Being mindful of query optimizer differences between postgresql, Oracle and Db2 luw
Presented by:
Rakesh Raghav
Rakesh Raghav is a Database Specialist with AWS Professional Services in India, helping customers with successful cloud adoption and migration journey. He is passionate about building innovative solutions to accelerate customer's database journey to cloud. He also works with customers to provide guidance and technical assistance on database and analytical projects, helping them improving value of their solutions when using AWS.
Gokul Gunasekaran is a Lead Consultant with the Professional Services team at Amazon Web Services. He works as a Database Migration Specialist to help AWS customers migrate and modernize their on-premises database workloads to AWS cloud database solutions.
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In this talk we will Discusses how each of these database systems approaches query optimization differently. It emphasizes the importance of understanding these differences for effective database performance tuning and application development. Key points typically include:
- Optimizer Strategies: Each database uses distinct algorithms and strategies for optimizing queries. PostgreSQL relies on a cost-based optimizer, while Oracle has a more sophisticated approach with features like the adaptive optimizer. Db2 LUW combines various techniques, including both cost-based and rule-based optimizations.
- Statistics: The role of statistical data in optimizing queries varies. PostgreSQL and Db2 depend heavily on accurate statistics, while Oracle can make use of more advanced techniques for gathering and maintaining these statistics.
- Execution Plans: Understanding execution plans is crucial, as they show how queries will be executed. The differences in how each system generates and displays these plans can affect performance tuning efforts.
- Hints and Controls: Each database allows for different levels of control over query execution. Oracle provides extensive hinting options, while PostgreSQL has a more limited set of directives.
- Best Practices: Will concludes with recommendations on how to approach query design and optimization based on the specific characteristics of each database engine optimizer.
We will also go through examples how different engines behaved for same query making the discussion more lively and informative
- Date:
- Duration:
- 45 min
- Room:
- Conference:
- PGConf India, 2025
- Language:
- Track:
- Database Administration
- Difficulty:
- Medium