Query Optimization Fundamentals

Understanding EXPLAIN Plans

Index Types & Strategies

Join Optimization Strategies

Statistics and Cardinality

Parallel Query Execution

Query Store and Plan Management

Cost-Based Optimizer Internals

Tune cost parameters for SSD storage and measure impact

Analyze parallel execution plans and calculate efficiency

Identify and resolve parameter sniffing issues

Monitor buffer cache hit ratio and optimize

Use Query Store to track plan performance over time

Create plan guides for problematic queries

Compare execution plans across database versions

Optimize queries using query hints strategically

Set up alerts for plan regressions

Benchmark different parallel worker configurations

How does parallel execution work and when does it help?

What is parameter sniffing and how do you handle it?

How do you tune the cost model for your hardware?

Explain adaptive query optimization

What metrics indicate poor parallel execution efficiency?

How do you monitor and prevent plan regressions?

When would you use query hints vs fixing the root cause?

How does the buffer cache affect execution plans?

What is the difference between plan guides and query hints?

How do you optimize for both OLTP and OLAP workloads?

PostgreSQL Cost Model Documentation

SQL Server Query Store Best Practices

MySQL Optimizer Trace Analysis

Oracle Adaptive Query Optimization

Parallel Execution Internals

Parameter Sniffing Solutions

Cost-Based Optimizer Deep Dive

Production Query Performance Monitoring