Notifications

Oxia allows applications to get a feed of all the changes happening in a given namespace. This is similar to a database change-data-capture (CDC).

Once a notification object is created, a client is guaranteed to receive notification of all the changes happening in Oxia after that point, even in the presence of an arbitrary number of failures.

Subscribing to notifications

Go


notifications, err := client.GetNotifications()
defer notifications.Close()
 
for notification := range notifications.Ch() {
    fmt.Println(notification)
}

Java


client.notifications(notification -> {
    System.out.println("Got notification: " + notification);
});

CLI


oxia client notifications

Notification event types

Name	Description
`KeyCreated`	A record that didn’t exist was created
`KeyModified`	An existing record was modified
`KeyDeleted`	A record was deleted
`KeyRangeRangeDeleted`	A range of keys was deleted

Notification event fields:

Name	Type	Description
`Type`	`NotificationType`	The type of the modification
`Key`	`string`	The Key of the record to which the notification is referring
`VersionId`	`int64`	The current VersionId of the record, or -1 for a KeyDeleted event
`KeyRangeEnd`	`string`	In case of a KeyRangeRangeDeleted notification, this would represent the end (excluded) of the range of keys

Disabling notifications

Notifications are enabled by default on namespaces. Since there is some overhead for preparing the notifications feed, if an application doesn’t need this feature it can be disabled.

In the coordinator config.yaml, set notificationsEnabled=false on the specific namespace configuration.