When should the statistics be collected?

Ans:

Here are some excellent guidelines on when to collect statistics:

·       All Non-Unique indices

·       Non-index join columns

·       The Primary Index of small tables

·       Primary Index of a Join Index

·       Secondary Indices defined on any join index

·       Join index columns that frequently appear on any additional join index columns that frequently appear in WHERE search conditions

·       Columns that frequently appear in WHERE search conditions or in the WHERE clause of joins.