Zero downtime maintenance in constrained systems

A non-transitory computer-readable storage medium coupled to one or more processors and having instructions stored thereon which, when executed by the one or more processors, cause the one or more processors to perform operations for deploying upgrade packages during a zero downtime upgrade of a database system in production use, the operations comprising:

• executing the zero downtime upgrade, during which the database system is in production use and one or more tables of a database are accessed through a bridge schema;
• receiving an upgrade package, the upgrade package defining one or more changes to be deployed to a target version of the database system that has already undergone partial deployment during a zero downtime upgrade, and comprising one or more objects having respective object types, the partial deployment altering a state of the target database system and at least partially constraining subsequent changes to the target version of the database system;
• receiving a deployment configuration, the deployment configuration providing a plurality of lists of object types for respective constraints, each object type indicating a component of the target version of the database system to be affected by the deployment configuration, and, for each list of object types, specifying a deployment option for the object types in the respective list of object types, deployment options comprising a standard deployment procedure, and an extended deployment procedure;
• determining a set of object types included in the upgrade package, the set of object types comprising one or more object types;
• and
• selectively permitting deployment of the upgrade package using the extended deployment procedure to execute at least one change corresponding to a grey-listed object type before switching the target version of the database system to production.

A system, comprising:

• a computing device;
• and
• a computer-readable storage device coupled to the computing device and having instructions stored thereon which, when executed by the computing device, cause the computing device to perform operations for deploying upgrade packages during a zero downtime upgrade of a database system in production use, the operations comprising:
• executing the zero downtime upgrade, during which the database system is in production use and one or more tables of a database are accessed through a bridge schema;
• receiving an upgrade package, the upgrade package defining one or more changes to be deployed to a target version of the database system that has already undergone partial deployment during a zero downtime upgrade, and comprising one or more objects having respective object types, the partial deployment altering a state of the target database system and at least partially constraining subsequent changes to the target version of the database system;
• receiving a deployment configuration, the deployment configuration providing a plurality of lists of object types for respective constraints, each object type indicating a component of the target version of the database system to be affected by the deployment configuration, and, for each list of object types, specifying a deployment option for the object types in the respective list of object types, deployment options comprising a standard deployment procedure, and an extended deployment procedure;
• determining a set of object types included in the upgrade package, the set of object types comprising one or more object types;
• and
• selectively permitting deployment of the upgrade package using the extended deployment procedure to execute at least one change corresponding to a grey-listed object type before switching the target version of the database system to production.