Maintenance in Managed Service for PostgreSQL

Maintenance in Managed Service for PostgreSQL includes:

• Automatic installation of DBMS updates and patches for hosts (including for stopped clusters).
• Scheduled automatic storage expansion.
• Other maintenance activities.

A major DBMS version update is not part of maintenance. For more information about major version changes, see PostgreSQL version upgrade.

Maintenance windowMaintenance window

You can set the maintenance window when creating a cluster or updating its settings:

• The arbitrary option (default) allows performing maintenance at any time.
• The by schedule option allows setting the preferred maintenance start day and time (UTC). For example, you can choose a time when the cluster is least loaded.

Maintenance workflowMaintenance workflow

In Managed Service for PostgreSQL single-host clusters, a master host undergoes maintenance. Therefore, it may become unavailable in case it is restarted.

In multi-host clusters, the maintenance is run as follows:

1. Replica hosts undergo maintenance one by one. The replicas are queued randomly. If a replica needs to be restarted during maintenance, it will become unavailable.

2. Master host undergoes maintenance and gets updated. If the master host needs to restart and becomes unavailable, one of the replicas will assume its role.

   If you access a cluster using the FQDN of the master host, the cluster may become unavailable. To make your application continuously available, access the cluster using a specific FQDN that always points to the master host.