SNOW-807303 Use SELECT * EXCLUDE for DataFrame.drop()

CHANGELOG.md

@@ -8,6 +8,7 @@
 
 - Invoking snowflake system procedures does not invoke an additional `describe procedure` call to check the return type of the procedure.
 - Added support for `Session.create_dataframe()` with the stage URL and FILE data type.
+- Improved query generation for `Dataframe.drop` to use `SELECT * EXCLUDE ()` to exclude the dropped columns. To enable this feature, set `session.conf.set("use_simplified_query_generation", True)`.
 
 #### Bug Fixes
 

src/snowflake/snowpark/_internal/analyzer/metadata_utils.py

@@ -171,7 +171,7 @@ def infer_metadata(
                 ]
             # When source_plan doesn't have a projection, it's a simple `SELECT * from ...`,
             # which means source_plan has the same metadata as its child plan, we can use it directly
-            if source_plan.projection is None:
+            if not source_plan.has_projection:
                 # We can only retrieve the cached metadata when there is an underlying SnowflakePlan
                 # or it's a SelectableEntity
                 if source_plan.from_._snowflake_plan is not None:
@@ -231,7 +231,7 @@ def cache_metadata_if_selectable(
             # we should cache it on the child plan too.
             # This is necessary SelectStatement.select() will need the column states of the child plan
             # (check the implementation of derive_column_states_from_subquery().
-            if source_plan.projection is None:
+            if not source_plan.has_projection:
                 if source_plan.from_._snowflake_plan is not None:
                     source_plan.from_._snowflake_plan._metadata = metadata
                 elif isinstance(source_plan.from_, SelectableEntity):

src/snowflake/snowpark/_internal/analyzer/select_statement.py

@@ -718,6 +718,7 @@ def __init__(
         analyzer: "Analyzer",
         schema_query: Optional[str] = None,
         distinct: bool = False,
+        exclude_cols: Optional[Set[str]] = None,
     ) -> None:
         super().__init__(analyzer)
         self.projection: Optional[List[Expression]] = projection
@@ -731,6 +732,8 @@ def __init__(
         self._sql_query = None
         self._schema_query = schema_query
         self.distinct_: bool = distinct
+        # An optional set to store the columns that should be excluded from the projection
+        self.exclude_cols: Optional[Set[str]] = exclude_cols
         self._projection_in_str = None
         self._query_params = None
         self.expr_to_alias.update(self.from_.expr_to_alias)
@@ -772,6 +775,7 @@ def __copy__(self):
             analyzer=self.analyzer,
             schema_query=self.schema_query,
             distinct=self.distinct_,
+            exclude_cols=self.exclude_cols,
         )
         # The following values will change if they're None in the newly copied one so reset their values here
         # to avoid problems.
@@ -802,6 +806,7 @@ def __deepcopy__(self, memodict={}) -> "SelectStatement":  # noqa: B006
             # directly copy the current schema fields
             schema_query=self._schema_query,
             distinct=self.distinct_,
+            exclude_cols=self.exclude_cols,
         )
 
         _deepcopy_selectable_fields(from_selectable=self, to_selectable=copied)
@@ -820,7 +825,7 @@ def __deepcopy__(self, memodict={}) -> "SelectStatement":  # noqa: B006
     @property
     def column_states(self) -> ColumnStateDict:
         if self._column_states is None:
-            if not self.projection and not self.has_clause:
+            if not self.has_projection and not self.has_clause:
                 self.column_states = self.from_.column_states
             else:
                 super().column_states  # will assign value to self._column_states
@@ -850,24 +855,36 @@ def has_clause(self) -> bool:
             self.has_clause_using_columns or self.limit_ is not None or self.distinct_
         )
 
+    @property
+    def has_projection(self) -> bool:
+        """Boolean that indicates if the SelectStatement has the following forms of projection:
+        - select columns
+        - exclude columns
+        """
+        return self.projection is not None or self.exclude_cols is not None
+
     @property
     def projection_in_str(self) -> str:
         if not self._projection_in_str:
-            self._projection_in_str = (
-                analyzer_utils.COMMA.join(
+            if self.projection:
+                assert (
+                    self.exclude_cols is None
+                ), "We should not have reached this state. There is likely a bug in flattening logic."
+                self._projection_in_str = analyzer_utils.COMMA.join(
                     self.analyzer.analyze(x, self.df_aliased_col_name_to_real_col_name)
                     for x in self.projection
                 )
-                if self.projection
-                else analyzer_utils.STAR
-            )
+            else:
+                self._projection_in_str = analyzer_utils.STAR
+                if self.exclude_cols is not None:
+                    self._projection_in_str = f"{analyzer_utils.STAR}{analyzer_utils.EXCLUDE}({analyzer_utils.COMMA.join(sorted(self.exclude_cols))})"
         return self._projection_in_str
 
