Update Considerations

Read the following information carefully before you update to a new version of Exasol or revert to a previous version.

Plan

Careful planning is the best way to ensure a successful update. We recommend that you consider the following when planning your update:

• Try out the new version on a test system that closely resembles your production system before updating.

  For more information, see Test.

• Evaluate how critical this update is for your business, and plan accordingly to minimize impact.

  For example, avoid updating Exasol close to or during a critical event such as a product release, as the update will always involve some downtime.

• Read the Release Notes to understand what the changes are in the new version and how they will affect your system.

  The release notes describe the changes introduced in each new version within the Exasol 8 release cycle. For example, the change log for Exasol 8.18.1 only describes the changes between Exasol 8.18.0 and Exasol 8.18.1. To see all changes between your current version and the version you are updating to, you must therefore read the change logs for all the interim releases.

  For more information about Exasol releases and versions, see Product Life Cycle.

• Always include a full backup of data and a backup of BucketFS in your update plan.

  A backup will be required in the following scenarios:

  • When an update of the operating system is included in the new Exasol version. The update will then consist of a fresh installation followed by restoring data from a backup of your old Exasol version.
  • If the update fails and you have to roll back the update to revert to the previous version.

  For more information about backups, see Backup and Restore.

  Reverting to a previous version of Exasol will take considerably longer than an update, as it consists of a fresh installation of Exasol followed by a restore of your backed up data. Allow for the additional time when planning the update. For more details, see Revert.

  Updating from Exasol 7.1 to Exasol 8 will always require a backup. For more information, see Migrate from Exasol 7.1 to Exasol 8..

Test

Define your acceptance criteria for the new Exasol version, then install the new version and run acceptance tests on a separate test system that is as similar as possible to your production system. This will ensure that when you update your production system, it will perform as expected.

The recommended path for an update is either development environment > test > pre production > production or test > production, depending on your deployment method.

• Testing should be based on the full set of changes that were introduced between your previous Exasol version and the version you are updating to. For information about the changes in each new version, refer to the Release Notes.
• Testing should cover all your relevant business use cases. The following suggestions can be used as a starting point but should not be seen as an exclusive list.
  • In your test system, mimic the structure of your production system (users, roles, schema, tables, etc.) as much as possible.
  • If the new Exasol version supports a new version of a driver, use the latest supported version of that driver in your tests.
  • Test the most frequently used queries from your production system. Which queries that are run frequently can be deduced from the audit logs (see Auditing).
  • Run tests that mimic the typical load on your production system.
  • Test all your UDFs.
  • If the new Exasol version supports a new remote archive for backups, try storing some backups on the new remote volume.
    

Update

Because of the differences in architecture, you cannot update your database directly from Exasol 7.1 to Exasol 8. In order to migrate your database to Exasol 8 you must create a full backup of your Exasol 7.1 database and then restore that backup into a new Exasol 8 database.

For more information, see Migrate from Exasol 7.1 to Exasol 8.

Revert

If the update fails or if you experience issues after the update, you can roll back to your old version and restore the data from the backup.

1. Perform a fresh installation of your previous Exasol version on your cluster. For more information, see Installation.

2. Restore the data that you backed up before the update. For more information, see Restore Database from Backup

Restoring backed up data to the system may result in data loss from the time that you took the backup until the time that you restore it.

Contact Support

If you need assistance with the update, contact Support.