RESERVATION_CHANGES view
The INFORMATION_SCHEMA.RESERVATION_CHANGES view contains a near real-time list
of all changes to reservations within the administration project. Each row
represents a change to a single reservation. For more information, see
  Introduction to reservations.
Required permission
To query the INFORMATION_SCHEMA.RESERVATION_CHANGES view, you need
the bigquery.reservations.list Identity and Access Management (IAM) permission on the
project.
Each of the following predefined IAM roles includes the required
permission:
- BigQuery Resource Admin (
roles/bigquery.resourceAdmin) - BigQuery Resource Editor (
roles/bigquery.resourceEditor) - BigQuery Resource Viewer (
roles/bigquery.resourceViewer) - BigQuery User (
roles/bigquery.user) - BigQuery Admin (
roles/bigquery.admin) 
For more information about BigQuery permissions, see BigQuery IAM roles and permissions.
Schema
The INFORMATION_SCHEMA.RESERVATION_CHANGES view has the
following schema:
| Column name | Data type | Value | 
|---|---|---|
change_timestamp | 
      TIMESTAMP | 
      Time when the change occurred. | 
project_id | 
      STRING | 
      ID of the administration project. | 
project_number | 
      INTEGER | 
      Number of the administration project. | 
reservation_name | 
      STRING | 
      User provided reservation name. | 
ignore_idle_slots | 
      BOOL | 
      If false, any query using this reservation can use unused idle slots from other capacity commitments. | 
action | 
      STRING | 
      Type of event that occurred with the reservation. Can be
        CREATE, UPDATE, or DELETE. | 
    
slot_capacity | 
      INTEGER | 
      Baseline of the reservation. | 
user_email | 
      STRING | 
      Email address of the user or subject of the workforce identity
        federation that made the change. google for changes
        made by Google. NULL if the email address is unknown.
       | 
    
target_job_concurrency | 
      INTEGER | 
      The target number of queries that can execute simultaneously, which is limited by available resources. If zero, then this value is computed automatically based on available resources. | 
autoscale | 
      STRUCT | 
      
         Information about the autoscale capacity of the reservation. Fields include the following: 
  | 
    
edition | 
      STRING | 
      The edition associated with this reservation. For more information about editions, see Introduction to BigQuery editions. | 
primary_location | 
      STRING | 
      The current location of the reservation's primary replica. This field is only set for reservations using the managed disaster recovery feature. | 
secondary_location | 
      STRING | 
      The current location of the reservation's secondary replica. This field is only set for reservations using the managed disaster recovery feature. | 
original_primary_location | 
      STRING | 
      The location where the reservation was originally created. | 
labels | 
      RECORD | 
      Array of labels associated with the reservation. | 
max_slots | 
      INTEGER | 
      The maximum number of slots that this reservation can use, which includes
      baseline slots (slot_capacity), idle slots (if ignore_idle_slots is false), and
      autoscale slots. This field is specified by users for using the reservation predictability feature. | 
    
scaling_mode | 
      STRING | 
      The scaling mode for the reservation, which determines how the reservation scales from baseline to max_slots. This field is specified by users for using the reservation predictability feature. | 
    
Data retention
This view contains current reservations and deleted reservations that are kept for a maximum of 41 days after which they are removed from the view.
Scope and syntax
Queries against this view must include a region qualifier. If you do not specify a regional qualifier, metadata is retrieved from all regions. The following table explains the region scope for this view:
| View name | Resource scope | Region scope | 
|---|---|---|
[PROJECT_ID].`region-REGION`.INFORMATION_SCHEMA.RESERVATION_CHANGES[_BY_PROJECT] | 
  Project level | REGION | 
  
- 
  Optional: 
PROJECT_ID: the ID of your Google Cloud project. If not specified, the default project is used. - 
  
REGION: any dataset region name. For example,`region-us`. 
Example
The following example gets the history of changes for a given reservation. Use this information to see the list of changes made to a specific reservation, such as creating or deleting the reservation.
SELECT * FROM reservation-admin-project.`region-us`. INFORMATION_SCHEMA.RESERVATION_CHANGES WHERE reservation_name = "my-reservation" ORDER BY change_timestamp DESC;