Upgrade Databend

This topic provides an overview of the typical steps involved in upgrading Databend.

note

New Databend versions with breaking changes might lead to incompatibilities with an earlier version. In this case, Databend will provide detailed instructions in the release log or blog for upgrading from an incompatible version.

General Principles

The upgrade of Databend follows these principles:

• A Databend upgrade literally refers to upgrading databend-query and/or databend-meta to a newer version.
• When you upgrade Databend, you upgrade databend-query and databend-meta separately. You can also choose to upgrade one of them only, as long as the new version is compatible with the other one. Check Compatibility before you upgrade.
• The versions of all query nodes in the same cluster must be identical, and all meta nodes in your deployment, whether within the same cluster or not, must run the same version.
• Generally, rollback is not supported. It is not possible to revert to a previous version after an upgrade. This is because a new version usually brings underlying data format changes that might cause incompatibility with the previous version.

Step 1. Check Compatibility

Databend highly recommends that you check compatibility between databend-meta and databend-query before upgrading just one of them. See Query-Meta Compatibility for how to do that.

Step 2. Upgrade databend-query

Kill the old databend-query and start the new version in each node:

# Shutdown old binary
killall databend-query

# Bring up new binary
databend-query -c ...

After the new version starts, check the databend-query log to make sure no errors occurred during the upgrade.

Step 3. Upgrade databend-meta

Kill the old databend-meta and start the new version in each node:

# Shutdown old binary
killall databend-meta

# Bring up new binary
databend-meta -c ...

After the new version starts, check the databend-query and databend-meta logs to make sure no errors occurred during the upgrade.