversion rules in Ispirer Toolkit and an impressive amount of successful projects prove the opposite. One of the standout features of Ispirer Toolkit is its automated SQL conversion functionality. It intelligently converts MySQL-specific SQL statements, functions, and procedures to PostgreSQL-native equivalents. This eliminates the need for manual intervention in adjusting SQL code for compatibility, saving time and effort during the migration process.
3. Automated conversion algorithms. Ispirer Toolkit is an expert system that employs advanced conversion algorithms to ensure that the converted SQL code is optimized for performance and functionality in the PostgreSQL environment. In database migration, an expert system has a number of advantages over tools based on artificial intelligence. Find out more about the comparison of AI and expert systems in our blog. These algorithms analyze the structure and logic of the SQL code, determining optimal solutions to produce efficient and effective conversions. 
4. Customization Option. Customization is a modification of the Ispirer Toolkit core, which consists of numerous conversion rules. In general, it implies either adding new conversion rules to the tool or altering existing ones. The main goal of customization is to maximize the efficiency of automated database migration. This includes correcting errors that occurred during the test migration with Ispirer Toolkit and were highlighted in the conversion reports . It also involves decreasing the time required for the migration project.
5. Technical support. When a user makes a choice in favor of an open source solution, they are alone in the field. The Ispirer Toolkit license always implies support from the team, which can quickly help resolve any technical issues, help with setting up the tool and answer any questions. Therefore, when migrating with the help of such a tool, the user can count on timely and professional support.
Migrating data stage
Ispirer Toolkit offers advanced data type mapping and conversion capabilities to ensure that data is transferred accurately and seamlessly between source and target databases. It automatically maps data types from the source to the corresponding data types in the target database, handling differences in data type definitions, sizes, and formats.
Additionally, the toolkit provides options for customizing data type mappings and defining conversion rules to accommodate specific requirements or preferences. This ensures that the migrated data retains its integrity and consistency throughout the migration process.
Ispirer Toolkit employs efficient data transfer methods to optimize performance and minimize downtime during the migration process. It supports various data transfer techniques, including bulk data loading, parallel processing, depending on the characteristics of the source and target databases. These techniques help expedite the migration process, especially for large volumes of data, by maximizing throughput and minimizing latency.
Pgloader is an open-source database migration tool that aims to simplify the process of migrating to PostgreSQL. It can extract data from MySQL, MSSQL, Oracle, and even another PostgreSQL host. It can perform ETL transformations from one database to another under certain special circumstances. Basically, this tool is only suitable for data migration. So, it will not be able to migrate sql objects, that’s why when choosing this tool for migration, you will have to look for other tools for migrating the database schema in order to avoid wasting time manually rewriting the code.
SQL Migration stage
Migrating SQL objects is a daunting task that requires meticulous attention and expertise. Pgloader doesn’t provide opportunities for schema conversion, that’s why we are going to examine converting of sql using Ispirer Toolkit.
One of its standout features is automated schema conversion capabilities. Ispirer Toolkit excels in this aspect by automating the conversion of database schema objects, including tables, views, indexes, constraints, stored procedures, functions, and triggers.
Automated schema conversion means that the toolkit handles the translation of SQL code from MySQL dialect to PostgreSQL dialect, ensuring compatibility and preserving the functionality. This process significantly reduces the manual effort and complexity of schema conversion, allowing organizations to expedite the migration process without compromising on quality or accuracy.
Moreover, Ispirer Toolkit offers comprehensive migration reports that allow to analyze and quickly address all the issues encountered during the transition. Despite the automation provided by the toolkit, it's not uncommon for unexpected errors or discrepancies to arise, especially when migrating complex SQL codebases. A migration report helps to get a full picture of the errors occurred, as it contains error logs, warnings, and suggestions for manual intervention. By providing teams with actionable insights into the migration process, reports make it possible to address errors effectively, and ensure a smooth transition to the new database.
Ispirer Toolkit offers a great amount of conversion settings to configure the migration process and optimize the process as much as possible. Users can operate Ispirer Toolkit using tens of in-built settings or request the Ispirer team for customization.
Customization usually is a way out for optimizing migration when the database is too specific for migrating it with default settings and even decent configuration does not eliminate conversion errors. In such a case, the Ispirer team can develop a customized solution by defining custom conversion rules, mapping templates, and transformation logic to accommodate specific SQL code patterns, business rules, or preferences. Such an approach allows full automation with zero conversion errors and speeds up migration 3-4 times. You can learn the details about the customization of Ispirer Toolkit in our blog.
The final word
In conclusion, both pgloader and the Ispirer Toolkit offer robust solutions for migrating MySQL to Postgres databases, each with its own set of strengths and capabilities. Here is a brief comparison of the main features of both tools:
Pgloader stands as an open-source solution that simplifies data migration, however it doesn’t provide any schema conversion capabilities.
On the other hand, Ispirer Toolkit offers a comprehensive solution for MySQL to Postgres migration, including automated schema conversion, data transfer, error handling, and customization options. Furthermore, the toolkit's comprehensive reports and customization opportunities empower users to address migration challenges effectively and ensure a smooth transition to PostgreSQL.
Ultimately, the choice between pgloader and the Ispirer Toolkit depends on factors such as the specific needs of the organization, and the complexity of migration projects. In case you would like to try Ispirer Toolkit in action, you can download a free trial version for MySQL to PostgreSQL migration.