Create AWS Glue federated datasets

This document describes how to create a federated dataset in BigQuery that's linked to an existing database in AWS Glue.

A federated dataset is a connection between BigQuery and an external data source at the dataset level. The tables in a federated dataset are automatically populated from the tables in the corresponding external data source. You can query these tables directly in BigQuery, but you cannot make modifications, additions, or deletions. However, any updates that you make in the external data source are automatically reflected in BigQuery.

Before you begin

Ensure that you have a connection to access AWS Glue data.

To create or modify a connection, follow the instructions in Connect to Amazon S3. When you create that connection, include the following policy statement for AWS Glue in your AWS Identity and Access Management policy for BigQuery. Include this statement in addition to the other permissions on the Amazon S3 bucket where the data in your AWS Glue tables is stored.
```
{
 "Effect": "Allow",
 "Action": [
   "glue:GetDatabase",
   "glue:GetTable",
   "glue:GetTables",
   "glue:GetPartitions"
 ],
 "Resource": [
   "arn:aws:glue:REGION:ACCOUNT_ID:catalog",
   "arn:aws:glue:REGION:ACCOUNT_ID:database/DATABASE_NAME",
   "arn:aws:glue:REGION:ACCOUNT_ID:table/DATABASE_NAME/*"
 ]
}
```
Replace the following:
- REGION: the AWS region—for example us-east-1
- ACCOUNT_ID:: the 12-digit AWS Account ID
- DATABASE_NAME: the AWS Glue database name

Required permissions

To get the permissions that you need to create a federated dataset, ask your administrator to grant you the BigQuery Admin (roles/bigquery.admin) IAM role. For more information about granting roles, see Manage access.

This predefined role contains the permissions required to create a federated dataset. To see the exact permissions that are required, expand the Required permissions section:

Required permissions

The following permissions are required to create a federated dataset:

bigquery.datasets.create
bigquery.connections.use
bigquery.connections.delegate

You might also be able to get these permissions with custom roles or other predefined roles.

For more information about IAM roles and permissions in BigQuery, see Introduction to IAM.

Create a federated dataset

To created a federated dataset, do the following:

bq

In a command-line environment, create a dataset by using the bq mk command:

bq --location=LOCATION mk --dataset \
    --external_source aws-glue://AWS_GLUE_SOURCE \
    --connection_id PROJECT_ID.CONNECTION_LOCATION.CONNECTION_NAME \
    DATASET_NAME

Replace the following:

LOCATION: the location of your new dataset in BigQuery—for example, aws-us-east-1. After you create a dataset, you can't change its location. You can set a default location value by using the .bigqueryrc file.
AWS_GLUE_SOURCE: the Amazon Resource Name (ARN) of the AWS Glue database—for example, arn:aws:glue:us-east-1:123456789:database/test_database.
PROJECT_ID: your BigQuery project ID.
CONNECTION_LOCATION: the location of your AWS connection—for example, aws-us-east-1.
CONNECTION_NAME: the name of your AWS connection.
DATASET_NAME: the name of your new dataset in BigQuery. To create a dataset in a project other than your default project, add the project ID to the dataset name in the following format: PROJECT_ID:DATASET_NAME.

Terraform

Use the google_bigquery_dataset resource.

To authenticate to BigQuery, set up Application Default Credentials. For more information, see Set up authentication for client libraries.

The following example creates an AWS Glue federated dataset:

resource "google_bigquery_dataset" "dataset" {
  provider                    = google-beta
  dataset_id                  = "example_dataset"
  friendly_name               = "test"
  description                 = "This is a test description."
  location                    = "aws-us-east-1"

external_dataset_reference {
  external_source = "aws-glue://arn:aws:glue:us-east-1:999999999999:database/database"
  connection      = "projects/project/locations/aws-us-east-1/connections/connection"
  }
}

To apply your Terraform configuration in a Google Cloud project, complete the steps in the following sections.

Prepare Cloud Shell

Launch Cloud Shell.
Set the default Google Cloud project where you want to apply your Terraform configurations.

You only need to run this command once per project, and you can run it in any directory.
```
export GOOGLE_CLOUD_PROJECT=PROJECT_ID
```
Environment variables are overridden if you set explicit values in the Terraform configuration file.

Prepare the directory

Each Terraform configuration file must have its own directory (also called a root module).

In Cloud Shell, create a directory and a new file within that directory. The filename must have the .tf extension—for example main.tf. In this tutorial, the file is referred to as main.tf.
```
mkdir DIRECTORY && cd DIRECTORY && touch main.tf
```
If you are following a tutorial, you can copy the sample code in each section or step.

Copy the sample code into the newly created main.tf.

