Snowflake Postgres version upgrades¶
Postgres uses an X.Y versioning scheme, with X being the major version and Y being the minor version within that major version.
Postgres major version upgrades¶
Snowflake Postgres allows you to schedule your major version upgrades via an instance Modify action, which requires failover maintenance.
To initiate a major version upgrade, you must use a role that has been granted the OWNERSHIP or OPERATE privilege on the instance.
Note
You can only upgrade to a newer major version. You can’t downgrade to a previous major version.
You can combine a major version upgrade with an instance resize by selecting a new instance size, storage size, or both along with the new version number.
Tip
Since upgrade maintenance failovers can take longer than other instance Modify maintenance failovers (see below) and you can’t downgrade an instance to a prior major version, Snowflake strongly recommends that you fully test major version upgrades with a Fork of your instance before proceeding with major version upgrades of active production instances.
In the navigation menu, select Postgres.
Select your Snowflake Postgres instance.
In the Manage menu at the top right, select Modify.
If a newer version is available, you will be able to select it from the Postgres version dropdown menu.
Select the Save button to confirm the change.
You can initiate a major version upgrade with the ALTER POSTGRES INSTANCE command by setting the POSTGRES_VERSION parameter to the desired version.
This will upgrade an instance named my_instance to Postgres 18:
To have the upgrade proceed as soon as the upgrade replacement instance is ready, regardless of the currently set maintenance window:
This will both upgrade the instance to Postgres 18 and change its storage size to 100GB:
Let’s say today’s date is March 18, 2026, and you want to have the upgrade maintenance failover happen tomorrow at 10pm:
Note
If you have no maintenance window set, and have not specified a run time with APPLY ON '<timestamp>' when creating the upgrade action
via SQL, the upgrade maintenance failover will proceed as soon as the new instance is populated and ready, just as when using
APPLY IMMEDIATELY when creating the upgrade action via SQL.
When using APPLY ON '<timestamp> to schedule the upgrade maintenance failover for a specified future time, that time can be at most
three days from the current time.
How major version upgrade maintenances work¶
Postgres major version upgrades work differently than other instance management operations. Once you initiate the process, Snowflake Postgres will execute the following steps:
Just as with other Modify actions, a hidden replica is provisioned for the upgrade.
When the scheduled maintenance time arrives:
The current primary instance is locked to prevent writes.
The hidden replica is upgraded using pg_upgrade. The duration depends on the number of objects in your database, not data size.
Fail over to the newly upgraded instance once the upgrade is complete.
Important Notes:
Major Version changes can affect application compatibility. We recommend testing your application against the new PostgreSQL version before upgrading.
Read Replicas can’t have their major versions upgraded separately from their primary instances. Instead they are automatically upgraded when performing a major version upgrade on their primary, but only once their primary is upgraded and a fresh backup is taken. Until then, replicas will remain available but in a stale state.
HA instances (if present) are also automatically upgraded after their primary is upgraded and a fresh backup is taken. Until then, the primary will not have a valid HA instance present.
The service interruption from the maintenance failover will be longer than that required for other Modify actions, but should typically last no longer than a few minutes.
If an upgrade fails, your instance will automatically revert back to the original instance.
Postgres minor version upgrades¶
Snowflake will automatically upgrade your database with new minor versions of Postgres over time.
With each Postgres release we examine all security related issues and bugs. For any deemed critical, we will prioritize your upgrade to ensure that your data is safe. If an emergency update is required, we’ll perform that update during your maintenance window.
For non-critical fixes we gradually update databases by one of the following:
Updating your instance during Instance Management operations that require instance replacement, such as resource changes
Updating your High Availability standby after an HA failover. If an HA failover occurs the newly build HA instance will receive the latest point release.
An instance Refresh will also ensure your instance and HA instance (if present) will be upgraded to the latest available minor version.