Dynamic index message (OR strategy)

Using Dynamic Index.

The term dynamic index refers to a worktable of row IDs used to process some queries that use or clauses or an in (values list) clause. When the OR strategy is used, Adaptive Server builds a list of all the row IDs that match the query, sorts the list to remove duplicates, and uses the list to retrieve the rows from the table.

For a full explanation, see Performance and Tuning Guide: Optimizing and Abstract Plans.

For a query with two SARGs that match the two indexes (one on au_fname, one on au_lname), the showplan output below includes three “FROM TABLE” sections: