lambda-pyathena 1.4.1

Python DB API 2.0 (PEP 249) compliant client for Amazon Athena

PyAthena

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

lambda-pyathena

lambda-pyathena is a fork of PyAthena that simply removes boto3 and botocore from the install-requires, resulting in an AWS Lambda friendly package.

Requirements

• Python

  • CPython 2,7, 3,4, 3.5, 3.6

Installation

$ pip install lambda-pyathena

Extra packages:

Package	Install command	Version
Pandas	pip install lambda-pyathena[Pandas]	>=0.19.0
SQLAlchemy	pip install lambda-pyathena[SQLAlchemy]	>=1.0.0

Usage

Basic usage

from pyathena import connect

cursor = connect(aws_access_key_id='YOUR_ACCESS_KEY_ID',
                 aws_secret_access_key='YOUR_SECRET_ACCESS_KEY',
                 s3_staging_dir='s3://YOUR_S3_BUCKET/path/to/',
                 region_name='us-west-2').cursor()
cursor.execute("SELECT * FROM one_row")
print(cursor.description)
print(cursor.fetchall())

Cursor iteration

from pyathena import connect

cursor = connect(aws_access_key_id='YOUR_ACCESS_KEY_ID',
                 aws_secret_access_key='YOUR_SECRET_ACCESS_KEY',
                 s3_staging_dir='s3://YOUR_S3_BUCKET/path/to/',
                 region_name='us-west-2').cursor()
cursor.execute("SELECT * FROM many_rows LIMIT 10")
for row in cursor:
    print(row)

Query with parameter

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

from pyathena import connect

cursor = connect(aws_access_key_id='YOUR_ACCESS_KEY_ID',
                 aws_secret_access_key='YOUR_SECRET_ACCESS_KEY',
                 s3_staging_dir='s3://YOUR_S3_BUCKET/path/to/',
                 region_name='us-west-2').cursor()
cursor.execute("""
               SELECT col_string FROM one_row_complex
               WHERE col_string = %(param)s
               """, {'param': 'a string'})
print(cursor.fetchall())

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

SELECT col_string FROM one_row_complex
WHERE col_string = %(param)s OR col_string LIKE 'a%%'

SQLAlchemy

Install SQLAlchemy with pip install SQLAlchemy>=1.0.0 or pip install PyAthena[SQLAlchemy]. Supported SQLAlchemy is 1.0.0 or higher.

from urllib.parse import quote_plus  # PY2: from urllib import quote_plus
from sqlalchemy.engine import create_engine
from sqlalchemy.sql.expression import select
from sqlalchemy.sql.functions import func
from sqlalchemy.sql.schema import Table, MetaData

conn_str = 'awsathena+rest://{aws_access_key_id}:{aws_secret_access_key}@athena.{region_name}.amazonaws.com:443/'\
           '{schema_name}?s3_staging_dir={s3_staging_dir}'
engine = create_engine(conn_str.format(
    aws_access_key_id=quote_plus('YOUR_ACCESS_KEY_ID'),
    aws_secret_access_key=quote_plus('YOUR_SECRET_ACCESS_KEY'),
    region_name='us-west-2',
    schema_name='default',
    s3_staging_dir=quote_plus('s3://YOUR_S3_BUCKET/path/to/')))
many_rows = Table('many_rows', MetaData(bind=engine), autoload=True)
print(select([func.count('*')], from_obj=many_rows).scalar())

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}&...

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

Minimal example for Pandas DataFrame:

from pyathena import connect
import pandas as pd

conn = connect(aws_access_key_id='YOUR_ACCESS_KEY_ID',
               aws_secret_access_key='YOUR_SECRET_ACCESS_KEY',
               s3_staging_dir='s3://YOUR_S3_BUCKET/path/to/',
               region_name='us-west-2')
df = pd.read_sql("SELECT * FROM many_rows", conn)
print(df.head())

As Pandas DataFrame:

from pyathena import connect
from pyathena.util import as_pandas

cursor = connect(aws_access_key_id='YOUR_ACCESS_KEY_ID',
                 aws_secret_access_key='YOUR_SECRET_ACCESS_KEY',
                 s3_staging_dir='s3://YOUR_S3_BUCKET/path/to/',
                 region_name='us-west-2').cursor()
cursor.execute("SELECT * FROM many_rows")
df = as_pandas(cursor)
print(df.describe())

If you want to use Pandas DataFrame object directly, you can use PandasCursor.

