Answer
Indexing performance is the effect indexes have on query speed, writes, storage, and maintenance. • Useful indexes can avoid scanning every table row. • Every added index must be updated by relevant INSERT, UPDATE, and DELETE operations. • Execution plans and measured workloads should guide index choices.
💡 SQL Example
EXPLAIN SELECT * FROM employees WHERE department_id = 10;
Result
An execution plan showing a scan choice
⚡ Quick Revision
Index performance must be measured across both reads and writes.