Oracle to PostgreSQL Migration: The Ultimate Oracle Database to PostgreSQL Conversion Guide

If you’re currently running an Oracle database and are considering migrating to PostgreSQL, this guide is for you. We’ll cover everything you need to know about the migration process, from planning to execution. By the end of this guide, you’ll be equipped with all the knowledge necessary to make a smooth transition from Oracle to PostgreSQL.

Why migrate from Oracle to PostgreSQL?

1. PostgreSQL offers superior performance and scalability compared to Oracle.

2. PostgreSQL offers more advanced features and capabilities than Oracle, including JSON support, geospatial data types, and more.

3. PostgreSQL is open source, while Oracle is proprietary.

4. PostgreSQL supports more modern database technologies, including ACID transactions, triggers, and views.

5. PostgreSQL has a more user-friendly user interface and better documentation.

6. PostgreSQL offers better support for modern programming languages, including Python and R.

7. PostgreSQL offers better support for NoSQL databases

8. PostgreSQL offers better support for table partitioning and indexing.

9. PostgreSQL is more secure than Oracle, with features such as SSL encryption and fine-grained access control.

10. PostgreSQL is constantly being updated with new features and bug fixes, while Oracle is stagnant.

1. PostgreSQL offers superior performance and scalability compared to Oracle.

Oracle is the most popular and largest RDBMS in the world, whereas PostgreSQL is an open-source database that has been gaining popularity since 2013. Both databases are suitable for handling large data and workloads, but PostgreSQL offers more scalability than Oracle with its frequent releases of major updates and bug fixes every three months.

Oracle offers advanced security packages as costly add-ons while PostgreSQL provides free security authentications such as Host, LDAP and PAM along with role-based access control. Additionally, Oracle requires a separate license for all data replication using its GoldenGate product while PostgreSQL supports logical as well as native streaming replication without any additional licensing costs. Furthermore, Oracle does not offer compatibility with other open source RDBMSs like PostgreSQL does making it difficult to reuse existing code or migrate database schema easily between platforms if needed later on down the line.

2. PostgreSQL offers more advanced features and capabilities than Oracle, including JSON support, geospatial data types, and more.

PostgreSQL offers a number of features and capabilities that are not available in Oracle, including:

- Scalability: You can scale PostgreSQL to millions of transactions per second, while scaling Oracle is costly.

- Updates: PostgreSQL releases major updates and bug fixes every three months, whereas Oracle versions are released every 2-4 years.

- Security: PostgreSQL offers free security authentications like Host, LDAP PAM etc., as well as role based access control - with advanced security plugins available for an additional cost in Oracle.

- Replication: Logical streaming replication is supported by Postgresql whereas you need to purchase a separate license for all data replication in Oracle with its GoldenGate add ons.

- Compatibility: Postgresql is compatible with other open source RDBMSs while BYOL licensing has to be brought into play if using on demand licensing from oracle cloud development services..

3. PostgreSQL is open source, while Oracle is proprietary.

PostgreSQL is an open source database, meaning that its extension system is supported by the general community, so thousands of plug-ins are available. In contrast, Oracle has a mostly proprietary plug-in system.

The availability of free extensions makes PostgreSQL more attractive than Oracle for companies looking to migrate their databases due to its scalability, regular updates/bug fixes, security features such as data encryption with advanced security plugins and role-based access control that are all free. Additionally the compatibility with other open source RDBMSs makes it even more desirable as a migration option from Oracle.

4. PostgreSQL supports more modern database technologies, including ACID transactions, triggers, and views.

PostgreSQL is an open-source object-relational database that is ACID-compliant, reliable, integrated with all major operating systems, and compatible with popular geospatial databases such as PostGIS. It also supports advanced features such as high availability and security licensing fees. Additionally, it offers a variety of modern database technologies such as:

* Transactional Support - transactions allow you to group multiple statements into one unit so they are all executed successfully or not at all. This ensures data consistency across multiple operations on a single data set.

