Maintenance in Managed Service for PostgreSQL

In Managed Service for PostgreSQL, maintenance means:

• Automatic installation of DBMS updates and revisions for hosts (including disabled clusters).
• Changes to the host class and storage size.
• Other maintenance activities.

Changing a major DBMS version is not part of maintenance. For more information about major version changes, see Upgrading the PostgreSQL version.

Maintenance windowMaintenance window

You can set the preferred maintenance time 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 procedureMaintenance procedure

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. Their queue positions are random. A replica becomes temporarily unavailable if it needs to be restarted during maintenance.

2. Master host undergoes maintenance and gets updated. If it is restarted and becomes unavailable, one of the replicas takes 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 special FQDN that always points to the master host.