#1354

README.md

@@ -76,12 +76,7 @@ Designed for data analytics in environments where decisions need to be replayabl
 
 ### __Fast__
 
-Benchmarks on M1 Pro Mac running an ad hoc `GROUP BY` over a 1Gb parquet file via the CLI in ~1/5th of a second, from a cold start. _(different systems will have different performance characteristics)_
-
-Rows    | Columns | File Size | Query Time
-------- | ------- | --------- | ----------
-561225  |      81 |       1Gb | 0.22sec
-1064539 |      81 |       2Gb | 0.27sec
+Benchmarks on M2 Pro Mac running an ad hoc `GROUP BY` over a 6 million row parquet file via the CLI in ~1/4th of a second from a cold start (no caching and predefined schema). _(different systems will have different performance characteristics)_
 
 ### __Instant Elasticity__
 

opteryx/__version__.py

@@ -1,4 +1,4 @@
-__build__ = 180
+__build__ = 184
 
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.

opteryx/components/heuristic_optimizer/__init__.py

@@ -65,13 +65,15 @@
 
 class HeuristicOptimizerVisitor:
     def __init__(self):
+        from .strategies import ConstantFoldingStrategy
         from .strategies import DefragmentMorselsStrategy
         from .strategies import PredicatePushdownStrategy
         from .strategies import ProjectionPushdownStrategy
         from .strategies import SplitConjunctivePredicatesStrategy
 
         self.strategies = [
             #            DefragmentMorselsStrategy(),
+            ConstantFoldingStrategy(),
             SplitConjunctivePredicatesStrategy(),
             PredicatePushdownStrategy(),
             ProjectionPushdownStrategy(),

opteryx/components/heuristic_optimizer/strategies/__init__.py

@@ -1,3 +1,4 @@
+from .constant_folding import ConstantFoldingStrategy
 from .defragment_morsels import DefragmentMorselsStrategy
 from .predicate_pushdown import PredicatePushdownStrategy
 from .projection_pushdown import ProjectionPushdownStrategy

opteryx/components/heuristic_optimizer/strategies/constant_folding.py

@@ -0,0 +1,94 @@
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import datetime
+from typing import Any
+
+import numpy
+from orso.types import OrsoTypes
+
+from opteryx.components.logical_planner import LogicalPlan
+from opteryx.components.logical_planner import LogicalPlanNode
+from opteryx.components.logical_planner import LogicalPlanStepType
+from opteryx.managers.expression import NodeType
+from opteryx.managers.expression import evaluate
+from opteryx.managers.expression import get_all_nodes_of_type
+from opteryx.models import Node
+from opteryx.virtual_datasets import no_table_data
+
+from .optimization_strategy import HeuristicOptimizerContext
+from .optimization_strategy import OptimizationStrategy
+
+
+def build_literal_node(value: Any, root: Node):
+    # fmt:off
+    if hasattr(value, "as_py"):
+        value = value.as_py()
+
+    root.schema_column = root.schema_column.to_flatcolumn()
+    root.value = value
+    root.node_type = NodeType.LITERAL
+    if value is None:
+        root.type=OrsoTypes.NULL
+    elif isinstance(value, (bool, numpy.bool_)):
+        # boolean must be before numeric
+        root.type=OrsoTypes.BOOLEAN
+    elif isinstance(value, (str)):
+        root.type=OrsoTypes.VARCHAR
+    elif isinstance(value, (int, numpy.int64)):
+        root.type=OrsoTypes.INTEGER
+    elif isinstance(value, (numpy.datetime64, datetime.datetime)):
+        root.type=OrsoTypes.TIMESTAMP
+    elif isinstance(value, (datetime.date)):
+        root.type=OrsoTypes.DATE
+    else:
+        raise Exception("Unable to fold expression")
+    return root
+    # fmt:on
+
+
+def fold_constants(root: Node) -> Node:
+    identifiers = get_all_nodes_of_type(root, (NodeType.IDENTIFIER, NodeType.WILDCARD))
+    if len(identifiers) == 0:
+        table = no_table_data.read()
+        try:
+            result = evaluate(root, table, None)[0]
+            return build_literal_node(result, root)
+        except:
+            # what ever the reason, just skip
+            pass
+    return root
+
+
+class ConstantFoldingStrategy(OptimizationStrategy):
+    def visit(
+        self, node: LogicalPlanNode, context: HeuristicOptimizerContext
+    ) -> HeuristicOptimizerContext:
+        """
+        Constant Folding is when we precalculate expressions (or sub expressions)
+        which contain only constant or literal or literal values. These don't
+        tend to happen IRL, but it's a simple enough strategy so should be
+        included.
+        """
+        if not context.optimized_plan:
+            context.optimized_plan = context.pre_optimized_tree.copy()  # type: ignore
+
+        if node.node_type == LogicalPlanStepType.Filter:
+            node.condition = fold_constants(node.condition)
+            if node.condition.node_type == NodeType.LITERAL and node.condition.value:
+                context.optimized_plan.remove_node(context.node_id, heal=True)
+
+        return context
+
+    def complete(self, plan: LogicalPlan, context: HeuristicOptimizerContext) -> LogicalPlan:
+        # No finalization needed for this strategy
+        return plan

opteryx/managers/expression/__init__.py

@@ -259,7 +259,6 @@ def _inner_evaluate(root: Node, table: Table, context: ExecutionContext):
             root.value = format_expression(root)
             root.node_type = NodeType.EVALUATED
         if node_type == NodeType.EVALUATED:
-            column = root.schema_column
             if not root.schema_column.identity in table.column_names:
                 raise ColumnReferencedBeforeEvaluationError(column=root.schema_column.name)
             return table[root.schema_column.identity].to_numpy()
@@ -308,8 +307,6 @@ def get_all_nodes_of_type(root, select_nodes):
     """
     Walk a expression tree collecting all the nodes of a specified type.
     """
-    from opteryx.third_party.travers import Graph
-
     if root is None:
         return []
     if not isinstance(root, (set, tuple, list)):

tests/misc/test_expressions.py

@@ -100,11 +100,11 @@ def test_logical_expressions():
     result = evaluate(T_AND_T, table=planets)
     assert all(result)
     result = evaluate(T_AND_F, table=planets)
-    assert not any(c.as_py() for c in result)
+    assert not any(c for c in result)
     result = evaluate(F_AND_T, table=planets)
-    assert not any(c.as_py() for c in result)
+    assert not any(c for c in result)
     result = evaluate(F_AND_F, table=planets)
-    assert not any(c.as_py() for c in result)
+    assert not any(c for c in result)
 
     T_OR_T = Node(
         NodeType.OR, left=true, right=true, schema_column=FunctionColumn(name="func", type=0)