Shadow system mirroring of an original system during uptime of an upgrade process

A non-transitory computer-readable storage medium storing code representing instructions that when executed are configured to cause a processor to perform a process, the code comprising code to:

• define, at a shadow system, a shadow program database having a structure defining an upgrade to a structure of an original program database on an original system, and having data defining an upgrade to data of the original program database on the original system;
• select data from the original program database as the data of the shadow program database;
• modify the selected data based on a data customization implemented in the original program database of the original system;
• define an upgraded program state of the shadow program database based on a combination of the structure of the shadow program database and the data of the shadow program database;
• identify a first portion of an original user database of the original system for upgrade;
• identify a second portion of the original user database of the original system for aliasing in the shadow system;
• define, at the shadow system, a shadow user database having a structure representing an upgrade to a structure of the first portion of the original user database;
• perform at least one first transfer of data from the first portion of the original user database into the structure of the shadow user database during an uptime of the original system;
• perform a final transfer of data from the first portion of the original user database into the structure of the shadow user database during a downtime of the original system;
• replace the first portion of the original user database with the shadow user database after the final transfer of data has been performed;
• and
• replace the original program database with the shadow program database during the downtime of the original system.

A method including executing instructions recorded on a non-transitory computer-readable storage media using at least one processor, the method comprising:

• defining, at a shadow system, a shadow program database having a structure defining an upgrade to a structure of an original program database on an original system, and having data defining an upgrade to data of the original program database on the original system;
• selecting data from the original program database as the data of the shadow program database;
• modifying the selected data based on a data customization implemented in the original program database of the original system;
• defining an upgraded program state of the shadow program database based on a combination of the structure of the shadow program database and the data of the shadow program database;
• identifying a first portion of an original user database of the original system for upgrade;
• identifying a second portion of the original user database of the original system for aliasing in the shadow system;
• defining, at the shadow system, a shadow user database having a structure representing an upgrade to a structure of the first portion of the original user database;
• performing, at the shadow system, at least one first transfer of data from the first portion of the original user database into the structure of the shadow user database during an uptime of the original system;
• performing, at the shadow system, a final transfer of data from the first portion of the original user database into the structure of the shadow user database during a downtime of the original system;
• replacing, at the shadow system, the first portion of the original user database with the shadow user database after the final transfer of data has been performed;
• and
• replacing, at the shadow system, the original program database with the shadow program database during the downtime of the original system.