Module cost_based 

Cost-based query optimization for TLExpr.

This module implements a cost-based optimizer that:

• Generates equivalent expression rewrites
• Estimates execution cost for each alternative
• Selects the most efficient representation
• Provides backend optimization hints

Overview

The cost-based optimizer explores the space of equivalent expressions by applying rewriting rules, then uses cost estimation to select the best alternative. This is particularly useful for complex queries where there are multiple valid execution strategies.

Example

use tensorlogic_compiler::optimize::optimize_by_cost;
use tensorlogic_compiler::CompilerContext;
use tensorlogic_ir::{TLExpr, Term};

let mut ctx = CompilerContext::new();
ctx.add_domain("Person", 1000);

// Complex expression with multiple equivalent forms
let expr = TLExpr::and(
    TLExpr::pred("p", vec![Term::var("x")]),
    TLExpr::or(
        TLExpr::pred("q", vec![Term::var("x")]),
        TLExpr::pred("r", vec![Term::var("x")]),
    ),
);

let (optimized, stats) = optimize_by_cost(&expr, &ctx);
println!("Cost reduction: {:.1}%", stats.cost_reduction_percent());

Structs

CostBasedOptimizer

Cost-based optimizer that explores rewrite space.

CostBasedStats

Statistics from cost-based optimization.

Enums

RewriteRule

Rewriting rule for generating equivalent expressions.

Functions

optimize_by_cost

Optimize an expression using cost-based optimization.

optimize_by_cost_with_config

Optimize with custom parameters.