Index Only Scan vs Index Scan With Fetch

Developers should use Index Only Scan when designing queries and indexes to optimize read-heavy workloads, such as analytical queries or reporting systems meets developers should understand this concept when optimizing database queries, especially in performance-critical applications where query efficiency impacts response times. Here's our take.

Index Only Scan

Nice Pick

Developers should use Index Only Scan when designing queries and indexes to optimize read-heavy workloads, such as analytical queries or reporting systems

Pros

• It is particularly valuable in databases like PostgreSQL or MySQL for queries that filter and retrieve columns already indexed, as it minimizes disk access and speeds up response times
• Related to: database-indexing, query-optimization

Cons

• Specific tradeoffs depend on your use case

Index Scan With Fetch

Developers should understand this concept when optimizing database queries, especially in performance-critical applications where query efficiency impacts response times

Pros

• It's crucial for scenarios involving non-covering indexes, such as SELECT queries that filter on indexed columns but return additional data, helping to diagnose and improve slow queries by analyzing execution plans
• Related to: database-indexing, query-optimization

Cons

• Specific tradeoffs depend on your use case

The Verdict

Use Index Only Scan if: You want it is particularly valuable in databases like postgresql or mysql for queries that filter and retrieve columns already indexed, as it minimizes disk access and speeds up response times and can live with specific tradeoffs depend on your use case.

Use Index Scan With Fetch if: You prioritize it's crucial for scenarios involving non-covering indexes, such as select queries that filter on indexed columns but return additional data, helping to diagnose and improve slow queries by analyzing execution plans over what Index Only Scan offers.

The Bottom Line

Index Only Scan wins

Developers should use Index Only Scan when designing queries and indexes to optimize read-heavy workloads, such as analytical queries or reporting systems