Boost and bury media recommendations

This page explains how to change the ranking position of media recommendations returned by the model by using boost serving controls (also called controls).

A boost control changes the order of the recommendations after those recommendations have been returned by the model. You apply a filter expression to the results to identify which recommendations you want to boost or bury, and then you apply a boost value between -1 and +1. A boost value of +1 gives the biggest boost to a recommendation, placing it at the top of recommendations returned. A value of -1 buries the recommendation towards the bottom of the list of recommendations returned.

Boost is a serving-time control. First, the recommendations model returns a list of recommendations. Using a serving config, the boost control is then applied to that list to adjust the ranking of the recommendations. The boost control doesn't add or delete recommendations, but it does control the order in which the recommendations are presented to the user.

Boost versus filtering recommendations

Boost is a soft filter. Whereas, the regular filter for recommendations, described in Filter recommendations is a hard filter.

If you apply a hard filter to recommendations, you'll never see the documents that are filtered out. However, with a soft filter, you don't remove documents from the list of recommendations. Instead, the filter is used to determine which documents should be higher or lower in the list of recommendations returned.

Avoid swamping your recommendations model

When applying a boost or bury filter, small values close to zero are recommended. Values close to +1 or -1 are likely to overwhelm the recommendations model, so that the recommendations ranking applied by the model is not reflected in the order that the user sees the recommendations.

For example, if you boost animated movies with +1, users would only see animated movies at the top of the recommendations list; these would push non-animated movies that were highly recommended by the model to the bottom of the list where the user might not see them.

Demoting versus burying

Demoting and burying both move recommendations to lower positions in the list of returned recommendations that they'd appear otherwise.

However, demotion is based on the age of the content or on whether the user has already watched some of the content. For more information about demotion, see Demote media recommendations.

Burying applies to content identified by a filter. The filter can be any data field marked as filterable in the schema. For general information about recommendation filters including how to mark a field as filterable, see Filter recommendations.

About boost controls and serving configs

Each boost serving control is made up of a filter and a boost value. For example, one boost control boosts movies with Christmas in the title with a value of 0.1 and another buries horror movies with a value of-0.2.

After creating one or more boost controls, you attach the controls to a serving config. When any Vertex AI Search app is created, a default serving config is also automatically created. The serving config is referenced at serving time to determine what results the app generates. In addition to boost controls, the serving config can contain other types of controls, such as diversify and demote controls.

The serving config can be applied when you call the recommend method. All the controls in the serving config are then applied to recommendations returned by the method call.

Furthermore, you can have multiple serving configs associated with your app. This lets you apply different sets of controls in different circumstances. For example, if the recommendation request comes from a child's account, boost movies in categories suitable for children and bury unsuitable movies. Similarly, if the request comes from an account marked adult, boost titles or categories popular with adults. Alternatively, you might choose to have different serving configs for different geographic locations and boost content according to what is regionally popular. For more information about serving configs, see Create and manage media serving configs.

Boost values are additive

If you have attached multiple serving controls to a serving config, boosts and buries become additive.

For example, if you boost animated children's movies by 0.3 and animated adventure movies by 0.4, then a movie that is categorized as a children's animated adventure is boosted by 0.7.

Similarly, if a horror movie was boosted by 0.2 by one control and buried by -0.3 by another control in the same serving config, the net result would be to bury the movie by -0.1.

The sum of the boosts can exceed +1. For example, if the controls boosted animated children's movies by 0.6 and animated adventure movies by 0.5, then a children's animated adventure movie would be boosted by +1.1.

Examples of filters

The following are some examples of filters for media recommendations.

Filters on common key properties

Examples of filters on common key string properties (category, image_name, image_uri, language, title, and uri).

• Animations for kids:
  "filter": "categories: ANY(\"animation\") AND categories: ANY(\"children\")"

• Scary media:
  "filter": "categories: ANY(\"horror\", \"thriller\", \"crime\")

• Media where the title is "Christmas":
  "filter": "title: ANY(\"Christmas\")"

• Media where the first item in the images array has the name "beach ball":
  "filter": "images[0].name: ANY(\"beach ball\")"

Filters on media key properties

Examples of filters on media key properties. Media key properties begin with media_, and, in the filter syntax, the field name is prefaced with media_key_properties.. For a list of media key properties, see Google predefined schema versus custom schema.

