Problem Summary: After upgrade from Oracle 11 to Oracle 12 HVR Log-based capture fails with error "F_JT0400: Log scanning error F_JZ150F. Structure of expected type 'opcode52' at vector 0 in change 5.2 of record with SCN 0x0001.F61DF6BD has unexpected size. Expected size 32"
This error occurs because after the upgrade the Oracle REDO and archive files are still in Oracle 11 format.
Older HVR version (4.7 and down) do not recognize this.
The solution is to upgrade HVR to version 5 which will recognize and handle this situation automatically.
Alternatively you can upgrade the the Oracle redo en archive files to 12 format by running statement
alter system set compatible='126.96.36.199.0' scope=spfile;
on the Oracle database and restarting it.
Please note that this action cannot be reverted. That means you cannot downgrade your Oracle database from 12 to 11 anymore.