Replace Solr with Oracle Text.
Before I get down-voted: normally I would not recommend replacing existing code built with a popular, open-source program with a seldom-used, proprietary product. But if you want to use a lot of space and CPU on your database servers then Oracle Text can definitely help.
As more generic advice, the primary role of a database is not to store data. A file system can do that. Databases are built to join data. If an application is reading a large amount of data and doing ad hoc joins, those are the jobs you want to move to the database.