Query Optimization Fundamentals

Index Types & Strategies

Join Optimization Strategies

Subquery Optimization

Statistics and Cardinality

Query Rewriting Techniques

Table Partitioning Strategies

Caching and Memory Management

Run EXPLAIN ANALYZE on a slow query and identify the bottleneck

Compare estimated vs actual rows and update statistics if needed

Find sequential scans in execution plans and add appropriate indexes

Analyze join methods and determine if they're optimal for the data size

Identify expensive sort operations and add indexes to eliminate them

Read execution plans for queries with multiple joins and optimize join order

Use EXPLAIN to verify indexes are being used after creating them

Compare execution plans before and after optimization to measure improvement

Analyze a query with "Using temporary" and "Using filesort" and fix it

Practice reading execution plans in different database systems

How do you read an execution plan and identify the main bottleneck?

What is the difference between EXPLAIN and EXPLAIN ANALYZE?

What does it mean when estimated rows differ from actual rows by 100x?

Explain the difference between Index Seek, Index Scan, and Table Scan

What are the three main join methods and when is each appropriate?

How do you identify missing indexes from an execution plan?

What does "Using temporary; Using filesort" mean in MySQL?

How do you determine if a sequential scan is acceptable or needs optimization?

What metrics do you look for in an execution plan to identify performance issues?

Walk through optimizing a query based on its execution plan

PostgreSQL EXPLAIN Documentation

MySQL EXPLAIN Output Format

SQL Server Execution Plan Basics

Use The Index, Luke - Execution Plans

Execution Plan Analysis Best Practices

Understanding Query Optimizer Decisions

Reading Execution Plans Like a Pro

Database Statistics and Cardinality Estimation