AWS Athena / Glue Catalog
The Athena destination stores data as Parquet files in S3 buckets and creates external tables in AWS Athena. You can then query those tables with Athena SQL commands, which will scan the entire folder of Parquet files and return the results. This destination works very similarly to other SQL-based destinations, with the exception that the merge write disposition is not supported at this time. The dlt
metadata will be stored in the same bucket as the Parquet files, but as iceberg tables. Athena also supports writing individual data tables as Iceberg tables, so they may be manipulated later. A common use case would be to strip GDPR data from them.
Install dlt with Athenaโ
To install the dlt library with Athena dependencies:
pip install "dlt[athena]"
Setup guideโ
1. Initialize the dlt projectโ
Let's start by initializing a new dlt
project as follows:
dlt init chess athena
๐ก This command will initialize your pipeline with chess as the source and AWS Athena as the destination using the filesystem staging destination.
2. Setup bucket storage and Athena credentialsโ
First, install dependencies by running:
pip install -r requirements.txt
or with pip install "dlt[athena]"
, which will install s3fs
, pyarrow
, pyathena
, and botocore
packages.
You may also install the dependencies independently. Try
pip install dlt
pip install s3fs
pip install pyarrow
pip install pyathena
so pip does not fail on backtracking.
To edit the dlt
credentials file with your secret info, open .dlt/secrets.toml
. You will need to provide a bucket_url
, which holds the uploaded parquet files, a query_result_bucket
, which Athena uses to write query results to, and credentials that have write and read access to these two buckets as well as the full Athena access AWS role.
The TOML file looks like this:
[destination.filesystem]
bucket_url = "s3://[your_bucket_name]" # replace with your bucket name,
[destination.filesystem.credentials]
aws_access_key_id = "please set me up!" # copy the access key here
aws_secret_access_key = "please set me up!" # copy the secret access key here
[destination.athena]
query_result_bucket="s3://[results_bucket_name]" # replace with your query results bucket name
[destination.athena.credentials]
aws_access_key_id="please set me up!" # same as credentials for filesystem
aws_secret_access_key="please set me up!" # same as credentials for filesystem
region_name="please set me up!" # set your AWS region, for example "eu-central-1" for Frankfurt
If you have your credentials stored in ~/.aws/credentials
, just remove the [destination.filesystem.credentials] and [destination.athena.credentials] sections above and dlt
will fall back to your default profile in local credentials. If you want to switch the profile, pass the profile name as follows (here: dlt-ci-user
):
[destination.filesystem.credentials]
profile_name="dlt-ci-user"
[destination.athena.credentials]
profile_name="dlt-ci-user"
Additional destination configurationโ
You can provide an Athena workgroup like so:
[destination.athena]
athena_work_group="my_workgroup"
Write dispositionโ
The athena
destination handles the write dispositions as follows:
append
- files belonging to such tables are added to the dataset folder.replace
- all files that belong to such tables are deleted from the dataset folder, and then the current set of files is added.merge
- falls back toappend
(unless you're using iceberg tables).
Data loadingโ
Data loading occurs by storing parquet files in an S3 bucket and defining a schema on Athena. If you query data via SQL queries on Athena, the returned data is read by scanning your bucket and reading all relevant parquet files in there.
dlt
internal tables are saved as Iceberg tables.
Data typesโ
Athena tables store timestamps with millisecond precision, and with that precision, we generate parquet files. Keep in mind that Iceberg tables have microsecond precision.
Athena does not support JSON fields, so JSON is stored as a string.
Athena does not support TIME columns in parquet files. dlt
will fail such jobs permanently. Convert datetime.time
objects to str
or datetime.datetime
to load them.
Table and column identifiersโ
Athena uses case-insensitive identifiers and will lowercase 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.
Under the hood, Athena uses different SQL engines for DDL (catalog) and DML/Queries:
- DDL uses HIVE escaping with ``````
- Other queries use PRESTO and regular SQL escaping.
Staging supportโ
Using a staging destination is mandatory when using the Athena destination. If you do not set staging to filesystem
, dlt
will automatically do this for you.
If you decide to change the filename layout from the default value, keep the following in mind so that Athena can reliably build your tables:
- You need to provide the
{table_name}
placeholder, and this placeholder needs to be followed by a forward slash. - You need to provide the
{file_id}
placeholder, and it needs to be somewhere after the{table_name}
placeholder. {table_name}
must be the first placeholder in the layout.