* Geospatial Support - PostGIS extends support for geographic information systems (GIS) allowing users to store geographical coordinates in the database's tables using simple SQL queries.

* Streaming Data – This allows users to process massive volumes of data without having to load them into memory by streaming it directly from disk instead .

5. PostgreSQL has a more user-friendly user interface and better documentation.

PostgreSQL and Oracle both offer powerful database solutions. PostgreSQL is easier to use than Oracle due to its no-charge service, continuous support, compatibility with operating systems, scalability due to its open source characteristics and its ability to provide fast resolution and recovery.

However, Oracle offers more functionality than PostgreSQL in terms of transaction isolation (read committed/repeatable read/serializable), as well as being lighter on complex environments due to being proprietary software. Additionally, Oracle offers paid services for large scaled companies that may not be available for PostgreSQL users.

6. PostgreSQL offers better support for modern programming languages, including Python and R.

PostgreSQL supports a variety of languages better than Oracle, including:

- PL/pgSQL: The built-in procedural language of PostgresQL.

- Extensions: Allows users to create additional procedural languages as plug-ins.

- Bindings: Supports bindings for even more programming languages, such as C, C++ and Python.

7. PostgreSQL offers better support for NoSQL databases

PostgreSQL and NoSQL databases both offer different advantages. PostgreSQL is a traditional relational database with support for extensibility, localization, and various programming languages. NoSQL databases are more focused on scalability and performance, allowing for read clusters to be created with potentially unlimited nodes. [Contrast]

Oracle has strong vertical read scalability but PostgreSQL can create a virtually unlimited number of nodes in a read cluster depending on the resources available to it.

8. PostgreSQL offers better support for table partitioning and indexing.

Oracle database supports table partitioning and indexing, but it is costly to scale and update. PostgreSQL offers major updates and bug fixes every three months, as well as free security authentications such as Host, LDAP, PAM, and role-based access control. It also supports logical streaming replication which is not available in Oracle.

Oracle requires separate licenses for data replication with its GoldenGate product while PostgreSQL offers native streaming replication without any additional licensing requirements. Additionally, Oracle does not offer compatibility with other open-source RDBMSs while PostgreSQL does provide this feature at no extra cost. Finally, Oracle requires BYOL (bring your own license) when used in the cloud whereas PostgreSQL can be used without any licensing restrictions in all clouds

9. PostgreSQL is more secure than Oracle, with features such as SSL encryption and fine-grained access control.

Both PostgreSQL and Oracle offer authentication systems. PostgreSQL relies on host-based authentication, allowing for greater flexibility in choosing the appropriate method. Oracle has a built-in authentication system, which provides more convenience but may limit the range of options available.

PostgreSQL also supports extensibility, allowing users to customize their database and add features as needed. Oracle does not have this feature as it is considered proprietary technology and is not open to modification or customization by users or developers. Additionally, PostgreSQL offers localization capabilities while Oracle does not have this feature at all. Finally, PostgreSQL has better performance and scalability than Oracle due to its open source nature which allows for continuous updates from the developer community over time.

10. PostgreSQL is constantly being updated with new features and bug fixes, while Oracle is stagnant.

Oracle and PostgreSQL both offer major versions every 2-4 years and minor updates every 3 months. Oracle also offers advanced security packages as costly add-ons while PostgreSQL provides free security authentications such as Host, LDAP, PAM, and role-based access control with data encryption available through advanced security plugins.

Oracle requires a separate license for data replication with its GoldenGate product while PostgreSQL supports logical and native streaming replication without additional licensing requirements. Additionally, Oracle is compatible with other open source RDBMSs but not free of charge like PostgreSQL which has an extension system supported by the general community with thousands of plug-ins available at no cost.

What to consider when migrating from Oracle to PostgreSQL

1. Database Schema Mapping

Schema mapping is the process of analyzing the schema, data, and SQL code of an existing database in order to get an estimate of the necessary effort for a migration.

