Method optimize

src/adapter/src/optimize/view.rs:90–135

(&mut self, expr: HirRelationExpr)

    type To = OptimizedMirRelationExpr;

    fn optimize(&mut self, expr: HirRelationExpr) -> Result<Self::To, OptimizerError> {
        let time = Instant::now();

        // Trace the pipeline input under `optimize/raw`.
        trace_plan!(at: "raw", &expr);

        // HIR ⇒ MIR lowering and decorrelation
        let mut expr = expr.lower(&self.config, self.metrics.as_ref())?;

        let mut df_meta = DataflowMetainfo::default();
        let mut transform_ctx = TransformCtx::local(
            &self.config.features,
            &self.typecheck_ctx,
            &mut df_meta,
            self.metrics.as_mut(),
            None,
        );

        // First, we run a very simple optimizer pipeline, which only folds constants. This takes
        // care of constant INSERTs. (This optimizer is also used for INSERTs, not just VIEWs.)
        expr = optimize_mir_constant(expr, &mut transform_ctx, self.fold_constants_limit)?;

        // MIR ⇒ MIR optimization (local)
        let expr = if expr.as_const().is_some() {
            // No need to optimize further, because we already have a constant.
            // But trace this at "local", so that `EXPLAIN LOCALLY OPTIMIZED PLAN` can pick it up.
            trace_plan!(at: "local", &expr);
            OptimizedMirRelationExpr(expr)
        } else {
            // Do the real optimization (starting with `expr_prep_style`).
            let mut opt_expr = OptimizedMirRelationExpr(expr);
            self.expr_prep_style.prep_relation_expr(&mut opt_expr)?;
            expr = opt_expr.into_inner();
            optimize_mir_local(expr, &mut transform_ctx)?
        };

        if let Some(metrics) = &self.metrics {
            metrics.observe_e2e_optimization_time("view", time.elapsed());
        }

        // TODO: Handle the `optimizer_notices` in `df_meta`.
        // https://github.com/MaterializeInc/database-issues/issues/10012

        // Return the resulting OptimizedMirRelationExpr.
        Ok(expr)
    }
}