App Engine predefines a simple index on each property of an entity. An App
Engine application can define further custom indexes in an index configuration
file named index.yaml. You can tune indexes manually by editing
the index.yaml file before uploading the application.
Example
The following is an example of an index.yaml file:
indexes:
- kind: Cat
ancestor: no
properties:
- name: name
- name: age
direction: desc
- kind: Cat
properties:
- name: name
direction: asc
- name: whiskers
direction: desc
# This pound sign is the syntax for a comment.
- kind: Store
ancestor: yes
properties:
- name: business
direction: asc
- name: owner
direction: asc
Syntax
The syntax of index.yaml is the YAML
format. The
index.yaml file has a single list element called indexes. Each element
in the list represents an index for the application.
The index items can have the following elements:
| Element | Description |
|---|---|
kind |
Required. The kind of the entity for the query. |
properties |
A list of properties to include as columns of the index, in the order to be sorted: properties used in equality filters first, followed by the property used in inequality filters, then the sort orders and their directions. Each element in this list has the following elements:
|
ancestor |
yes if the query has an ancestor clause
(). The default is no.
|
Deploying the index configuration file
The index.yaml file can reside anywhere in your source code directory.
To deploy the dispatch configuration file without otherwise altering the currently serving version, use one of the following commands in the directory containing your dispatch file, depending on your environment:
gcloud
gcloud app deploy index.yaml
Maven
mvn appengine:deployIndex index.yaml
Gradle
gradle appengineDeployIndex index.yaml
IDE
If you use IntelliJ or Eclipse, you select the individual configuration files to be deployed using the deployment form.
Deleting unused indexes
When you change or remove an index from the index configuration, the original index is not deleted from App Engine automatically. This gives you the opportunity to leave an older version of the app running while new indexes are being built, or to revert to the older version immediately if a problem is discovered with a newer version.
When you are sure that old indexes are no longer needed, you can delete them from App Engine as follows:
gcloud datastore cleanup-indexes index.yaml
