SNOW-3308363: Feature request: connection-level `force_microsecond_precision` parameter

What is the current behavior?

When working with timestamp columns that contain values outside the nanosecond range, the per-batch Arrow timestamp resolution becomes inconsistent (timestamp[ns] vs timestamp[us]). This causes pyarrow.lib.ArrowInvalid schema mismatch errors when combining batches.

The existing force_microsecond_precision=True parameter solves this perfectly, but currently is only available on cursor.fetch_arrow_batches() and cursor.fetch_arrow_all().

What is the desired behavior?

This parameter should also be available as a connection-level parameter on snowflake.connector.connect(), so that all Arrow fetches from that connection default to microsecond precision without requiring the flag on every call.

Proposed API

import snowflake.connector

# connection-level default — all fetch_arrow_* calls use microsecond precision
con = snowflake.connector.connect(
    account='...',
    user='...',
    # ... other params
    force_microsecond_precision=True,  # new parameter
)

# these now default to force_microsecond_precision=True
cursor = con.cursor()
cursor.execute('SELECT * FROM my_table')
table = cursor.fetch_arrow_all()  # no flag needed, inherits from connection

# can still override per-call if needed
table = cursor.fetch_arrow_all(force_microsecond_precision=False)

Alternatively, this could be a session parameter or a cursor-level default — any scope broader than per-fetch-call would help.

How would this improve snowflake-connector-python?

This could provide solution in the following scenarios:

1. Downstream libraries can use it. Libraries like ibis-framework call cursor.fetch_arrow_batches() internally without passing the flag. Users have no way to inject it. A connection-level default would allow ibis (and other libraries) to inherit the behavior automatically via ibis.snowflake.from_connection(sf_con).

2. Repetitive and error-prone. In analysis workflows with many queries, forgetting the flag on a single fetch call causes a runtime error. A connection-level default eliminates this.

References and other background

Environment

• snowflake-connector-python: 4.3.0
• Python: 3.12
• OS: Windows