villebro / PyAthena

PyAthena is a Python DB API 2.0 (PEP 249) client for Amazon Athena.

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PyAthena

PyAthena is a Python DB API 2.0 (PEP 249) client for Amazon Athena.

Requirements

  • Python
    • CPython 3.6, 3.7 3.8 3.9

Installation

Extra packages:

Package Install command Version
Pandas pip install PyAthena[Pandas] >=1.0.0
SQLAlchemy pip install PyAthena[SQLAlchemy] >=1.0.0, <2.0.0

Usage

Basic usage

Cursor iteration

Query with parameter

Supported DB API paramstyle is only PyFormat. PyFormat only supports named placeholders with old % operator style and parameters specify dictionary format.

if % character is contained in your query, it must be escaped with %% like the following:

SQLAlchemy

Install SQLAlchemy with pip install "SQLAlchemy>=1.0.0, <2.0.0" or pip install PyAthena[SQLAlchemy]. Supported SQLAlchemy is 1.0.0 or higher and less than 2.0.0.

The connection string has the following format:

awsathena+rest://{aws_access_key_id}:{aws_secret_access_key}@athena.{region_name}.amazonaws.com:443/{schema_name}?s3_staging_dir={s3_staging_dir}&...

If you do not specify aws_access_key_id and aws_secret_access_key using instance profile or boto3 configuration file:

awsathena+rest://:@athena.{region_name}.amazonaws.com:443/{schema_name}?s3_staging_dir={s3_staging_dir}&...

NOTE: s3_staging_dir requires quote. If aws_access_key_id, aws_secret_access_key and other parameter contain special characters, quote is also required.

Pandas

As DataFrame

You can use the pandas.read_sql_query to handle the query results as a DataFrame object.

NOTE: Poor performance when using pandas.read_sql #222

The pyathena.pandas.util package also has helper methods.

If you want to use the query results output to S3 directly, you can use PandasCursor. This cursor fetches query results faster than the default cursor. (See benchmark results.)

To SQL

You can use pandas.DataFrame.to_sql to write records stored in DataFrame to Amazon Athena. pandas.DataFrame.to_sql uses SQLAlchemy, so you need to install it.

The location of the Amazon S3 table is specified by the s3_dir parameter in the connection string. If s3_dir is not specified, s3_staging_dir parameter will be used. The following rules apply.

s3://{s3_dir or s3_staging_dir}/{schema}/{table}/

The data format only supports Parquet. The compression format is specified by the compression parameter in the connection string.

The pyathena.pandas.util package also has helper methods.

This helper method supports partitioning.

Conversion to Parquet and upload to S3 use ThreadPoolExecutor by default. It is also possible to use ProcessPoolExecutor.

DictCursor

DictCursor retrieve the query execution result as a dictionary type with column names and values.

You can use the DictCursor by specifying the cursor_class with the connect method or connection object.

It can also be used by specifying the cursor class when calling the connection object's cursor method.

The basic usage is the same as the Cursor.

If you want to change the dictionary type (e.g., use OrderedDict), you can specify like the following.

AsynchronousCursor

AsynchronousCursor is a simple implementation using the concurrent.futures package. This cursor does not follow the DB API 2.0 (PEP 249).

You can use the AsynchronousCursor by specifying the cursor_class with the connect method or connection object.

It can also be used by specifying the cursor class when calling the connection object's cursor method.

The default number of workers is 5 or cpu number * 5. If you want to change the number of workers you can specify like the following.

The execute method of the AsynchronousCursor returns the tuple of the query ID and the future object.

The return value of the future object is an AthenaResultSet object. This object has an interface that can fetch and iterate query results similar to synchronous cursors. It also has information on the result of query execution.

A query ID is required to cancel a query with the AsynchronousCursor.

NOTE: The cancel method of the future object does not cancel the query.

AsynchronousDictCursor

AsyncDIctCursor is an AsyncCursor that can retrieve the query execution result as a dictionary type with column names and values.

