Enum PlanHint 

pub enum PlanHint {
    None,
    IndexScan(String),
    SeqScan,
    Parallel(u32),
    CachePlan,
    Timeout(Duration),
    Custom(String),
}

Hints for query execution optimization.

These hints can be used by database engines to optimize query execution. Different databases support different hints - the engine implementation decides how to apply them.

Variants

None

No specific hint.

IndexScan(String)

Force use of a specific index.

SeqScan

Force a sequential scan (for analytics queries).

Parallel(u32)

Enable parallel execution.

CachePlan

Cache this query’s execution plan.

Timeout(Duration)

Set a timeout for this query.

Custom(String)

Custom database-specific hint.

Trait Implementations

impl Clone for PlanHint

fn clone(&self) -> PlanHint

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for PlanHint

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

Formats the value using the given formatter.

impl Default for PlanHint

fn default() -> PlanHint

Returns the “default value” for a type.