Method optimize

src/adapter/src/optimize/index.rs:140–218

(&mut self, index: Index)

    type To = GlobalMirPlan;

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

        let on_entry = self.catalog.get_entry(&index.on);
        let full_name = self
            .catalog
            .resolve_full_name(&index.name, on_entry.conn_id());
        let on_desc = on_entry
            .relation_desc()
            .expect("can only create indexes on items with a valid description");

        let mut df_builder = {
            let compute = self.compute_instance.clone();
            DataflowBuilder::new(&*self.catalog, compute).with_config(&self.config)
        };
        let mut df_desc = MirDataflowDescription::new(full_name.to_string());

        df_builder.import_into_dataflow(&index.on, &mut df_desc, &self.config.features)?;
        df_builder.maybe_reoptimize_imported_views(&mut df_desc, &self.config)?;

        let index_desc = IndexDesc {
            on_id: index.on,
            key: index.keys.clone(),
        };
        df_desc.export_index(
            self.exported_index_id,
            index_desc,
            ReprRelationType::from(on_desc.typ()),
        );

        // Prepare expressions in the assembled dataflow.
        let style = ExprPrepMaintained;
        df_desc.visit_children(
            |r| style.prep_relation_expr(r),
            |s| style.prep_scalar_expr(s),
        )?;

        // Construct TransformCtx for global optimization.
        let mut df_meta = DataflowMetainfo::default();
        let mut transform_ctx = TransformCtx::global(
            &df_builder,
            &mz_transform::EmptyStatisticsOracle, // TODO: wire proper stats
            &self.config.features,
            &self.typecheck_ctx,
            &mut df_meta,
            Some(&mut self.metrics),
        );
        // Run global optimization.
        mz_transform::optimize_dataflow(&mut df_desc, &mut transform_ctx, false)?;

        if self.config.mode == OptimizeMode::Explain {
            // Collect the list of indexes used by the dataflow at this point.
            trace_plan!(at: "global", &df_meta.used_indexes(&df_desc));
        }

        // Emit a notice if we are trying to create an empty index.
        if index.keys.is_empty() {
            df_meta.push_optimizer_notice_dedup(IndexKeyEmpty);