You can use the DictCursor by specifying the cursor_class with the connect method or connection object.

It can also be used by specifying the cursor class when calling the connection object's cursor method.

The basic usage is the same as the AsyncCursor.

If you want to change the dictionary type (e.g., use OrderedDict), you can specify like the following.

PandasCursor

PandasCursor directly handles the CSV file of the query execution result output to S3. This cursor is to download the CSV file after executing the query, and then loaded into DataFrame object. Performance is better than fetching data with Cursor.

You can use the PandasCursor by specifying the cursor_class with the connect method or connection object.

It can also be used by specifying the cursor class when calling the connection object's cursor method.

The as_pandas method returns a DataFrame object.

Support fetch and iterate query results.

The DATE and TIMESTAMP of Athena's data type are returned as pandas.Timestamp type.

Execution information of the query can also be retrieved.

If you want to customize the Dataframe object dtypes and converters, create a converter class like this:

Specify the combination of converter functions in the mappings argument and the dtypes combination in the types argument.

Then you simply specify an instance of this class in the convertes argument when creating a connection or cursor.

If you want to change the NaN behavior of Pandas Dataframe, you can do so by using the keep_default_na, na_values and quoting arguments of the cursor object's execute method.

NOTE: PandasCursor handles the CSV file on memory. Pay attention to the memory capacity.

AsyncPandasCursor

AsyncPandasCursor is an AsyncCursor that can handle Pandas DataFrame. This cursor directly handles the CSV of query results output to S3 in the same way as PandasCursor.

You can use the AsyncPandasCursor by specifying the cursor_class with the connect method or connection object.

It can also be used by specifying the cursor class when calling the connection object's cursor method.

The default number of workers is 5 or cpu number * 5. If you want to change the number of workers you can specify like the following.

The execute method of the AsynchronousPandasCursor returns the tuple of the query ID and the future object.

The return value of the future object is an AthenaPandasResultSet object. This object has an interface similar to AthenaResultSetObject.

This object also has an as_pandas method that returns a DataFrame object similar to the PandasCursor.

The DATE and TIMESTAMP of Athena's data type are returned as pandas.Timestamp type.

As with AsynchronousCursor, you need a query ID to cancel a query.

Quickly re-run queries

You can attempt to re-use the results from a previously executed query to help save time and money in the cases where your underlying data isn't changing. Set the cache_size or cache_expiration_time parameter of cursor.execute() to a number larger than 0 to enable caching.

The unit of expiration_time is seconds. To use the results of queries executed up to one hour ago, specify like the following.

If cache_size is not specified, the value of sys.maxsize will be automatically set and all query results executed up to one hour ago will be checked. Therefore, it is recommended to specify cache_expiration_time together with cache_size like the following.

Results will only be re-used if the query strings match exactly, and the query was a DML statement (the assumption being that you always want to re-run queries like CREATE TABLE and DROP TABLE).

The S3 staging directory is not checked, so it's possible that the location of the results is not in your provided s3_staging_dir.

Credentials

Support Boto3 credentials.

Additional environment variable:

Examples

Passing credentials as parameters

Multi-factor authentication

You will be prompted to enter the MFA code. The program execution will be blocked until the MFA code is entered.

Shared credentials file

The shared credentials file has a default location of ~/.aws/credentials.

If you use the default profile, there is no need to specify credential information.

You can also specify a profile other than the default.

Assume role provider

Assume role provider with MFA

You will be prompted to enter the MFA code. The program execution will be blocked until the MFA code is entered.

Instance profiles

No need to specify credential information.

Testing

Depends on the following environment variables:

And you need to create a workgroup named test-pyathena with the Query result location configuration.

Run test

Run test multiple Python versions

Code formatting

The code formatting uses black and isort.

Appy format

Check format

About

PyAthena is a Python DB API 2.0 (PEP 249) client for Amazon Athena.

License:MIT License


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