Ingres 9.2 Migration Guide - Actian

Upgrade TypesUpgradedb MethodThe upgradedb utility allows for a fast, in-place upgrade path for an olderversion Ingres database, with no additional disk space requirements. Becauseupgradedb is faster, it is typically the recommended way of upgrading.Preparing for a safe and reliable upgradedb, however, can take time, especiallywhen upgrading from Ingres 6.4.Databases using the system-maintained logical key feature are best upgradedusing upgradedb. Tables that contain SYSTEM_MAINTAINED table_key orobject_key columns cannot be safely unloaded and reloaded without additionalwork. The reload step generates all new logical key values. If there are othertables referencing the logical key columns, the new values must somehow bemanually propagated to those other tables.Unload/Reload MethodThe database unload/reload method ensures a clean start with a freshdatabase. Depending on the kind of table data, additional disk space may beneeded to perform the unloading and reloading; the space could be as large asthree to five times the space of the database that is to be upgraded. Forexample, compressed tables with wide char or varchar columns can expandsubstantially when unloaded.The unload/reload process takes longer than upgradedb, thus increasing thedowntime of the production system. However, it ensures a clean finalinstallation.A database that has been running for years, perhaps surviving a number ofsystem crashes and hardware failures, may have suffered hidden damage thatcan confuse the upgradedb utility. For example, a database that is used by asmall department or group of people may not be maintained as well as aproduction database. Such a database may have work tables owned by a userwho no longer exists, or may be missing table data files. An unload/reloadupgrade may be a better choice for this database.The typical unload/reload upgrade uses the original Ingres installation as abase. The system databases iidbdb and imadb are upgraded in-place withupgradedb, even if user databases are unloaded/reloaded. A variation of theunload/reload method uses a brand new installation (perhaps even on adifferent machine). When this is done, additional work is needed to transferiidbdb information (users, groups, roles, and database and installationprivileges) to the new installation.Planning the Upgrade 15