     @property
     def sql_query(self) -> str:
         if self._sql_query:
             return self._sql_query
-        if not self.has_clause and not self.projection:
+        if not self.has_clause and not self.has_projection:
             self._sql_query = self.from_.sql_query
             return self._sql_query
         from_clause = self.from_.sql_in_subquery
@@ -920,7 +937,7 @@ def attributes(self, value: Optional[List[Attribute]]):
     def schema_query(self) -> str:
         if self._schema_query:
             return self._schema_query
-        if not self.projection:
+        if not self.has_projection:
             self._schema_query = self.from_.schema_query
             return self._schema_query
         self._schema_query = f"{analyzer_utils.SELECT}{self.projection_in_str}{analyzer_utils.FROM}({self.from_.schema_query})"
@@ -1180,6 +1197,9 @@ def select(self, cols: List[Expression]) -> "SelectStatement":
         elif self.distinct_:
             # .distinct().select() != .select().distinct() therefore we cannot flatten
             can_be_flattened = False
+        elif self.exclude_cols is not None:
+            # exclude syntax only support: SELECT * EXCLUDE(col1, col2) FROM TABLE
+            can_be_flattened = False
         else:
             can_be_flattened = can_select_statement_be_flattened(
                 self.column_states, new_column_states
@@ -1303,7 +1323,7 @@ def distinct(self) -> "SelectStatement":
             and (not self.offset)
             # .order_by(col1).select(col2).distinct() cannot be flattened because
             # SELECT DISTINCT B FROM TABLE ORDER BY A is not valid SQL
-            and (not (self.order_by and self.projection))
+            and (not (self.order_by and self.has_projection))
             and not has_data_generator_exp(self.projection)
         )
         if can_be_flattened:
@@ -1325,6 +1345,42 @@ def distinct(self) -> "SelectStatement":
             new.attributes = self.attributes
         return new
 
+    def exclude(
+        self, exclude_cols: List[str], keep_cols: List[str]
+    ) -> "SelectStatement":
+        """List of quoted column names to be dropped from the current select
+        statement.
+        """
+        # .select().drop(); cannot be flattened; exclude syntax is select * exclude ...
+
+        # .order_by().drop() can be flattened
+        # .filter().drop() can be flattened
+        # .limit().drop() can be flattened
+        # .distinct().drop() can be flattened
+        can_be_flattened = not self.flatten_disabled and not self.projection
+        if can_be_flattened:
+            new = copy(self)
+            new.from_ = self.from_.to_subqueryable()
+            new.pre_actions = new.from_.pre_actions
+            new.post_actions = new.from_.post_actions
+            new._merge_projection_complexity_with_subquery = False
+        else:
+            new = SelectStatement(
+                from_=self.to_subqueryable(),
+                analyzer=self.analyzer,
+            )
+
+        new.exclude_cols = new.exclude_cols or set()
+        new.exclude_cols.update(exclude_cols)
+
+        # Use keep_cols and select logic to derive updated column_states for new
+        new_column_states = derive_column_states_from_subquery(
+            [Attribute(col, DataType()) for col in keep_cols], self
+        )
+        assert new_column_states is not None
+        new.column_states = new_column_states
+        return new
+
     def set_operator(
         self,
         *selectables: Union[
@@ -1336,7 +1392,7 @@ def set_operator(
         if (
             isinstance(self.from_, SetStatement)
             and not self.has_clause
-            and not self.projection
+            and not self.has_projection
         ):
             last_operator = self.from_.set_operands[-1].operator
             if operator == last_operator:

src/snowflake/snowpark/_internal/telemetry.py

@@ -123,7 +123,6 @@ class TelemetryField(Enum):
 API_CALLS_TO_ADJUST = {
     "to_df": 1,
     "select_expr": 1,
-    "drop": 1,
     "agg": 2,
     "distinct": 2,
     "with_column": 1,

src/snowflake/snowpark/dataframe.py

@@ -1736,7 +1736,6 @@ def select_expr(
 
     selectExpr = select_expr
 
-    @df_api_usage
     @publicapi
     def drop(
         self, *cols: Union[ColumnOrName, Iterable[ColumnOrName]], _emit_ast: bool = True
@@ -1782,48 +1781,83 @@ def drop(
                 build_expr_from_snowpark_column_or_col_name(ast.cols.args.add(), c)
             ast.cols.variadic = is_variadic
 
-        names = []
-        for c in exprs:
-            if isinstance(c, str):
-                names.append(c)
-            elif isinstance(c, Column) and isinstance(c._expression, Attribute):
-                from snowflake.snowpark.mock._connection import MockServerConnection
+        with ResourceUsageCollector() as resource_usage_collector:
+            names = []
+            for c in exprs:
+                if isinstance(c, str):
+                    names.append(c)
+                elif isinstance(c, Column) and isinstance(c._expression, Attribute):
+                    from snowflake.snowpark.mock._connection import MockServerConnection
 