Additional destination optionsโ
Iceberg data tablesโ
You can save your tables as Iceberg tables to Athena. This will enable you, for example, to delete data from them later if you need to. To switch a resource to the Iceberg table format, supply the table_format argument like this:
@dlt.resource(table_format="iceberg")
def data() -> Iterable[TDataItem]:
...
For every table created as an Iceberg table, the Athena destination will create a regular Athena table in the staging dataset of both the filesystem and the Athena glue catalog, and then copy all data into the final Iceberg table that lives with the non-Iceberg tables in the same dataset on both the filesystem and the glue catalog. Switching from Iceberg to regular table or vice versa is not supported.
merge
supportโ
The merge
write disposition is supported for Athena when using Iceberg tables.
- There is a risk of tables ending up in an inconsistent state in case a pipeline run fails mid-flight because Athena doesn't support transactions, and
dlt
uses multiple DELETE/UPDATE/INSERT statements to implementmerge
. dlt
creates additional helper tables calledinsert_<table name>
anddelete_<table name>
in the staging schema to work around Athena's lack of temporary tables.
dbt supportโ
Athena is supported via dbt-athena-community
. Credentials are passed into aws_access_key_id
and aws_secret_access_key
of the generated dbt profile. Iceberg tables are supported, but you need to make sure that you materialize your models as Iceberg tables if your source table is Iceberg. We encountered problems with materializing date-time columns due to different precision on Iceberg (nanosecond) and regular Athena tables (millisecond).
The Athena adapter requires that you set up region_name in the Athena configuration below. You can also set up the table catalog name to change the default: awsdatacatalog
[destination.athena]
aws_data_catalog="awsdatacatalog"
Syncing of dlt
stateโ
- This destination fully supports dlt state sync.. The state is saved in Athena Iceberg tables in your S3 bucket.
Supported file formatsโ
- Parquet is used by default.
Athena adapterโ
You can use the athena_adapter
to add partitioning to Athena tables. This is currently only supported for Iceberg tables.
Iceberg tables support a few transformation functions for partitioning. Info on all supported functions in the AWS documentation.
Use the athena_partition
helper to generate the partitioning hints for these functions:
athena_partition.year(column_name: str)
: Partition by year of date/datetime column.athena_partition.month(column_name: str)
: Partition by month of date/datetime column.athena_partition.day(column_name: str)
: Partition by day of date/datetime column.athena_partition.hour(column_name: str)
: Partition by hour of date/datetime column.athena_partition.bucket(n: int, column_name: str)
: Partition by hashed value ton
bucketsathena_partition.truncate(length: int, column_name: str)
: Partition by truncated value tolength
(or width for numbers)
Here is an example of how to use the adapter to partition a table:
from datetime import date
import dlt
from dlt.destinations.adapters import athena_partition, athena_adapter
data_items = [
(1, "A", date(2021, 1, 1)),
(2, "A", date(2021, 1, 2)),
(3, "A", date(2021, 1, 3)),
(4, "A", date(2021, 2, 1)),
(5, "A", date(2021, 2, 2)),
(6, "B", date(2021, 1, 1)),
(7, "B", date(2021, 1, 2)),
(8, "B", date(2021, 1, 3)),
(9, "B", date(2021, 2, 1)),
(10, "B", date(2021, 3, 2)),
]
@dlt.resource(table_format="iceberg")
def partitioned_data():
yield [{"id": i, "category": c, "created_at": d} for i, c, d in data_items]
# Add partitioning hints to the table
athena_adapter(
partitioned_data,
partition=[
# Partition per category and month
"category",
athena_partition.month("created_at"),
],
)
pipeline = dlt.pipeline("athena_example")
pipeline.run(partitioned_data)
Additional Setup guidesโ
- Load data from GitHub to AWS Athena in python with dlt
- Load data from Star Trek to AWS Athena in python with dlt
- Load data from Notion to AWS Athena in python with dlt
- Load data from Zendesk to AWS Athena in python with dlt
- Load data from Capsule CRM to AWS Athena in python with dlt
- Load data from Looker to AWS Athena in python with dlt
- Load data from Oracle Database to AWS Athena in python with dlt
- Load data from Keap to AWS Athena in python with dlt
- Load data from Jira to AWS Athena in python with dlt
- Load data from SAP HANA to AWS Athena in python with dlt