In Oracle Applications, data is stored in database tables that belong to a particular application.
Each table may also contain information used to determine what conditions need to be met to access the individual records.
Incompatible reports /program can only run sequentially, the first one must terminate before the other is allowed to start.
So, it can happen that a report is pending for a long time, when it is waiting for the incompatible report to finish.
Lastly, if the domain is not provided by a program parameter and the Concurrent: Conflicts Domain profile option has not been defined the 'Standard' domain is used.
The Standard domain is the default for all requests.
You can think of a logical Defining database as a line drawn around a set of related data for which you wish to define concurrent program incompatibilities.
More on Oracle Conflict Domains A conflict domain is a set of related data stored in one or more ORACLE schemas and linked by grants and synonyms.
Do not confuse logical databases with your ORACLE database.
These conditions may consist of one or more of the following data groupings: A conflict domain is an abstract representation of the groupings used to partition your data.
There is no limit to the number of domains that can be defined, but excessive domains may hurt performance.