By performing schema mapping before starting a migration from Oracle to PostgreSQL, developers can plan out their strategy more effectively and reduce potential risks associated with the migration process. This includes identifying any differences between schemas or data types that may impact performance or functionality. Schema mapping also helps identify any potential issues that may arise during or after migration such as table/column names that are not compatible with PostgreSQL syntax.

2. Database Objects Mapping

Mapping database objects when migrating from Oracle to PostgreSQL helps ensure that all data is migrated correctly. It constrains certain relationships on the data that cannot be violated, verifies all possible Data integrity and Referential integrity issues before performing a migration, and allows you to manually change the data types for the entire database globally or individually for each field.

This ensures that no errors occur during or after the migration process and allows you to have complete confidence in your migrated database.

3. Database Migration Tool

The Database Migration Tool is a software application that helps users analyze objects in their app and databases, find differences between them, and export data in a migration report. This tool enables users to understand what it will take time-wise and resource-wise to complete the migration process from Oracle to PostgreSQL. Ora2pg is one example of such a tool that can be used for this purpose.

4. Database Compatibility Assessment

When migrating from Oracle to PostgreSQL, it is important to analyze the schema, data, and SQL code of the existing database in order to get an estimate of the necessary effort involved.

By performing a database compatibility assessment before starting the migration process, you can identify any issues with your current setup that may need to be addressed before moving forward. This will help ensure a smooth transition from Oracle to PostgreSQL without any complications along the way.

5. Schema Conversion

Schema conversion affects migration from Oracle to PostgreSQL because it is necessary to analyze the schema, data, and SQL code of the existing database in order to get an estimate of the effort involved.

As a result of this analysis, developers can plan for any necessary changes that need to be made in order to migrate from Oracle to PostgreSQL. This includes changing data types or adjusting table structures. Additionally, developers may need to rewrite queries or update applications so that they can work with PostSQL instead of Oracle SQL.

6. Performance Assessment

When assessing the performance of a database when migrating from Oracle to PostgreSQL, it is important to consider the size and complexity of the database, as well as any existing workloads or applications that will be using it.

In addition, it is important to evaluate whether there are any bottlenecks in terms of hardware resources or network bandwidth that could impact performance during or after migration. Additionally, you should consider whether there are any changes in data structures that may require additional resources such as CPU power or storage space. Lastly, make sure you have an understanding of how long it will take for your database to be operational after migration is complete.

7. SQL Statements and Commands

The types of SQL statements and commands available for migrating from Oracle to PostgreSQL include: CREATE SEQUENCE, CREATE FUNCTION, CREATE PROCEDURE, anonymous block statement (DO $$ [DECLARE declarations] BEGIN statements

8. Target Database Types

The target database types for migrating from Oracle to PostgreSQL are:

- Integer (INT): A whole number without a fractional part.

- Float/Float Point (FLOAT): A numeric value that represents a floating point number with a decimal point.

- Double Precision Float/Double Float Point (DOUBLE PRECISION FLOAT): A 64-bit floating point number that can store very large or very small numbers accurately.

- Char/Character String (CHAR): An alphanumeric string of fixed length which can be either single or double quoted. It cannot contain special characters such as apostrophe, comma, etc., and has no limit on its length.

- Binary String/Binary Data Type (BINARY): Used for storing binary data such as images and videos in their raw form without any encoding or decoding process involved in it.

9. Memory and Locking Control

When migrating from Oracle to PostgreSQL, it is important to consider the potential impact on CPU and memory resources due to the differences in architecture and functionality. For example, PostgreSQL does not use locking for transactions or DML operations, which may reduce CPU usage but increase the risk of data corruption if multiple SQL workloads are competing for memory resources. Additionally, as PostgreSQL does not natively support sequences or functions like Oracle does, developers will need to adjust their code accordingly when migrating.

Unlike Oracle which uses locking mechanisms for transactions and DML operations, PostgreSQL does not use locks so developers need to take extra care when writing applications that will be running concurrently with other workloads on the same instance. Furthermore since Oracle supports sequences while PostgreSQL does not natively have this feature available devs will need to adjust their code accordingly when migrating from one platform to another.

