Prompted by a (not really that) recent discussion on the OTN
forum I've decided to publish this note.Sometimes you have the task of comparing column values and handling the NULL value cases correctly makes this rather cumbersome for columns that are allowed to be NULL.The "official" SQL way of comparing two column values and to find out whether they are equal or not - under the assumption that having NULL in both columns (more...)
A new version 4.23 of the XPLAN_ASH utility is available for download.As usual the latest version can be downloaded here.
This version comes only with minor changes, see the change log below.
Here are the notes from the change log:
- Finally corrected the very old and wrong description of "wait times" in the script comments, where it was talking about "in-flight" wait events but that is not correct. ASH performs a "fix-up" (more...)
Quite often you can get into trouble with Oracle when you start combining different features.In this case of one my clients it is the combination of user-defined PL/SQL functions
that can raise exceptions
(think of currency conversion and a non-existent currency code gets passed into the function), DML error logging
and attempting to improve performance by wrapping the PL/SQL function call into a scalar subquery
to benefit from the built-in scalar subquery caching feature (more...)