Every day you can learn something new, even after 20 years in the field. For some reason, I was always under the impression that within a single schema, objects must have a unique name. Apparently, this is not the case.
During OOW17 a customer ran into a wrong result issue in 220.127.116.11, which is very bad. I diagnosed this and found out that it happens because of bloom filter, so we just disabled that and it was solved. But I still opened an SR so Oracle can find and fix this bug.
When Oracle are adding a new feature to the database, they usually add a parameter to control it. Sometimes, after adding feature and the parameter, they realize that the parameter they chose for controlling the feature is not suitable. It might be confusing, or too general or something else. In these cases they change the parameter in the following version.
Starting with Oracle 12.1 we can export views as tables. This means that the export will contains a “create table” command and its data, while the original object was actually a view.
The LIKE operator is a very useful one. It is used to match strings with partial match while using the underscore (‘_’) as a single character wildcard and the percentage sign (‘%’) as multiple character wildcard.
When writing a query with order by, we can use the column position instead of its name. This order by”trick” is easy to use, but should be handled carefully as it affects the order of rows if the column list changes.
Many people are using DBMS_STATS to gather optimizer statistics. This package has many different options, and I wanted to tell you about one option for disabling automatic statistics gathering. When we need to disable the automatic statistics gathering we usually do one of the following: