Optimized database migration for large systems between platforms with different endianness

A computer system for data migration from a source database system to a target database system, the computer system comprising one or more processors configured to perform operations of:

• identifying, during an uptime of a source database system, one or more increments between a back-up copy of the source database system and the source database system, wherein:
• the source database system comprises:
• one or more datafiles encoding data objects, and tablespace data encoding table and index data, and
• the back-up copy of the source database system comprises:
• the one or more datafiles encoding data objects;
• backing up, into the back-up copy and during the uptime of the source database system, user data of the source database system, the user data encoding users, and respective roles, credentials, and assignments of the users;
• restoring, in parallel and during the uptime of the source database system, the one or more datafiles from the back-up copy to a target database system, the target database system using an endian format different from the source database system;
• sequentially performing, during a downtime of the source database system,
• (i) setting the tablespace data to read only;
• (ii) recovering datafiles on the target database system in accordance with the one or more increments;
• (iii) setting the tablespace data to read and write;
• and
• subsequently activating the target database system to go live while starting to restore the user data of the source database system,
• wherein a gap exists between when the source database system enters the downtime and when the target database system is activated, and
• wherein the gap is limited to a duration of said recovering data files on the target database system in accordance with the one or more increments.