Updating multiple columns using forall

26 Aug

Queries that compile after the asynchronous updates have completed will benefit from using the updated statistics.

Consider using synchronous statistics when you perform operations that change the distribution of data, such as truncating a table or performing a bulk update of a large percentage of the rows.

The Query Optimizer uses these statistics to estimate the enable the Query Optimizer to create a high-quality query plan.

For example, depending on your predicates, the Query Optimizer could use cardinality estimates to choose the index seek operator instead of the more resource-intensive index scan operator, and in doing so improve query performance.

Well-designed filtered statistics can improve the query execution plan compared with full-table statistics.

For more information about the filter predicate, see CREATE STATISTICS (Transact-SQL).

This option also does not generate filtered statistics.

It applies strictly to single-column statistics for the full table.

Statistics become out-of-date after insert, update, delete, or merge operations change the data distribution in the table or indexed view.

This topic discusses statistics concepts and provides guidelines for using query optimization statistics effectively.

Statistics for query optimization are objects that contain statistical information about the distribution of values in one or more columns of a table or indexed view.

Each statistics object is created on a list of one or more table columns and includes a histogram displaying the distribution of values in the first column.

Statistics objects on multiple columns also store statistical information about the correlation of values among the columns.