opt_state.rs

use bitflags::bitflags;

bitflags! {
#[derive(Copy, Clone, Debug)]
    /// Allowed optimizations.
    pub struct OptFlags: u32 {
        /// Only read columns that are used later in the query.
        const PROJECTION_PUSHDOWN = 1;
        /// Apply predicates/filters as early as possible.
        const PREDICATE_PUSHDOWN = 1 << 2;
        /// Cluster sequential `with_columns` calls to independent calls.
        const CLUSTER_WITH_COLUMNS = 1 << 3;
        /// Run many type coercion optimization rules until fixed point.
        const TYPE_COERCION = 1 << 4;
        /// Run many expression optimization rules until fixed point.
        const SIMPLIFY_EXPR = 1 << 5;
        /// Do type checking of the IR.
        const TYPE_CHECK = 1 << 6;
        /// Pushdown slices/limits.
        const SLICE_PUSHDOWN = 1 << 7;
        /// Run common-subplan-elimination. This elides duplicate plans and caches their
        /// outputs.
        const COMM_SUBPLAN_ELIM = 1 << 8;
        /// Run common-subexpression-elimination. This elides duplicate expressions and caches their
        /// outputs.
        const COMM_SUBEXPR_ELIM = 1 << 9;

        // const STREAMING = 1 << 10; // Legacy flag for removed old streaming engine.

        const NEW_STREAMING = 1 << 11;
        /// Run every node eagerly. This turns off multi-node optimizations.
        const EAGER = 1 << 12;
        /// Try to estimate the number of rows so that joins can determine which side to keep in memory.
        const ROW_ESTIMATE = 1 << 13;
        /// Replace simple projections with a faster inlined projection that skips the expression engine.
        const FAST_PROJECTION = 1 << 14;
        /// Collapse slower joins with filters into faster joins.
        const COLLAPSE_JOINS = 1 << 15;
        /// Check if operations are order dependent and unset maintaining_order if
        /// the order would not be observed.
        const CHECK_ORDER_OBSERVE = 1 << 16;
    }
}

impl OptFlags {
    pub fn schema_only() -> Self {
        Self::TYPE_COERCION | Self::TYPE_CHECK
    }

    pub fn eager(&self) -> bool {
        self.contains(OptFlags::EAGER)
    }

    pub fn cluster_with_columns(&self) -> bool {
        self.contains(OptFlags::CLUSTER_WITH_COLUMNS)
    }

    pub fn collapse_joins(&self) -> bool {
        self.contains(OptFlags::COLLAPSE_JOINS)
    }

    pub fn predicate_pushdown(&self) -> bool {
        self.contains(OptFlags::PREDICATE_PUSHDOWN)
    }

    pub fn projection_pushdown(&self) -> bool {
        self.contains(OptFlags::PROJECTION_PUSHDOWN)
    }
    pub fn simplify_expr(&self) -> bool {
        self.contains(OptFlags::SIMPLIFY_EXPR)
    }
    pub fn slice_pushdown(&self) -> bool {
        self.contains(OptFlags::SLICE_PUSHDOWN)
    }
    pub fn new_streaming(&self) -> bool {
        self.contains(OptFlags::NEW_STREAMING)
    }
    pub fn fast_projection(&self) -> bool {
        self.contains(OptFlags::FAST_PROJECTION)
    }
}

impl Default for OptFlags {
    fn default() -> Self {
        Self::from_bits_truncate(u32::MAX) & !Self::NEW_STREAMING & !Self::EAGER
    }
}

/// AllowedOptimizations
pub type AllowedOptimizations = OptFlags;