• Media where the type is audio:
  "filter": "media_key_properties.media_type: ANY(\"audio\")"

• Media where the hash_tags array contains a string #winter:
  "filter": "media_key_properties.hash_tags: ANY(\"#winter\")"

• Media where the first element of the hash_tags array is the string #winter:
  "filter": "media_key_properties.hash_tags[0]: ANY(\"#winter\")"

Custom fields

Examples of filters on custom fields. For custom attributes, preface the field name with attributes..

• You have a custom string field, festival, in your schema to represent what film festival a movie premiered at. To filter on only those movies that premiered at Cannes:
  "filter": "attributes.festival: ANY(\"Cannes\")

• You have a custom boolean field, audio_desc, that is true when the media includes an audio description for visually impaired viewers. To filter on media with an audio descripton:
  "filter": "attributes.audio_desc: ANY(true)"

Limitations on filterable fields

The following limitations apply to boost serving controls:

• Only property fields of types string and boolean can be used in filter expressions for boost.

• You can't filter on fields nested more than one level. For example, you can filter on persons.name but you couldn't filter on a field persons.name.stage (even if such a field existed).

• Filters must be exact matches. This means that in examples, a movie called "Christmas Story" or "CHRISTMAS" wouldn't be boosted.

Before you begin

• Make sure that you have created a media recommendations app and data store. For more information, see Create a media recommendations app and data store.

• Optional: If you don't want to use the default serving config, create a new serving config by following steps 1-5 and 7 in Create a serving config. If your app is in production, Google recommends that you create a separate serving config for testing boost controls before applying the controls to your production serving config.

• Make sure that any fields that you want to use in your boost control are marked as Filterable in the schema. For more information, see Configure field settings. See also Filtering limits.

Boost or bury recommendations

This procedure describes how to create boost controls and attach the controls to a serving config.

After the controls have been attached to the serving config, you can specify the serving config when calling the servingConfigs.recommend method and the boost control will be used to influence the order of the recommendations returned.

Update the boost control

This procedure describes how to update an existing boost control to change the value of the boost or the filter.

After you have tested the boost control, you might discover that you want to make the boost stronger or weaker. Alternatively, you might want to change the filter string.

When updating a boost value or filter, you call the engines.controls.patch method.

The patch method replaces the values of boost and filter with the new values that you provide. This procedure shows how to edit the boost value (step 3) and the filter value (step 4) separately. However, you want to edit both, you can do that in a single curl command.

Delete a boost control

This procedure describes how to delete a boost control. If you're not using a boost control, best practice is to delete it so that you don't reach or exceed the quota for the number of controls allowed.

When deleting a boost control, you call the engines.controls.delete method.

Boost controls that are attached to a serving config can't be deleted. If you try to delete a boost control, an error message gives you the name of the serving config. You then need to delete that serving config or detach that control from the serving config.

Update a serving config to remove a boost control

Before you can delete a boost control, you have to detach it from all serving controls. Do this by patching the serving controls to remove the ID of the boost control.

To detach boost controls from a serving config, follow these steps:

1. Find out which boost controls are attached to the serving config by making a engines.servingConfigs.get request and looking at the boostControlIds field in the response.

   curl -X GET \
   -H "Authorization: Bearer $(gcloud auth print-access-token)" \
   -H "Content-Type: application/json" \
   -H "X-Goog-User-Project: PROJECT_ID" \
   "https://discoveryengine.googleapis.com/v1beta/projects/PROJECT_ID/locations/global/collections/default_collection/engines/APP_ID/servingConfigs/CONFIG_ID"
   

   • PROJECT_ID: the ID of your Google Cloud project.

   • APP_ID: the ID of the Vertex AI Search app.

   • CONFIG_ID: the ID of the serving config that you want to know more about.