Optionally, copy the code from GitHub. This is recommended when the Terraform snippet is part of an end-to-end solution.
Review and modify the sample parameters to apply to your environment.
Save your changes.
Initialize Terraform. You only need to do this once per directory.
```
terraform init
```
Optionally, to use the latest Google provider version, include the -upgrade option:
```
terraform init -upgrade
```

Apply the changes

Review the configuration and verify that the resources that Terraform is going to create or update match your expectations:
```
terraform plan
```
Make corrections to the configuration as necessary.
Apply the Terraform configuration by running the following command and entering yes at the prompt:
```
terraform apply
```
Wait until Terraform displays the "Apply complete!" message.
Open your Google Cloud project to view the results. In the Google Cloud console, navigate to your resources in the UI to make sure that Terraform has created or updated them.

API

Call the datasets.insert method with a defined dataset resource and externalDatasetReference field for your AWS Glue database.

List tables in a federated dataset

To list the tables that are available for query in your federated dataset, see Listing datasets.

Get table information

To get information on the tables in your federated dataset, such as schema details, see Get table information.

Control access to tables

To manage access to the tables in your federated dataset, see Control access to resources with IAM.

Query AWS Glue data

Querying tables in federated datasets is the same as querying tables in any other BigQuery dataset.

You can query AWS Glue tables in the following formats:

CSV (compressed and uncompressed)
JSON (compressed and uncompressed)
Parquet
ORC
Avro
Iceberg

Table mapping details

Every table that you grant access to in your AWS Glue database appears as an equivalent table in your BigQuery dataset.

Format

The format of each BigQuery table is determined by the following fields of the respective AWS Glue table:

InputFormat (Table.StorageDescriptor.InputFormat)
OutputFormat (Table.StorageDescriptor.OutputFormat)
SerializationLib (Table.StorageDescriptor.SerdeInfo.SerializationLibrary)

The only exception is Iceberg tables, which use the TableType (Table.Parameters["table_type"]) field.

For example, an AWS Glue table with the following fields is mapped to an ORC table in BigQuery:

InputFormat = "org.apache.hadoop.hive.ql.io.orc.OrcInputFormat"
OutputFormat = "org.apache.hadoop.hive.ql.io.orc.OrcOutputFormat"
SerializationLib = "org.apache.hadoop.hive.ql.io.orc.OrcSerde"

Location

The location of each BigQuery table is determined by the following:

Iceberg tables: the Table.Parameters["metadata_location"] field in the AWS Glue table
Non-Iceberg unpartitioned tables: the Table.StorageDescriptor.Location field in the AWS Glue table
Non-Iceberg partitioned tables: the AWS Glue GetPartitions API

Other properties

Additionally, some AWS Glue table properties are automatically mapped to format-specific options in BigQuery:

Format	SerializationLib	AWS Glue table value	BigQuery option
CSV	LazySimpleSerDe	Table.StorageDescriptor.SerdeInfo.Parameters["field.delim"]	CsvOptions.fieldDelimiter
CSV	LazySimpleSerDe	Table.StorageDescriptor.Parameters["serialization.encoding"]	CsvOptions.encoding
CSV	LazySimpleSerDe	Table.StorageDescriptor.Parameters["skip.header.line.count"]	CsvOptions.skipLeadingRows
CSV	OpenCsvSerDe	Table.StorageDescriptor.SerdeInfo.Parameters["separatorChar"]	CsvOptions.fieldDelimiter
CSV	OpenCsvSerDe	Table.StorageDescriptor.SerdeInfo.Parameters["quoteChar"]	CsvOptions.quote
CSV	OpenCsvSerDe	Table.StorageDescriptor.Parameters["serialization.encoding"]	CsvOptions.encoding
CSV	OpenCsvSerDe	Table.StorageDescriptor.Parameters["skip.header.line.count"]	CsvOptions.skipLeadingRows
JSON	Hive JsonSerDe	Table.StorageDescriptor.Parameters["serialization.encoding"]	JsonOptions.encoding

Create a view in a federated dataset

You can't create a view in a federated dataset. However, you can create a view in a standard dataset that's based on a table in a federated dataset. For more information, see Create views.

Delete a federated dataset

Deleting a federated dataset is the same as deleting any other BigQuery dataset. For more information, see Delete datasets.

Pricing

For information about pricing, see BigQuery Omni pricing.

Limitations

All BigQuery Omni limitations apply.
You can't add, delete, or update data or metadata in tables in an AWS Glue federated dataset.
You can't create new tables, views, or materialized views in an AWS Glue federated dataset.
You can only create an AWS Glue federated dataset through Terraform, the bq tool, and the API. The Google Cloud console and data definition language (DDL) statements aren't supported.
INFORMATION_SCHEMA views aren't supported.
Row-level security, column-level security, metadata caching, and data masking aren't supported.
Dataset-level settings that are related to table creation defaults don't affect federated datasets because you can't create tables manually.
The Apache Hive data type UNION isn't supported for Avro tables.

What's next

Learn more about BigQuery Omni.
Try the BigQuery Omni with AWS lab.