10. Conversion Report and Analysis

When analyzing a conversion report and report analysis for Oracle to PostgreSQL, it is important to consider the following:

- Objects in the app and databases: Analyze the objects in your app and databases to determine differences between them. This will help you understand what resources are needed for the migration process.

- Estimated time and resource usage: Use tools such as Ora2pg to estimate time and resource usage for the migration process.

- Implementation of tasks determined during analysis: This includes schema migration, data migration, SQL migration, Oracle equivalent functions, and application code changes that need to be implemented in order for successful conversion from Oracle to PostgreSQL

How to actually migrate data from Oracle to PostgreSQL

Step 1: Evaluate and discover

1. Analyze the schema, data, and SQL code of the existing database to get an estimate of the necessary effort.

2. Identify which workloads you want to migrate and why you want to do so.

3. Discover all possible workloads by combining tools and people who understand both your application and database stack.

4. Understand all dependencies between applications/databases in your portfolio and determine scope of migration accordingly.

5. Evaluate migration strategies based on identified workloads (e.g., manual vs automated).

6 .Assess engagement strategies with stakeholders (e .g . , developers, DBAs) related to this project so everyone is on the same page regarding goals/objectives/timelines etcetera..

7 . Recognize opportunities to improve overall processes related to this project (e g , deployment cycles).

Step 2: Schema migration

1. Assessment: Before starting the migration process, it is important to assess the current system and identify any potential issues that may occur during the migration process.

2. Schema Migration: Once you have identified any potential issues, you can start migrating your schema from Oracle to PostgreSQL using a tool such as dbDiff or pg_trgm for faster and more efficient results.

3. Functional Testing: After completing the schema migration, it is vital to test all functions of your application in order to ensure there are no errors in functionality after switching from Oracle to PostgreSQL databases.

4 Performance TestingIf you’re currently running an Oracle database and are considering migrating to PostgreSQL, this guide is for you.

We’ll cover everything you need to know about the migration process, from planning to execution.

By the end of this guide, you’ll be equipped with all the knowledge necessary to make a smooth transition from Oracle to PostgreSQL.: Performance testing should be performed before AND after migrating databases in order to measure how well both databases are performing under different load conditions . This will also help detect any bottlenecks or performance issues that may arise due to changes in hardware/software environment post-migration .

5 Data Migration : Data migration involves moving data from one database system (Oracle) into another (PostgreSQL). It is important that this step is done carefully as incorrect data transfer can result in data loss or corruption endangering business operations

Step 3: Functional testing

Functional testing can help with the migration from Oracle to PostgreSQL by allowing the application to connect to the database and perform full functional tests on the converted objects with DMLs.

This helps identify any issues with the schema conversion process and allows developers to address them before deploying it in production. It also ensures that SQL results are identical in both databases, so that there are no discrepancies between them once it goes live.

Step 4: Creating a target environment in PostgreSQL

1. Install and configure PostgreSQL on the target environment.

2. Create a database user with appropriate privileges for accessing and modifying data in the PostgreSQL database(s).

3. Set up a replication strategy between the source Oracle database(s) and the target PostgreSQL database(s).

4. Configure any necessary settings such as security, backups, logging etc., for optimal performance of the target PostgreSQL environment.

5. Load test data into the target PostgreSQL database to ensure that it can handle peak usage patterns without any issues or downtime in production environments

Step 5: Data migration

1. Assessment: Before starting the data migration process, it is important to assess the database and understand its structure, schema, and relationships. This will help determine how best to migrate your data from Oracle to PostgreSQL.

2. Schema Migration: Once you have identified all of the tables that need to be migrated and their corresponding fields, you can start migrating them one by step into PostgreSQL’s schema format (e.g., table name + “id”).

3. Functional Testing: After completing schema migration for each table, test them individually for functionality before moving onto performance testing or data migration steps in order to identify any potential issues that may arise during these processes..