   Example command and result

   curl -X GET \
   -H "Authorization: Bearer $(gcloud auth print-access-token)" \
   -H "Content-Type: application/json" \
   -H "X-Goog-User-Project: my-project-123" \
   "https://discoveryengine.googleapis.com/v1beta/projects/my-project-123/locations/global/collections/default_collection/engines/my-app/servingConfigs/my_app-1234567_id"
   

   {
     "name": "projects/123456/locations/global/collections/default_collection/engines/my-app/servingConfigs/my_app-1234567_id",
     "displayName": "jane-day-test-serving-config-for-boost-bury",
     "solutionType": "SOLUTION_TYPE_RECOMMENDATION",
     "modelId": "my-app",
     "diversityLevel": "no-diversity",
     "diversityType": "RULE_BASED_DIVERSITY",
     "mediaConfig": {},
     "createTime": "2024-11-22T23:54:45.613178Z",
     "updateTime": "2024-11-26T20:28:11.967439Z",
     "boostControlIds": [
       "boost-kids",
       "bury-horror"
     ]
   }
   

   This command lists information about the serving config my_app-1234567_id, in particular, it shows that the serving config has two boost controls attached to it: boost-kids and bury-horror.

2. To update the serving config to remove one boost control, use the engines.servingConfigs.patch method.

   curl -X PATCH -H "Authorization: Bearer $(gcloud auth print-access-token)" \
   -H "Content-Type: application/json" \
   -H "X-Goog-User-Project: PROJECT_ID" \
   "https://discoveryengine.googleapis.com/v1beta/projects/PROJECT_ID/locations/global/collections/default_collection/engines/APP_ID/servingConfigs/CONFIG_ID?update_mask=boost_control_ids" \
   -d '{
     "boostControlIds": ["CONTROL_ID"]
   }'
   

   • CONFIG_ID: the ID of the serving config that you want to attach the boost controls to—for example, my_app-1234567_id. See the previous step.

   • CONTROL_ID: contains the IDs one or more of the boost control that you want the serving config to have. Make sure to omit any boost controls that you want to delete. This is an array of strings. If you have more than one ID, don't forget to use separating quotes and commas—for example, boost-1", "boost-2.

   Example command and result: leaves one control

   curl -X PATCH \
   -H "Authorization: Bearer $(gcloud auth print-access-token)" \
   -H "Content-Type: application/json" \
   -H "X-Goog-User-Project: my-project-123" \
   "https://discoveryengine.googleapis.com/v1beta/projects/my-project-123/locations/global/collections/default_collection/engines/my-app/servingConfigs/my_app-1234567_id?update_mask=boost_control_ids" \
   -d '{
     "boostControlIds": ["bury-horror"]
   }'
   

   {
     "name": "projects/123456/locations/global/collections/default_collection/engines/my-app/servingConfigs/my_app-1234567_id",
     "displayName": "jane-day-test-serving-config-for-boost-bury",
     "solutionType": "SOLUTION_TYPE_RECOMMENDATION",
     "modelId": "my-app",
     "diversityLevel": "no-diversity",
     "diversityType": "RULE_BASED_DIVERSITY",
     "mediaConfig": {},
     "boostControlIds": [
       "bury-horror"
     ]
   }
   

   This command keeps the bury-horror boost control attached to the serving config and removes the boost-kids control. Assuming that boost-kids isn't attached to any other serving config, it can now be deleted. See Delete a boost control.

   Example command and result: removes all controls

   curl -X PATCH \
   -H "Authorization: Bearer $(gcloud auth print-access-token)" \
   -H "Content-Type: application/json" \
   -H "X-Goog-User-Project: my-project-123" \
   "https://discoveryengine.googleapis.com/v1beta/projects/my-project-123/locations/global/collections/default_collection/engines/my-app/servingConfigs/my_app-1234567_id?update_mask=boost_control_ids" \
   -d '{
   "boostControlIds": []
   }'
   

   {
   "name": "projects/123456/locations/global/collections/default_collection/engines/my-app/servingConfigs/my_app-1234567_id",
   "displayName": "jane-day-test-serving-config-for-boost-bury",
   "solutionType": "SOLUTION_TYPE_RECOMMENDATION",
   "modelId": "my-app",
   "diversityLevel": "no-diversity",
   "diversityType": "RULE_BASED_DIVERSITY",
   "mediaConfig": {}
   }
   

   This command removes all boost controls from the serving config, my_app-1234567_id