Managing Write Accesses During Database Upgrade Procedure

摘要

As part of an upgrade procedure transitioning from a source system to a target system, table entries used by both the source system and the target system can be selectively locked on a row-by-row basis using a lock table and one or more select triggers. Related apparatus, systems, techniques and articles are also described.

主权项

1. A method comprising:
initiating an upgrade procedure that updates a source system to a target system, the upgrade procedure preparing software for the target system in parallel to operation of an application on the source system; determining, by a select trigger, that the upgrade procedure reads a first key in a production table being used both by the upgrade procedure and the application; writing, by the select trigger, the first key into a lock table; determining, by a freeze trigger after the first key is written into a lock table, that the application initiated a write request for the first key in the production table; accessing, by the freeze trigger, the lock table to identify the first key as being locked; and preventing the application from writing to the first key in the production table based on the identification in the lock table.