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Database indexing is one of the most powerful optimizations — it can make queries hundreds of times faster. But like salt in food, too much indexing is harmful. Use it wisely. #database #databasedesign #indexing
🧠 Interview Tips
Indexing improves read performance but can degrade write performance.
Always index columns that are frequently filtered or joined.
Avoid indexing small tables or low-cardinality columns (like boolean flags).
Use EXPLAIN (MySQL/PostgreSQL) to check if your query is using an index.

📌 Best Practices
Index only frequently queried columns.
Prefer composite indexes for multi-column filters.
Use covering indexes to avoid table lookups.
Monitor slow queries and add indexes selectively.
Periodically rebuild or analyze indexes.