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Amazon Redshift

Install dlt with Redshift

To install the dlt library with Redshift dependencies:

pip install "dlt[redshift]"

Setup guide

1. Initialize the dlt project

Let's start by initializing a new dlt project as follows:

dlt init chess redshift

💡 This command will initialize your pipeline with chess as the source and Redshift as the destination.

The above command generates several files and directories, including .dlt/secrets.toml and a requirements file for Redshift. You can install the necessary dependencies specified in the requirements file by executing it as follows:

pip install -r requirements.txt

or with pip install "dlt[redshift]", which installs the dlt library and the necessary dependencies for working with Amazon Redshift as a destination.

2. Setup Redshift cluster

To load data into Redshift, you need to create a Redshift cluster and enable access to your IP address through the VPC inbound rules associated with the cluster. While we recommend asking our GPT-4 assistant for details, we have provided a general outline of the process below:

  1. You can use an existing cluster or create a new one.
  2. To create a new cluster, navigate to the 'Provisioned Cluster Dashboard' and click 'Create Cluster'.
  3. Specify the required details such as 'Cluster Identifier', 'Node Type', 'Admin User Name', 'Admin Password', and 'Database Name'.
  4. In the 'Network and Security' section, you can configure the cluster's VPC (Virtual Private Cloud). Remember to add your IP address to the inbound rules of the VPC on AWS.

3. Add credentials

  1. Next, set up the Redshift credentials in the .dlt/secrets.toml file as shown below:

    [destination.redshift.credentials]
    database = "please set me up!" # Copy your database name here
    password = "please set me up!" # Keep your Redshift db instance password here
    username = "please set me up!" # Keep your Redshift db instance username here
    host = "please set me up!" # Copy your Redshift host from cluster endpoint here
    port = 5439
    connect_timeout = 15 # Enter the timeout value
  2. The "host" is derived from the cluster endpoint specified in the “General Configuration.” For example:

    # If the endpoint is:
    redshift-cluster-1.cv3cmsy7t4il.us-east-1.redshift.amazonaws.com:5439/your_database_name
    # Then the host is:
    redshift-cluster-1.cv3cmsy7t4il.us-east-1.redshift.amazonaws.com
  3. The connect_timeout is the number of minutes the pipeline will wait before timing out.

You can also pass a database connection string similar to the one used by the psycopg2 library or SQLAlchemy. The credentials above will look like this:

# Keep it at the top of your TOML file, before any section starts
destination.redshift.credentials="redshift://loader:<password>@localhost/dlt_data?connect_timeout=15"

Write disposition

All write dispositions are supported.

Supported file formats

SQL Insert is used by default.

When staging is enabled:

caution
  • Redshift cannot load VARBYTE columns from JSON files. dlt will fail such jobs permanently. Switch to Parquet to load binaries.

  • Redshift cannot load TIME columns from JSON or Parquet files. dlt will fail such jobs permanently. Switch to direct insert_values to load time columns.

  • Redshift cannot detect compression type from JSON files. dlt assumes that JSONL files are gzip compressed, which is the default.

  • Redshift loads JSON types as strings into SUPER with Parquet. Use JSONL format to store JSON in SUPER natively or transform your SUPER columns with PARSE_JSON.

Supported column hints

Amazon Redshift supports the following column hints:

  • cluster - This hint is a Redshift term for table distribution. Applying it to a column makes it the "DISTKEY," affecting query and join performance. Check the following documentation for more info.
  • sort - This hint creates a SORTKEY to order rows on disk physically. It is used to improve query and join speed in Redshift. Please read the sort key docs to learn more.

Table and column identifiers

Redshift by default uses case-insensitive identifiers and will lower case all the identifiers that are stored in the INFORMATION SCHEMA. Do not use case-sensitive naming conventions. Letter casing will be removed anyway, and you risk generating identifier collisions, which are detected by dlt and will fail the load process.

You can put Redshift in case-sensitive mode. Configure your destination as below in order to use case-sensitive naming conventions:

[destination.redshift]
has_case_sensitive_identifiers=true

Staging support

Redshift supports s3 as a file staging destination. dlt will upload files in the parquet format to s3 and ask Redshift to copy their data directly into the db. Please refer to the S3 documentation to learn how to set up your s3 bucket with the bucket_url and credentials. The dlt Redshift loader will use the AWS credentials provided for s3 to access the s3 bucket if not specified otherwise (see config options below). Alternatively to parquet files, you can also specify jsonl as the staging file format. For this, set the loader_file_format argument of the run command of the pipeline to jsonl.

Identifier names and case sensitivity

Authentication IAM Role

If you would like to load from s3 without forwarding the AWS staging credentials but authorize with an IAM role connected to Redshift, follow the Redshift documentation to create a role with access to s3 linked to your Redshift cluster and change your destination settings to use the IAM role:

[destination]
staging_iam_role="arn:aws:iam::..."

Redshift/S3 staging example code

# Create a dlt pipeline that will load
# chess player data to the Redshift destination
# via staging on S3
pipeline = dlt.pipeline(
pipeline_name='chess_pipeline',
destination='redshift',
staging='filesystem', # add this to activate the staging location
dataset_name='player_data'
)

Additional destination options

dbt support

Syncing of dlt state

Supported loader file formats

Supported loader file formats for Redshift are sql and insert_values (default). When using a staging location, Redshift supports Parquet and JSONL.

Additional Setup guides

This demo works on codespaces. Codespaces is a development environment available for free to anyone with a Github account. You'll be asked to fork the demo repository and from there the README guides you with further steps.
The demo uses the Continue VSCode extension.

Off to codespaces!

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