Struct Tables 

pub struct Tables { /* private fields */ }

The table indices an expression reads, worked out once per expression.

Cached because the passes after this one ask the same question of the same expression many times: join ordering asks it of every condition once per subset it enumerates, which is the one place in the optimizer where a repeated walk of an expression tree would show up in a profile. Filter pushdown asks once per predicate per join and would be fine without it.

Implementations

impl Tables

pub fn new() -> Self

A cache with nothing in it.

pub fn of(&mut self, plan: &Plan, expr: ExprRef) -> TableSet

The table indices expr reads.

Handed back by value rather than by reference, since the recursion needs the cache back before it can union what the operands answered, and a set is one word for every sixty four tables in the query.

Trait Implementations

impl Debug for Tables

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for Tables

fn default() -> Tables

Returns the “default value” for a type.