4 Performance Testing : Once all tables are migrated successfully with no issues detected during functional testing phase , move onto performance testing phase where you can check if there is any degradation in performance due to database migration process . If yes then take corrective actions as needed .

5 Data Migration : Once all tests are successful , proceed with data migration phase where you will load actual production data into migrated tables using appropriate tools/processes available at your disposal .

Step 6: Performance tuning

1. Analyze the database usage patterns to determine which tables and queries should be migrated first.

2. Create a database migration plan that outlines the steps needed to migrate each table, including data types and indexes that need to be created or adjusted for optimal performance with PostgreSQL.

3. As you migrate each table, use EXPLAIN command statements and other tools such as pg_stat_statements , pg_hint_plan , and pg_visibility in PostgreSQL, to identify any potential issues with query execution time or resource utilization levels that need tuning adjustments.

4. Identify any changes in hardware requirements (such as additional RAM or CPUs) that may need to be made in order for PostgreSQL to run optimally on the new environment's hardware configuration .

5 .If necessary, create new indexes or adjust existing ones using CREATE INDEX statements in order improve query performance of frequently used queries .

Step 7: Execution and testing

1. Assessment: Gather information about the existing Oracle database and identify its key features, structures, and tables.

2. Schema Migration: Use migration tools or scripts to convert the schema from Oracle to PostgreSQL. Make sure to test each step along the way for accuracy and efficiency.

3. Functional Testing: Once the schema has been successfully migrated, test all application layer workflows against the newly migrated database to ensure there are no issues or bugs in any of them (e.g., queries).

4. Performance Testing: Perform load tests on both databases (Oracle vs PostgreSQL) using various scenarios with different volumes of data in order to measure their performance differences accurately across various loads/usage patterns (e..g OLAP vs OLTP). This will help determine whether additional optimizations need to be implemented after migrating from one database platform to another (e..g indexes).

5 Data Migration : After ensuring that all functionalities are working as expected , it's time for data migration phase which involves moving data from one platform/database structure into another one while taking care of all possible risks associated with it such as integrity & security issues etc..

Step 8: Cutover to Postgres

1. Stop writes to the Oracle database and fully catch up until the overall logical replication latency is zero.

2. Change the application's connection string to point to the new Postgres database, and resume writes to complete cutover.

3. Rearchitect applications as needed, and ensure that all code deployment best practices in the cloud are followed during this step.

4. Have a rollback infrastructure in place with clear instructions on steps to rollback along with criteria before cutover is complete; train team members well on operating on new infrastructure before cutover ends .

FAQ

What is Oracle to PostgreSQL Migration?

Oracle to PostgreSQL Migration is the process of migrating data from an Oracle database to a PostgreSQL database.

This process involves assessing the current state of the database, creating a schema for the new system, migrating existing data from Oracle to PostgreSQL, testing for functionality and performance issues, and finally migrating any remaining data. It is important to note any key differences or incompatibilities between the two systems before beginning the migration process. Additionally, it is helpful to use free data migration tools during this process in order to ensure success.

What is the ultimate Oracle Database to PostgreSQL Conversion Guide?

1. Ensure that your environment is ready for an Oracle to Postgres migration. This includes setting up the right infrastructure, choosing the right tools, and understanding any potential licensing restrictions.

2. Plan your migration by using Ora2Pg, a popular open source tool available in the Postgres community, to understand how complex each feature will be and what automation capabilities it offers (e.g., auto-detection of dependencies).

3. Perform manual modifications where necessary to ensure that your Oracle database is properly converted into PostgreSQL format (e.g., adding missing columns).

4 .Once you have completed all of these steps , you can proceed with migrating data from Oracle into Azure Database for PostgreSQL or self-managed Postgres databases via Ora2Pg or another tool of choice .

What types of databases does the guide cover?

The SQL Server Migration Guide covers the migration of databases from Oracle, SQL Server, IBM DB2, MySQL, PostgreSQL and Sybase to Sybase ASA and Informix. It also provides guidance on migrating data from Teradata to any of these supported databases.

What are the benefits of using a migration tool?