AsynchronousCursor

AsynchronousCursor is a simple implementation using the concurrent.futures package. Python 2.7 uses backport of the concurrent.futures package. This cursor is not DB API 2.0 (PEP 249) compliant.

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

from pyathena import connect
from pyathena.async_cursor import AsyncCursor

cursor = connect(s3_staging_dir='s3://YOUR_S3_BUCKET/path/to/',
                 region_name='us-west-2',
                 cursor_class=AsyncCursor).cursor()

from pyathena.connection import Connection
from pyathena.async_cursor import AsyncCursor

cursor = Connection(s3_staging_dir='s3://YOUR_S3_BUCKET/path/to/',
                    region_name='us-west-2',
                    cursor_class=AsyncCursor).cursor()

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

from pyathena import connect
from pyathena.async_cursor import AsyncCursor

cursor = connect(s3_staging_dir='s3://YOUR_S3_BUCKET/path/to/',
                 region_name='us-west-2').cursor(AsyncCursor)

from pyathena.connection import Connection
from pyathena.async_cursor import AsyncCursor

cursor = Connection(s3_staging_dir='s3://YOUR_S3_BUCKET/path/to/',
                    region_name='us-west-2').cursor(AsyncCursor)

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.

from pyathena import connect
from pyathena.async_cursor import AsyncCursor

cursor = connect(s3_staging_dir='s3://YOUR_S3_BUCKET/path/to/',
                 region_name='us-west-2',
                 cursor_class=AsyncCursor).cursor(max_workers=10)

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

from pyathena import connect
from pyathena.async_cursor import AsyncCursor

cursor = connect(s3_staging_dir='s3://YOUR_S3_BUCKET/path/to/',
                 region_name='us-west-2',
                 cursor_class=AsyncCursor).cursor()

query_id, future = cursor.execute("SELECT * FROM many_rows")

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.

from pyathena import connect
from pyathena.async_cursor import AsyncCursor

cursor = connect(s3_staging_dir='s3://YOUR_S3_BUCKET/path/to/',
                 region_name='us-west-2',
                 cursor_class=AsyncCursor).cursor()

query_id, future = cursor.execute("SELECT * FROM many_rows")
result_set = future.result()
print(result_set.state)
print(result_set.state_change_reason)
print(result_set.completion_date_time)
print(result_set.submission_date_time)
print(result_set.data_scanned_in_bytes)
print(result_set.execution_time_in_millis)
print(result_set.output_location)
print(result_set.description)
for row in result_set:
    print(row)

from pyathena import connect
from pyathena.async_cursor import AsyncCursor

cursor = connect(s3_staging_dir='s3://YOUR_S3_BUCKET/path/to/',
                 region_name='us-west-2',
                 cursor_class=AsyncCursor).cursor()

query_id, future = cursor.execute("SELECT * FROM many_rows")
result_set = future.result()
print(result_set.fetchall())

A query ID is required to cancel a query with the asynchronous cursor.

from pyathena import connect
from pyathena.async_cursor import AsyncCursor

cursor = connect(s3_staging_dir='s3://YOUR_S3_BUCKET/path/to/',
                 region_name='us-west-2',
                 cursor_class=AsyncCursor).cursor()

query_id, future = cursor.execute("SELECT * FROM many_rows")
cursor.cancel(query_id)

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

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 a cursor.

