ARROW-9619: [Rust] [DataFusion] Add predicate push-down

rust/datafusion/README.md

@@ -42,7 +42,7 @@ DataFusion includes a simple command-line interactive SQL utility. See the [CLI
 - [x] SQL Query Planner
 - [x] Query Optimizer
 - [x] Projection push down
-- [ ] Predicate push down
+- [x] Predicate push down
 - [x] Type coercion
 - [x] Parallel query execution
 

rust/datafusion/src/execution/context.rs

@@ -45,7 +45,9 @@ use crate::execution::physical_plan::PhysicalPlanner;
 use crate::logicalplan::{FunctionMeta, FunctionType, LogicalPlan, LogicalPlanBuilder};
 use crate::optimizer::optimizer::OptimizerRule;
 use crate::optimizer::projection_push_down::ProjectionPushDown;
-use crate::optimizer::type_coercion::TypeCoercionRule;
+use crate::optimizer::{
+    filter_push_down::FilterPushDown, type_coercion::TypeCoercionRule,
+};
 use crate::sql::{
     parser::{DFParser, FileType},
     planner::{SchemaProvider, SqlToRel},
@@ -335,6 +337,7 @@ impl ExecutionContext {
     pub fn optimize(&self, plan: &LogicalPlan) -> Result<LogicalPlan> {
         let rules: Vec<Box<dyn OptimizerRule>> = vec![
             Box::new(ProjectionPushDown::new()),
+            Box::new(FilterPushDown::new()),
             Box::new(TypeCoercionRule::new(
                 self.state
                     .lock()

rust/datafusion/src/logicalplan.rs

@@ -509,6 +509,15 @@ fn binary_expr(l: Expr, op: Operator, r: Expr) -> Expr {
     }
 }
 
+/// return a new expression with a logical AND
+pub fn and(left: &Expr, right: &Expr) -> Expr {
+    Expr::BinaryExpr {
+        left: Box::new(left.clone()),
+        op: Operator::And,
+        right: Box::new(right.clone()),
+    }
+}
+
 /// Create a column expression based on a column name
 pub fn col(name: &str) -> Expr {
     Expr::Column(name.to_owned())