Upgrade and downgrade best practices

When you upgrade or downgrade your IBM® Netezza® system, you may have to create a history database to use the correct history version settings.

The history database version specifies the kind of information that the history database collects for the queries and sessions that occur on your system. Starting in Release 4.6, the history database version was 1. In Release 7.0.3, the version of the history database changed to 2 to collect information related to multiple schema support and also captures history when users change to a new database or a new schema in a session using the SET CATALOG and SET SCHEMA commands. In Release 7.1, the history version changed to 3 to collect information related to the scheduler rules that apply to queries and the client information fields that users can specify for sessions.

When you upgrade to 7.1 or later, your existing version 1 and 2 history configurations continue to work and collect data, but the information may not accurately capture changes relating to the 7.1 features. As a best practice, you should create a new version 3 history database and collect the latest information going forward. The older history databases will become dormant (that is, no new data will be loaded into them after you start using the version 3 database), but you can still query against the older history database as needed.