Trait QueryRouter 

pub trait QueryRouter: Send + Sync {
    // Required method
    fn route(&self, sql: &str) -> QueryTarget;
}

Classifies SQL statements and routes them to the correct engine.

The default implementation (SqlParserRouter in rhei-sync) parses the SQL AST and applies the following heuristic:

• Writes (INSERT/UPDATE/DELETE), DDL, and simple point-lookups → OLTP
• Aggregates, GROUP BY, JOINs, window functions, CTEs, subqueries → OLAP

Contract for implementors

• route must be infallible and synchronous (no I/O).
• When uncertain, prefer QueryTarget::Oltp (safety-first: writes must never accidentally go to the read-only OLAP engine).

Required Methods

fn route(&self, sql: &str) -> QueryTarget

Classify sql and return the engine that should execute it.

Implementors