SNOW-2213899: Enable hybrid execution by default (#3718)

Co-authored-by: Doris Lee <[email protected]>

Author: sfc-gh-joshi

CHANGELOG.md

@@ -27,12 +27,13 @@
 #### New Features
 
 #### Improvements
+
+- Hybrid execution mode is now enabled by default. Certain operations on smaller data will now automatically execute in native pandas in-memory. Use `from modin.config import AutoSwitchBackend; AutoSwitchBackend.disable()` to turn this off and force all execution to occur in Snowflake.
 - Downgraded to level `logging.DEBUG - 1` the log message saying that the
   Snowpark `DataFrame` reference of an internal `DataFrameReference` object
   has changed.
-
 - Eliminate duplicate parameter check queries for casing status when retrieving the session.
-- Retrieve dataframe row counts through object metadata to avoid a COUNT(*) query (performance)
+- Retrieve dataframe row counts through object metadata to avoid a COUNT(\*) query (performance)
 
 #### Dependency Updates
 

src/snowflake/snowpark/modin/plugin/__init__.py

@@ -5,6 +5,7 @@
 import inspect
 import sys
 from typing import Union, Callable, Any
+import warnings
 
 from packaging import version
 
@@ -183,8 +184,19 @@
 )
 from modin.config import AutoSwitchBackend  # isort: skip  # noqa: E402
 
+HYBRID_WARNING = (
+    "Snowpark pandas now runs with hybrid execution enabled by default, and will perform certain operations "
+    + "on smaller data using local, in-memory pandas. To disable this behavior and force all computations to occur in "
+    + "Snowflake, run this line:\nfrom modin.config import AutoSwitchBackend; AutoSwitchBackend.disable()"
+)
+
+warnings.filterwarnings("once", message=HYBRID_WARNING)
+
 if AutoSwitchBackend.get_value_source() is ValueSource.DEFAULT:
-    AutoSwitchBackend.disable()
+    AutoSwitchBackend.enable()
+
+if AutoSwitchBackend.get():
+    warnings.warn(HYBRID_WARNING, stacklevel=1)
 
 # Hybrid Mode Registration
 # In hybrid execution mode, the client will automatically switch backends when a

tests/integ/modin/hybrid/auto_switch_backend/test_plugin_default.py

@@ -3,11 +3,11 @@
 #
 
 
-def test_importing_plugin_always_turns_off_auto_switch_backend():
-    """Test that importing snowflake.snowpark.modin.plugin always turns AutoSwitchBackend off."""
+def test_importing_plugin_always_turns_on_auto_switch_backend():
+    """Test that importing snowflake.snowpark.modin.plugin always turns AutoSwitchBackend."""
 
     from modin.config import AutoSwitchBackend
 
     import snowflake.snowpark.modin.plugin  # noqa: F401
 
-    assert AutoSwitchBackend.get() is False
+    assert AutoSwitchBackend.get() is True