The benefits of using a migration tool to migrate from Oracle to PostgreSQL include:

1. Shortening the overall time taken to complete the task.

2. Enabling easy Oracle to PostgreSQL migration with tools like AWS SCT and DMS.

3. Minimizing work when converting oracle to PostgreSQL with SCT's ability to transform dictionaries and libraries.

4. Mitigating disaster by assessing the environment and capabilities of both databases before shifting all critical modules at once (e.g., functions).

5 .Validating the process without any additional expenditure by understanding architecture, application associated with it ,and quality assurance procedures before starting work on migration project

What types of objects can be migrated from Oracle to PostgreSQL?

Objects that can be migrated from Oracle to PostgreSQL include: tables, views, sequences, functions, procedures, triggers and indexes. Additionally, you can also migrate data from one database to another using this tool.

How do you ensure a successful migration?

1. Determine the expected results and impacts of the migration process.

2. Estimate downtime tolerance during migration to ensure there is no disruption in business processes or initiatives.

3. Analyze how the PostgreSQL database will integrate and communicate with other features and functions, as well as any operational changes that may occur due to this integration process, in order to plan for them accordingly.

4. Create a detailed migration plan that includes all steps necessary for a successful migration, such as testing environments, data transfer protocols, etcetera .

5 . Monitor progress throughout the process and adjust accordingly if needed .

What compatibility issues should be considered when migrating?

When migrating from Oracle to PostgreSQL, you should consider compatibility issues such as:

1. Performance Bugs – Some PostgreSQL data types are different from their corresponding Oracle ones, which may cause issues if not tested properly. For example, the PostgreSQL “Timestamp With Time Zone” field is actually the actual equivalent of Oracle’s “Timestamp With Local Time Zone”.

2. Packaged Applications – If you are using packaged software apps that do not certify on PostgreSQL, migration cannot be commenced without asking the vendor to move their database list to include it as supported software for use with their product.

3. Large Data Volumes – Migrating large databases can be time and resource (bandwidth) consuming if done in traditional way; however, date-based partitions make it easier to isolate and move offline specific data sets within a larger database structure..

4 .Code Migration Issues - Porting code over from Oracle to work with PostgreSQL is a big challenge since most of it can be automatically migrated using tools such as AWS Schema Conversion Tool (AWS SCT) or Ora2Pg but some has to be done manually and tested accordingly before being implemented into production environments .

What are the different steps of the migration process?

1. Plan the migration: Identify the goals of the migration, such as upgrading to a newer version or switching to a different database cluster. Gather information about your current database environment, including existing databases, tables and columns, data types, indexes and any custom scripts or processes that are used with the database.

2. Create a migration plan: Once you have gathered all of the necessary information about your current environment, create an outline for your migration plan that includes all steps needed to move from your current setup to the new one. This should include details such as how much data needs to be migrated over and how long it will take; what tools will be used for backup/restore operations; which databases need special attention during migration (such as those containing large volumes of data); etcetera .

3 . Execute Migration : Once you have created an effective plan of action in step 2 above , it is time to execute on it! Start by backing up any existing databases before beginning any migrations so that if anything goes wrong during this process , you can revert back quickly without losing too much data . Then go ahead with restoring those backups into their new destination databases (or even clusters). After that , start migrating individual

What is the cost of migrating from Oracle to PostgreSQL?

Migrating from Oracle to PostgreSQL is only about as expensive as upgrading from one Oracle major version to the next. Both databases are ANSI compliant so lots of stuff just works on either database. However, it is important to note that there are additional costs associated with using Oracle databases such as those for features like partitioning and high availability which can add up quickly. Open-source PostgreSQL is free to install and use however it may be more challenging to find resources for migrating data between two RDBMS due to heterogeneous structure/data types.

Migrating from Oracle to PostgreSQL doesn't have to be a daunting task. With the right tools and preparation, you can make the switch with minimal downtime and performance issues. This guide provides all the information you need to get started on your Oracle to PostgreSQL migration.