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

from pyathena import connect
from pyathena.pandas_cursor import PandasCursor

cursor = connect(s3_staging_dir='s3://YOUR_S3_BUCKET/path/to/',
                 region_name='us-west-2',
                 cursor_class=PandasCursor).cursor()

from pyathena.connection import Connection
from pyathena.pandas_cursor import PandasCursor

cursor = Connection(s3_staging_dir='s3://YOUR_S3_BUCKET/path/to/',
                    region_name='us-west-2',
                    cursor_class=PandasCursor).cursor()

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

from pyathena import connect
from pyathena.pandas_cursor import PandasCursor

cursor = connect(s3_staging_dir='s3://YOUR_S3_BUCKET/path/to/',
                 region_name='us-west-2').cursor(PandasCursor)

from pyathena.connection import Connection
from pyathena.pandas_cursor import PandasCursor

cursor = Connection(s3_staging_dir='s3://YOUR_S3_BUCKET/path/to/',
                    region_name='us-west-2').cursor(PandasCursor)

The as_pandas method returns DataFrame object.

from pyathena.connection import Connection
from pyathena.pandas_cursor import PandasCursor

cursor = connect(s3_staging_dir='s3://YOUR_S3_BUCKET/path/to/',
                 region_name='us-west-2',
                 cursor_class=PandasCursor).cursor()

df = cursor.execute("SELECT * FROM many_rows").as_pandas()
print(df.describe())
print(df.head())

Support fetch and iterate query results.

from pyathena.connection import Connection
from pyathena.pandas_cursor import PandasCursor

cursor = connect(s3_staging_dir='s3://YOUR_S3_BUCKET/path/to/',
                 region_name='us-west-2',
                 cursor_class=PandasCursor).cursor()

cursor.execute("SELECT * FROM many_rows")
print(cursor.fetchone())
print(cursor.fetchmany())
print(cursor.fetchall())

from pyathena.connection import Connection
from pyathena.pandas_cursor import PandasCursor

cursor = connect(s3_staging_dir='s3://YOUR_S3_BUCKET/path/to/',
                 region_name='us-west-2',
                 cursor_class=PandasCursor).cursor()

cursor.execute("SELECT * FROM many_rows")
for row in cursor:
    print(row)

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

from pyathena.connection import Connection
from pyathena.pandas_cursor import PandasCursor

cursor = connect(s3_staging_dir='s3://YOUR_S3_BUCKET/path/to/',
                 region_name='us-west-2',
                 cursor_class=PandasCursor).cursor()

cursor.execute("SELECT col_timestamp FROM one_row_complex")
print(type(cursor.fetchone()[0]))  # <class 'pandas._libs.tslibs.timestamps.Timestamp'>

Execution information of the query can also be retrieved.

from pyathena.connection import Connection
from pyathena.pandas_cursor import PandasCursor

cursor = connect(s3_staging_dir='s3://YOUR_S3_BUCKET/path/to/',
                 region_name='us-west-2',
                 cursor_class=PandasCursor).cursor()

cursor.execute("SELECT * FROM many_rows")
print(cursor.state)
print(cursor.state_change_reason)
print(cursor.completion_date_time)
print(cursor.submission_date_time)
print(cursor.data_scanned_in_bytes)
print(cursor.execution_time_in_millis)
print(cursor.output_location)

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

Credentials

Support Boto3 credentials.

Additional environment variable:

$ export AWS_ATHENA_S3_STAGING_DIR=s3://YOUR_S3_BUCKET/path/to/

Testing

Depends on the following environment variables:

$ export AWS_ACCESS_KEY_ID=YOUR_ACCESS_KEY_ID
$ export AWS_SECRET_ACCESS_KEY=YOUR_SECRET_ACCESS_KEY
$ export AWS_DEFAULT_REGION=us-west-2
$ export AWS_ATHENA_S3_STAGING_DIR=s3://YOUR_S3_BUCKET/path/to/

Run test

$ pip install pipenv
$ pipenv install --dev
$ pipenv run scripts/test_data/upload_test_data.sh
$ pipenv run pytest
$ pipenv run scripts/test_data/delete_test_data.sh

Run test multiple Python versions

$ pip install pipenv
$ pipenv install --dev
$ pipenv run scripts/test_data/upload_test_data.sh
$ pyenv local 3.6.5 3.5.5 3.4.8 2.7.14
$ pipenv run tox
$ pipenv run scripts/test_data/delete_test_data.sh