- David Sciaraffa, Software Development Manager – IBM Db2 Availability
Administration of most software systems require the periodic update of software levels. This will usually come as the result of proactively applying preventative fixes; the desire to use a new feature; or re-actively because an urgent fix is needed.
In Db2, software updates are provided in various ways, and an experienced database administrator will be familiar with each.
Db2 Software Delivery Vehicles
- Version
A Db2 version or release is a momentous collection of new feature and functionality. Db2 Version 11.1 is the successor of Version 10.5, 10.1, 9.7, 9.5, 9.1, 8.2, 8.1, 7.2, 7.1, and so on. New Db2 versions are released on a periodic basis usually in the range of 18-32 months. Deploying new Db2 versions require an upgrade procedure to modify database meta data and catalogs. Fallback compatibility between Db2 versions is never possible (described later).
- Modification Pack
A Db2 Modification Pack is also a collection of significant feature and functionality. However, it differs from a new version in that no upgrade procedure is required. Db2 modification packs are usually fallback compatible (described later). At the time of this writing, the most recent modification pack of Db2 is "Version 11.1 Modification Pack 2 Fix Pack 2" (abbreviated as 11.1.2.2). Prior to Version 11.1, Db2 did not use modification pack nomenclature.
- Fix Pack and iFix
A Db2 Fix Pack is a collection of mostly stability fixes on a specific release or modification pack. The scope of these fixes are generally not significant and there is usually no new feature or functionality. Fix Packs are released on a periodic basis, usually approximately every 3-4 months for brand new releases, and stretching to approximately every 12 months for older mature releases. Prior to version 11.1 (before Db2 adopted the modification pack nomenclature), some Fix Packs did contain significant feature and because of this may not have been fallback compatible (described later).
An iFix is a type of Fix Pack, however the fixes included in an iFix are limited to those of highest impact and minimal risk.
- Special Builds
A Db2 special build is a Db2 delivery vehicle used to include one or few fixes for problems which a customer has encountered. Often these fixes are new and not yet available in a fix pack. Special builds are usually not provided on a proactive basis. Special builds are built on top of the fixpack level which the customer has deployed, and often cumulatively built on top of an existing special build which was previously provided to the customer.
Special builds may also come in the form of 'Debug builds' which contain small changes to assist with the root cause determination of a problem, and are usually only temporarily deployed.
Fallback Compatibility
Planning for the deployment of a new version, modification pack, or fix pack will require a back-out strategy or plan. Once a database is running on a newer version/mod/fix pack, consideration is needed for whether the database data structures, backup images, and transaction log files are still compatible with the previous version/mod/fix pack.
A detailed technote has been published to describe the many nuances of fallback compatibility, and should help in the assembly of a back-out strategy:
Compatibility between DB2 for LUW Version 11.1 Mod-Packs and Fix-Packs:
http://www-01.ibm.com/support/docview.wss?uid=swg22003131
I hope this information is useful. If you have any thoughts or questions, feel free to submit a comment below.
A great explanation! thanks!
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