This section describes the process of editing the attributes of a Universal Messaging channel.

Editing channels using the Enterprise Manager enables you to change specific attributes of a channel, such as name, event time to live (TTL), capacity, channel keys or even the realm on which the channel exists.

When a channel is edited, its attributes and any events found on the channel will be copied into a temporary channel, the old channel is then removed and then the new channel is created. The original events are then copied from the temporary channel onto the new channel.

As far as possible, channel events are held in memory for performance reasons. The temporary channel is also held in memory, and requires the same amount of memory as the channel being edited. The realm server must be able to allocate sufficient memory to store the temporary copy, otherwise the channel edit operation will be aborted and an error will be logged. If such a situation occurs, you can resolve it by allocating additional heap size, so that the temporary copy can exist in memory at the same time as the channel being edited.

Since editing a channel involves removing the existing channel, this will end all active subscriptions to the channel. It will also end all shared durables attached to the channel, along with the associated messages. Such subscriptions or shared durables need to be recreated after you have finished editing the channel.

In order to edit a channel, select it in the namespace and then after right-clicking on the node, a menu will be displayed with the various options for a channel node. The image below shows this menu.

By selecting the 'Edit Channel' option, you will be presented with a dialog that allows you to modify the details of the channel. These details not only include the channel attributes, but also the realm to which the channel belongs. The image below shows the edit channel dialog.

The Parent Realm field shows a drop down list containing all the names of the realms that the enterprise manager is currently connected to. By selecting a realm name from the list, it is possible to move the selected channel to any of the available realms. Clicking on the 'OK' button will perform the edit operation on the channel.

There are also a number of Storage Properties associated with the channel which can be configured by clicking the "Edit..." button to the right of "Storage Properties".