FOR ALL ENTRIES statement tuning on Oracle database

In very weird cases you get performance issues on one system and not on the other. This can happen when running Oracle and using the FOR ALL ENTRIES statement for very large data sets, while it is fine on smaller sets.

The background is Oracle blocking factors. The full background can be read in these 2 SAP notes:

The solution is to give an Oracle hint (see note 129385 – Database hints in Open SQL) with a lower number of blocking factors.

%_HINTS ORACLE '&prefer_in_itab_opt 1&&max_in_blocking_factor 100&'

Performance issue solved…

If you migrate to HANA or different database, you need to remove or redo the hint again.

Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.