Problem

The Database migration to Oracle via the Administration -> Systems Settings -> Database console fails.

The following appears in the atlassian-fisheye-DD-MM-YYYY.log

ERROR: "The database is not using Unicode. Crucible requires that the database uses a UTF8 encoding to support internalization."

Cause

The encoding configuration has been enforced in Fisheye and DB migration will not proceed unless this hard-coded check for UTF-8 has been met.
There is an improvement request open here: FE-3619 - Getting issue details... STATUS to allow users to use an encoding of their choice by suppressing these warnings.
Watch it to be notified of its progress and feel free to comment there.

Resolution

• Shutdown Fisheye and edit the <FISHEYE_INST>/config.xml file
• Add the database configuration manually as follows:

<database type="oracle">
  <connection 
    dialect="<Oracle Database dialect>" driver="<Oracle Driver Class>" 
    jdbcurl="<Oracle JDBC connection URL>" 
    password="yourdbpassword" username="yourdbuser" maxPoolSize="20" 
    minPoolSize="5" driverSource="bundled"/>
</database>

• Restart Fisheye for the  changes to take effect.