Complete PostgreSQL Course for Beginners - How do SQL indexes affect INSERT and UPDATE performance?

Follow @Rebellionrider for more such questions SQL Interviewer: How do indexes affect INSERT and UPDATE performance? SQL interview questions often test performance basics. Indexes are one of the most important topics. So this question matters in real projects. Indexes improve SELECT performance. They make data search faster. They reduce full table scans. They optimize SQL queries. But indexes slow down INSERT operations. Every new row must update all indexes. More indexes mean more write work. So INSERT becomes slower in SQL. Indexes also affect UPDATE statements. If indexed columns are updated. Indexes must be rebuilt. Extra I/O is generated. So UPDATE performance reduces in SQL. If non-indexed columns are updated. Impact is smaller. But still some overhead exists. Because row locations may change. So balance is important in SQL design. Use indexes for frequent SELECT queries. Avoid unnecessary indexes. Optimize for both read and write performance.