Tutorial: Create your first Apache Iceberg™ table¶

What you’ll learn¶

In this tutorial, you’ll learn how to do the following:

• Create and configure an external volume for Snowflake-managed Iceberg tables. For demonstration purposes, the tutorial creates an external volume for Amazon S3.

• Create two Iceberg tables that use Snowflake as the Iceberg catalog (Snowflake-managed tables).

• Insert data into the Iceberg tables.

• Query the Iceberg tables.

• Delete rows from an Iceberg table.

Prerequisites¶

Before you start, you should be familiar with the following:

• Snowflake object identifiers and their requirements.

• Apache Iceberg and Iceberg tables in Snowflake. For more information, see Apache Iceberg™ tables.

• Cloud object storage.

• If using S3, you should be familiar with AWS Identity and Access Management (IAM) (https://docs.aws.amazon.com/IAM/latest/UserGuide/introduction.html) and IAM policy elements (https://docs.aws.amazon.com/IAM/latest/UserGuide/reference_policies_elements.html).

You need:

• A Snowflake user with a role that has the privileges to perform the following actions:

  • CREATE WAREHOUSE

  • CREATE DATABASE

  • CREATE EXTERNAL VOLUME

  • CREATE ICEBERG TABLE

  If using a 30-day trial account, you can log in as the user that was created for the account. This user has the role with the privileges needed to create the objects.

  If you don’t have a user with the necessary permissions, ask someone who does to create one for you. Users with the ACCOUNTADMIN role can create new users and grant them the required privileges.

• Administrator access for your cloud storage provider in order to configure an external volume.

• A storage bucket (or container) with the same cloud provider, in the same region that hosts your Snowflake account.

• Access to the SNOWFLAKE_SAMPLE_DATA database in your account. Snowflake creates the sample database in new accounts by default. If the database has not been created in your account, see Using the Sample Database.

Create an IAM policy that grants access to your S3 location¶

To configure access permissions for Snowflake in the AWS Management Console, do the following:

1. Log in to the AWS Management Console.

2. From the home dashboard, search for and select IAM.

3. From the left-hand navigation pane, select Account settings.

4. Under Security Token Service (STS) in the Endpoints list, find the Snowflake region where your account is located. If the STS status is inactive, move the toggle to Active.

5. From the left-hand navigation pane, select Policies.

6. Select Create Policy.

   

7. For Policy editor, select JSON.

8. Add a policy to provide Snowflake with the required permissions to read and write data to your S3 location.

   The following example policy grants access to all locations in the specified bucket.

   Note

   • Replace my_bucket with your actual bucket name. You can also specify a path in the bucket; for example, my_bucket/path.

   • Setting the "s3:prefix": condition to ["*"] grants access to all prefixes in the specified bucket; setting it to ["path/*"] grants access to a specified path in the bucket.

   • For buckets in government regions, the bucket ARNs use the arn:aws-us-gov:s3::: prefix.

   {
      "Version": "2012-10-17",
      "Statement": [
            {
               "Effect": "Allow",
               "Action": [
                  "s3:PutObject",
                  "s3:GetObject",
                  "s3:GetObjectVersion",
                  "s3:DeleteObject",
                  "s3:DeleteObjectVersion"
               ],
               "Resource": "arn:aws:s3:::<my_bucket>/*"
            },
            {
               "Effect": "Allow",
               "Action": [
                  "s3:ListBucket",
                  "s3:GetBucketLocation"
               ],
               "Resource": "arn:aws:s3:::<my_bucket>",
               "Condition": {
                  "StringLike": {
                        "s3:prefix": [
                           "*"
                        ]
                  }
               }
            }
      ]
   }
   

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9. Select Next.

10. Enter a Policy name (for example, snowflake_access) and an optional Description.

11. Select Create policy.

Create an IAM role¶

Create an AWS IAM role to grant privileges on the S3 bucket containing your data files.

1. From the left-hand navigation pane in the Identity and Access Management (IAM) Dashboard, select Roles.

2. Select Create role.

3. For the trusted entity type, select AWS account.

4. Under An AWS account, select This account. In a later step, you modify the trust relationship and grant access to Snowflake.

5. Select the Require external ID option. Enter an external ID (https://docs.aws.amazon.com/IAM/latest/UserGuide/id_roles_create_for-user_externalid.html) of your choice. For example, iceberg_table_external_id.

   An external ID is used to grant access to your AWS resources (such as S3 buckets) to a third party like Snowflake.

   

6. Select Next.

7. Select the policy that you created for the external volume, then select Next.

8. Enter a Role name and description for the role, then select Create role.

   You have now created an IAM policy for an S3 location, created an IAM role, and attached the policy to the role.

9. Select View role to view the role summary page. Locate and record the ARN (Amazon Resource Name) value for the role.

   

Create an external volume in Snowflake¶

Create an external volume using the CREATE EXTERNAL VOLUME command. The following example creates an external volume named iceberg_external_volume that defines a single Amazon S3 storage location with encryption.