-                if isinstance(self._session._conn, MockServerConnection):
-                    self.schema  # to execute the plan and populate expr_to_alias
+                    if isinstance(self._session._conn, MockServerConnection):
+                        self.schema  # to execute the plan and populate expr_to_alias
 
-                names.append(
-                    self._plan.expr_to_alias.get(
-                        c._expression.expr_id, c._expression.name
+                    names.append(
+                        self._plan.expr_to_alias.get(
+                            c._expression.expr_id, c._expression.name
+                        )
                     )
-                )
-            elif (
-                isinstance(c, Column)
-                and isinstance(c._expression, UnresolvedAttribute)
-                and c._expression.df_alias
+                elif (
+                    isinstance(c, Column)
+                    and isinstance(c._expression, UnresolvedAttribute)
+                    and c._expression.df_alias
+                ):
+                    names.append(
+                        self._plan.df_aliased_col_name_to_real_col_name.get(
+                            c._expression.name, c._expression.name
+                        )
+                    )
+                elif isinstance(c, Column) and isinstance(
+                    c._expression, NamedExpression
+                ):
+                    names.append(c._expression.name)
+                else:
+                    raise SnowparkClientExceptionMessages.DF_CANNOT_DROP_COLUMN_NAME(
+                        str(c)
+                    )
+
+            normalized_names = {quote_name(n) for n in names}
+            existing_names = [attr.name for attr in self._output]
+            keep_col_names = [c for c in existing_names if c not in normalized_names]
+            if not keep_col_names:
+                raise SnowparkClientExceptionMessages.DF_CANNOT_DROP_ALL_COLUMNS()
+
+            if self._select_statement and self._session.conf.get(
+                "use_simplified_query_generation"
             ):
-                names.append(
-                    self._plan.df_aliased_col_name_to_real_col_name.get(
-                        c._expression.name, c._expression.name
+                # Only drop the columns that exist in the DataFrame.
+                drop_normalized_names = [
+                    name for name in normalized_names if name in existing_names
+                ]
+                if not drop_normalized_names:
+                    df = self._with_plan(self._select_statement)
+                else:
+                    df = self._with_plan(
+                        self._select_statement.exclude(
+                            drop_normalized_names, keep_col_names
+                        )
                     )
-                )
-            elif isinstance(c, Column) and isinstance(c._expression, NamedExpression):
-                names.append(c._expression.name)
             else:
-                raise SnowparkClientExceptionMessages.DF_CANNOT_DROP_COLUMN_NAME(str(c))
+                df = self.select(list(keep_col_names), _emit_ast=False)
 
-        normalized_names = {quote_name(n) for n in names}
-        existing_names = [attr.name for attr in self._output]
-        keep_col_names = [c for c in existing_names if c not in normalized_names]
-        if not keep_col_names:
-            raise SnowparkClientExceptionMessages.DF_CANNOT_DROP_ALL_COLUMNS()
+        if self._session.conf.get("use_simplified_query_generation"):
+            add_api_call(
+                df,
+                "DataFrame.drop[exclude]",
+                resource_usage_collector.get_resource_usage(),
+            )
         else:
-            df = self.select(list(keep_col_names), _emit_ast=False)
+            adjust_api_subcalls(
+                df,
+                "DataFrame.drop[select]",
+                len_subcalls=1,
+                resource_usage=resource_usage_collector.get_resource_usage(),
+            )
 
-            if _emit_ast:
-                df._ast_id = stmt.uid
+        if _emit_ast:
+            df._ast_id = stmt.uid
 
-            return df
+        return df
 
     @df_api_usage
     @publicapi

src/snowflake/snowpark/mock/_nop_analyzer.py

@@ -59,6 +59,9 @@ def sort(self, cols: List[Expression]) -> "MockSelectStatement":
     def distinct(self) -> "MockSelectStatement":
         return self._make_nop_select_statement_copy(super().distinct())
 
+    def exclude(self, exclude_cols, keep_cols) -> "MockSelectStatement":
+        return super().exclude(exclude_cols, keep_cols)
+
     def set_operator(
         self,
         *selectables: Union[

src/snowflake/snowpark/mock/_plan.py

@@ -1052,6 +1052,7 @@ def execute_mock_plan(
         limit_: Optional[int] = source_plan.limit_
         offset: Optional[int] = source_plan.offset
         distinct_: bool = source_plan.distinct_
+        exclude_cols: List[str] = source_plan.exclude_cols
 
         from_df = execute_mock_plan(from_, expr_to_alias)
 
@@ -1137,6 +1138,9 @@ def execute_mock_plan(
         if distinct_:
             result_df = result_df.drop_duplicates()
 
+        if exclude_cols:
+            result_df = result_df.drop(columns=exclude_cols)
+
         return result_df
     if isinstance(source_plan, MockSetStatement):
         first_operand = source_plan.set_operands[0]