We are using Apache FOP , stored within the database to be able to call a PLSQL routine that executes FOP and transforms XML to PDF format. This has been working successfully in our current live database using Oracle 12C for a number of years.
We are now in the process of migrating to Oracle 19C and have observed that our FOP process is behaving differently in that environment. Specifically, multi page PDF reports are not being rendered successfully , with blank pages being generated and only data appearing on the last page.
A specific XML payload to render a multi page PDF works successfully when processed through the same version of FOP outside of the database , but not when invoking FOP in the database via PLSQL.
On only 2 occasions we have been able to generate the specific report invoking FOP via PLSQL, which were after database/instance restarts , but then successive attempts resulted in the 'blank pages' situation, which has led me to think this could be some Java memory issue / leak. When we execute FOP via PLSQL it never errors or generates any diagnostics to suggest there is a problem.
Has anyone seen anything similar to this?