Session

modin.pandas.session is the Snowpark session that new Snowpark pandas DataFrames and Series will use to execute queries.

  • session starts as None.

  • When there is no active Snowpark session and session is None, accessing session or creating a Snowpark pandas Dataframe or Series will raise an exception. You will need to create a Snowpark session to acccess session or create a DataFrame or Series.

  • When there a single active Snowpark session and session is None, Snowpark pandas automatically assigns that session to session.

  • When there are multiple active Snowpark sessions and session is None, accessing session or creating a Snowpark pandas Dataframe or Series will raise an exception. To make Snowpark pandas populate modin.pandas.session, you can close one of the sessions, or assign a particular session to session. For example, if you execute modin.pandas.session = session1, Snowpark pandas will use session1.

Examples

Creating and using the default Snowpark session

If you have set a default Snowflake connection, you can use use that connection to create a Snowpark session for Snowpark pandas:

import modin.pandas as pd
import snowflake.snowpark.modin.plugin
from snowflake.snowpark import Session

# Session.builder.create() will create a default Snowflake connection.
Session.builder.create()
df = pd.DataFrame([1, 2, 3])
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Note that Snowpark pandas uses the unique active Snowpark session, even though the code does not explicitly assign that session to Snowpark pandas.

Assigning one of multiple sessions to Snowpark pandas

You can create multiple Snowpark sessions, then assign one of them to Snowpark pandas.

import modin.pandas as pd
import snowflake.snowpark.modin.plugin
from snowflake.snowpark import Session

pandas_session = Session.builder.configs({"user": "<user>", "password": "<password>", "account": "<account1>").create()
other_session = Session.builder.configs({"user": "<user>", "password": "<password>", "account": "<account2>").create()
pd.session = pandas_session
df = pd.DataFrame([1, 2, 3])
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Trying to use Snowpark pandas when there is no active Snowpark session

The code below will cause a SnowparkSessionException with a message like Snowpark pandas requires an active snowpark session, but there is none. Once you create a session, you can use Snowpark pandas.

import modin.pandas as pd
import snowflake.snowpark.modin.plugin

df = pd.DataFrame([1, 2, 3])
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Trying to use Snowpark pandas when there are multiple active Snowpark sessions

The code below will cause a SnowparkSessionException with a message like There are multiple active snowpark sessions, but you need to choose one for Snowpark pandas.

import modin.pandas as pd
import snowflake.snowpark.modin.plugin
from snowflake.snowpark import Session

pandas_session = Session.builder.configs({"user": "<user>", "password": "<password>", "account": "<account1>"}).create()
other_session = Session.builder.configs({"user": "<user>", "password": "<password>", "account": "<account2>"}).create()
df = pd.DataFrame([1, 2, 3])
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