Component delivery

GDK for Unreal

If you're using the GDK for Unreal, this page does not apply to you.

component_delivery is an optional field in the bridge configuration section of a worker configuration file.

This field configures the set of components that a worker instance receives updates about, for entities that it receives updates about (see Active read access).

It acts as a whitelist, and takes precedence over chunk-based interest (CBI). In other words, you need to whitelist a component (or set checkoutAllInitially to true) before you can set up CBI to receive updates about it.

Filtering components

By default, only components with checkout_initially set to true are sent to the worker instance as a result of chunk-based interest. (The worker instance might receive updates on other components due to having write access authority, or because of query-based interest.)

To control component filtering, use the following fields of component_delivery:

  • checkoutAllInitially (boolean). By default, this is set to false, which means only the components with checkout_initially set to true are sent to the worker instance when it has interest in an entity.

    If set to true, all components are sent to the worker instance when it has interest in an entity.

  • override maps fully-qualified component names to component delivery settings.

    Components without an override use the default message delivery settings as specified in the default field. A worker instance only receives updates about them if checkoutAllInitially is set to true.

The four permutations of these settings for a particular component C therefore lead to the following behavior, for a worker instance W with write access permission to and interest in C:

checkoutAllInitially checkout_initially override Behavior
falseor not specified false or not specified W does not receive updates about C
true false or not specified W receives updates about C
false or not specified true W receives updates about C
true true W receives updates about C

Example structure:

"componentDelivery": {
      "default": "RELIABLE_ORDERED",
      "checkoutAllInitially": false,
      "override": {
        "improbable.Position": {
          "checkoutInitially": true
        "improbable.Metadata": {
          "checkoutInitially": true

The worker instance can also change the set of components it has interest in at runtime - see the API documentation for more details:

Component delivery and QBI

If you're using only QBI (not CBI), you need to configure the component_delivery field so that it doesn't affect you. There are also some other things you need configure. For details, see Turning off CBI.

2019-11-15 Page updated with editorial review: Added "Component delivery and QBI" and an example component delivery field structure.

Updated about a year ago

Component delivery

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