Athena

Prerequisites

• By default, Athena authentication uses role-based access. You will need the trust policy prepopulated with the data syncing service's identifier to grant access. It should look similar to the following JSON object with a proper service account identifier:

Step 1: Create a destination bucket, service policy, and role

Create Athena target bucket

Follow these steps to create a bucket to be used for staging data before transferring to a destination.

1. Navigate to the S3 service page.
2. Click Create bucket.
3. Enter a Bucket name, select an AWS Region, and modify any of the default settings as desired. Note: Object Ownership can be set to "ACLs disabled" and Block Public Access settings for this bucket can be set to "Block all public access" as recommended by AWS. Make note of the Bucket name and AWS Region.
4. Click Create bucket.

Create Athena access policy

1. Navigate to the IAM service page, click on the Policies navigation tab, and click Create policy.
2. Click the JSON tab, and paste the following policy, being sure to replace ACCOUNT_ID, WORKGROUP, BUCKET_NAME and SCHEMA with the your account information.
   • WORKGROUP should be primary unless otherwise specified during connection configuration.
   • BUCKET should refer to the bucket created in the previous step.
   • SCHEMA used below does not need to be created ahead of time. If it does not exist, it will be created automatically before transferring data.

{
    "Version": "2012-10-17",
    "Statement": [
        {
            "Sid": "AllowAthenaAccess",
            "Effect": "Allow",
            "Action": [
                "athena:GetQueryResults",
                "athena:StartQueryExecution",
                "athena:StopQueryExecution",
                "athena:StartSession",
                "athena:GetDatabase",
                "athena:GetDataCatalog",
                "athena:GetWorkGroup",
                "athena:GetTableMetadata",
                "athena:GetQueryExecution"
            ],
            "Resource": [
                "arn:aws:athena:*:ACCOUNT_ID:workgroup/WORKGROUP"
            ]
        },
        {
            "Sid": "AllowGlueAccessToDestinationDatabaseAndTables",
            "Effect": "Allow",
            "Action": [
                "glue:GetDatabases",
                "glue:GetDatabase",
                "glue:GetTables",
                "glue:GetTable",
                "glue:GetPartitions",
                "glue:CreateTable",
                "glue:CreateDatabase",
                "glue:UpdateTable",
                "glue:DeleteTable"
            ],
            "Resource": [
                "arn:aws:glue:*:ACCOUNT_ID:catalog",
                "arn:aws:glue:*:ACCOUNT_ID:database/SCHEMA",
                "arn:aws:glue:*:ACCOUNT_ID:database/default",
                "arn:aws:glue:*:ACCOUNT_ID:table/SCHEMA/*"
            ]
        },
        {
            "Sid": "AllowS3AccessToBucket",
            "Effect": "Allow",
            "Action": [
                "s3:PutObject",
                "s3:ListBucket",
                "s3:GetBucketLocation",
                "s3:GetObject",
                "s3:DeleteObject"
            ],
            "Resource": [
                "arn:aws:s3:::BUCKET_NAME",
                "arn:aws:s3:::BUCKET_NAME/*"
            ]
        }
    ]
}

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Athena vs. S3 permissions

Because Athena uses S3 as the underlying storage layer, the Resource access requested in the policy is scoped down via resource-specific permissions in the S3 actions.

3. Click through to the Review step, choose a name for the policy, for example, transfer-service-policy (this will be referenced in the next step), add a description, and click Create policy.

Create role

1. Navigate to the IAM service page.
2. Navigate to the Roles navigation tab, and click Create role.
3. Select Custom trust policy and paste the provided trust policy (from the prerequisite) to allow AssumeRole access to this role. Click Next.
4. Add the permissions policy created above, and click Next.
5. Enter a Role name, for example, transfer-role, and click Create role.
6. Once successfully created, search for the created role in the Roles list, click the role name, and make a note of the ARN value.

🚧

Alternative authentication method: AWS User with HMAC Access Key ID & Secret Access Key

Role based authentication is the preferred authentication mode for Athena based on AWS recommendations, however, HMAC Access Key ID & Secret Access Key is an alternative authentication method that can be used if preferred.

1. Navigate to the IAM service page.
2. Navigate to the Users navigation tab, and click Add users.
3. Enter a User name for the service, for example, transfer-service, click Next. Under Select AWS access type, select the Access key - Programatic access option. Click Next: Permissions.
4. Click the Attach existing policies directly option, and search for the name of the policy created in the previous step. Select the policy, and click Next: Tags.
5. Click Next: Review and click Create user.
6. In the Success screen, record the Access key ID and the Secret access key.

Step 2: Add your destination

1. Securely share your database, schema, workgroup, bucket name, bucket region, and IAM Role ARN with us to complete the connection.

Step 3: Data Management

Follow these guidelines to manage your new Athena tables effectively:

Optimize Iceberg Queries

To optimize the performance of your Iceberg tables, use the OPTIMIZE command. This command reorganizes the data in a way that improves query efficiency. Execute the following query periodically:

OPTIMIZE iceberg_table REWRITE DATA;

Set Vacuum Properties

Iceberg tables can accumulate snapshots over time, which can affect performance. To manage this, set the maximum age for snapshots that the vacuum process should retain:

ALTER TABLE iceberg_table SET TBLPROPERTIES (
  'vacuum_max_snapshot_age_seconds'='259200');

The default setting is 432000 seconds, we recommend only updating this if you notice degrading performance.

Perform Time Travel Queries

Iceberg supports accessing historical data snapshots using time travel queries. This feature allows you to query the table as it appeared at a previous point in time, which is useful for audits and rollbacks:

SELECT * FROM iceberg_table FOR TIMESTAMP AS OF timestamp;

Replace timestamp with the specific UNIX timestamp of the snapshot you wish to query.