CREATE OR REPLACE EXTERNAL VOLUME iceberg_external_volume
   STORAGE_LOCATIONS =
      (
         (
            NAME = 'my-s3-us-west-2'
            STORAGE_PROVIDER = 'S3'
            STORAGE_BASE_URL = 's3://<my_bucket>/'
            STORAGE_AWS_ROLE_ARN = '<arn:aws:iam::123456789012:role/myrole>'
            STORAGE_AWS_EXTERNAL_ID = 'iceberg_table_external_id'
         )
      );

The example specifies the external ID (iceberg_table_external_id) associated with the IAM role that you created for the external volume. Specifying an external ID lets you use the same IAM role (and external ID) across multiple external volumes.

Retrieve the AWS IAM user for your Snowflake account¶

1. Retrieve the ARN for the AWS IAM user that was created automatically for your Snowflake account using the DESCRIBE EXTERNAL VOLUME command. Specify the name of your external volume.

   The following example describes an external volume named iceberg_external_volume.

   DESC EXTERNAL VOLUME iceberg_external_volume;
   

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2. Record the value for the STORAGE_AWS_IAM_USER_ARN property, which is the AWS IAM user created for your Snowflake account; for example, arn:aws:iam::123456789001:user/abc1-b-self1234.

   Snowflake provisions a single IAM user for your entire Snowflake account. All S3 external volumes in your account use that IAM user.

   Note

   If you didn’t specify an external ID (STORAGE_AWS_EXTERNAL_ID) when you created an external volume, Snowflake generates an ID for you to use. Record the value so that you can update your IAM role trust policy with the generated external ID.

Grant the IAM user permissions to access bucket objects¶

In this step, you configure permissions that allow the IAM user for your Snowflake account to access objects in your S3 bucket.

1. Log in to the AWS Management Console.

2. From the home dashboard, search for and select IAM.

3. From the left-hand navigation pane, select Roles.

4. Select the IAM role that you created for your external volume.

5. Select the Trust relationships tab.

6. Select Edit trust policy.

7. Modify the policy document with the DESC EXTERNAL VOLUME output values that you recorded.

   

   Policy document for IAM role

   {
     "Version": "2012-10-17",
     "Statement": [
       {
         "Sid": "",
         "Effect": "Allow",
         "Principal": {
           "AWS": "<snowflake_user_arn>"
         },
         "Action": "sts:AssumeRole",
         "Condition": {
           "StringEquals": {
             "sts:ExternalId": "<iceberg_table_external_id>"
           }
         }
       }
     ]
   }
   

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   Where:

   • snowflake_user_arn is the STORAGE_AWS_IAM_USER_ARN value you recorded.

   • iceberg_table_external_id is your external ID. If you already specified an external ID when you created the role, and used the same ID to create your external volume, leave the value as-is. Otherwise, update sts:ExternalId with the value that you recorded.

   Note

   You must update this policy document if you create a new external volume (or recreate an existing external volume using the CREATE OR REPLACE EXTERNAL VOLUME syntax) and don’t provide your own external ID. For security reasons, a new or recreated external volume has a different external ID and cannot resolve the trust relationship unless you update this trust policy.

8. Select Update policy to save your changes.

Create a table using the standard syntax¶

First, create an Iceberg table using the standard CREATE ICEBERG TABLE syntax.

Specify CATALOG = 'SNOWFLAKE' so that the table uses Snowflake as the Iceberg catalog.

To tell Snowflake where to write table data and metadata, specify a value for the BASE_LOCATION parameter. The example sets the table name (customer_iceberg) as the BASE_LOCATION. This way, Snowflake writes data and metadata under a directory with the same name as the table in your external volume location.

CREATE OR REPLACE ICEBERG TABLE customer_iceberg (
    c_custkey INTEGER,
    c_name STRING,
    c_address STRING,
    c_nationkey INTEGER,
    c_phone STRING,
    c_acctbal INTEGER,
    c_mktsegment STRING,
    c_comment STRING
)
    CATALOG = 'SNOWFLAKE'
    EXTERNAL_VOLUME = 'iceberg_external_volume'
    BASE_LOCATION = 'customer_iceberg';

Later in the tutorial, you load data into this table from the snowflake_sample_data.tpch_sf1.customer table in the SNOWFLAKE_SAMPLE_DATA database. The column definitions in the CREATE ICEBERG TABLE statement match the sample table.

Set the catalog integration and external volume for the database¶

Next, set the CATALOG and EXTERNAL_VOLUME parameters for the iceberg_tutorial_db that you created in this tutorial. Setting the parameters tells Snowflake to use the specific catalog and external volume that you choose for all Iceberg tables created after the change.

ALTER DATABASE iceberg_tutorial_db SET CATALOG = 'SNOWFLAKE';
ALTER DATABASE iceberg_tutorial_db SET EXTERNAL_VOLUME = 'iceberg_external_volume';

To verify, check the parameters for the current database (iceberg_tutorial_db):

SHOW PARAMETERS IN DATABASE ;

Create a table using CTAS¶

Finally, create a second Iceberg table called nation_iceberg using the CREATE ICEBERG TABLE … AS SELECT syntax. We’ll base the new table on the snowflake_sample_data.tpch_sf1.nation table in the Snowflake sample database.

CREATE OR REPLACE ICEBERG TABLE nation_iceberg (
  n_nationkey INTEGER,
  n_name STRING
)
  BASE_LOCATION = 'nation_iceberg'
  AS SELECT
    N_NATIONKEY,
    N_NAME
  FROM snowflake_sample_data.tpch_sf1.nation;