Description: Index statistics are a set of data that provide information about the distribution of values within an index in a database. These statistics are crucial for the query optimizer, which is the component of the database management system responsible for determining the most efficient way to execute a query. By understanding the distribution of data, the optimizer can choose the best execution plan, resulting in faster and more efficient performance. Index statistics include information such as the number of rows, cardinality (number of unique values), the distribution of values, and their density. This information allows the optimizer to estimate the cost of different data access strategies, such as using indexes or performing full table scans. Without accurate statistics, the optimizer may make suboptimal decisions, leading to slower response times and inefficient use of system resources. Therefore, keeping index statistics up to date is essential for ensuring optimal performance in database queries, especially in environments where data changes frequently.
