amazon rds – ORA-01403 _sometimes_ while reading a file on Oracle 18c

We just checked: it also happens in on-premise Oracle 18c, latest patchset and everything.

In Oracle PL/SQL we are opening and reading a file. The file exists, we are getting data, but then sometimes while reading, the process gets killed with an ORA-01403: no data found.

Funny thing is: we restart the exact same procedure with the exact same file and it runs flawlessly, just in 1 out of maybe 25 runs, we’re getting the error.

This problem first occured after we migrated from on-premise Oracle to Amazon RDS Oracle 18c, never before.

Is this some strange Oracle 18c memory/buffer problem? We can’t wrap our heads around this issue…