NSSQL TIPS #3

Avoid sorting

Avoid sorting of large amounts of data. It takes time and has a negative influence on performance.

Sorting may be used in the following cases:

-       ORDER BY

-       GROUP BY

-       DISTINCT

-       UNION (not with UNION ALL)

-       MERGE JOIN

Avoid re-opening a cursor with a large sort in its access-path. If such a cursor is closed, e.g. due to a COMMIT, then reopening the cursor to continue processing will result in repeating of the sort. This is killing for performance. If possible open the cursor with BROWSE ACCESS outside a TMF transaction.