Abstract: A catalog of one or more metadata objects associated with metadata is stored in a persistent manner. The data objects are stored at least in part on a user node included in a data management system. A request associated with accessing a metadata object included in the persistent catalog is received. In response to receiving the request, access to the requested metadata object is provided.

Abstract: Coarse-grained system-wide database privileges are transformed into new finer-grained database object privileges that are user-centric and specific to particular objects by creating an object class defining certain generic operations on objects, and defining within the object class a new object that embodies permissible actions on a particular database object. The new object is stored in a catalog table that comprises an object privilege table and is associated in the object privilege table with a consolidated grouping of object privileges of users relative to the new object.

Abstract: A process for upgrading a mirrored shared-nothing database system comprises a sequence of short well-defined idempotent steps, and at least one non-idempotent step involving transforming a master catalog. The upgrade process is managed and controlled by a state machine that has a persistent memory running on the master node. In the event of a failure or crash during an idempotent step, the process stops the database in the current state and repeats the step. If a failure or crash occurs during a non-idempotent step, the upgrade process is rolled back to the beginning and repeated.

Abstract: A process for upgrading a mirrored shared-nothing database system comprises a sequence of short well-defined idempotent steps, and at least one non-idempotent step involving transforming a master catalog. The upgrade process is managed and controlled by a state machine that has a persistent memory running on the master node. In the event of a failure or crash during an idempotent step, the process stops the database in the current state and repeats the step. If a failure or crash occurs during a non-idempotent step, the upgrade process is rolled back to the beginning and repeated.

Abstract: A script is run on a database to transform the metadata and produce an upgraded database. A new database corresponding to the upgraded database is initialized, and the metadata in the new database catalog is verified by comparing it to the upgraded database metadata. A fast verification is performed on a partial upgrade by dumping the catalogs of master nodes and comparing the results, and a thorough verification is performed on a full upgrade by querying and comparing both master node catalogs and segment node catalogs.