Struct CostBasedOptimizer 

pub struct CostBasedOptimizer { /* private fields */ }

Cost-based query optimizer

Implementations

impl CostBasedOptimizer

pub fn new(config: CostModelConfig) -> Self

pub fn with_plan_cache_ttl_ms(self, ttl_ms: u64) -> Self

Set plan cache TTL

pub fn with_token_budget(self, budget: u64, tokens_per_row: f64) -> Self

Set token budget for result limiting

pub fn update_stats(&self, stats: TableStats)

Update table statistics

pub fn get_stats(&self, table: &str) -> Option<TableStats>

Get table statistics

pub fn optimize( &self, table: &str, columns: Vec<String>, predicate: Option<Predicate>, order_by: Vec<(String, SortDirection)>, limit: Option<u64>, ) -> PhysicalPlan

Optimize a SELECT query

pub fn get_plan_cost(&self, plan: &PhysicalPlan) -> f64

Get estimated cost from a plan

pub fn explain(&self, plan: &PhysicalPlan) -> String

Generate EXPLAIN output

impl CostBasedOptimizer

pub fn evict_stale_plans(&self)

Evict stale entries from the plan cache.

pub fn invalidate_plan_cache(&self)

Clear the entire plan cache (call after DDL or bulk load).

pub fn collect_stats( &self, table_name: &str, row_count: u64, size_bytes: u64, column_values: HashMap<String, Vec<String>>, indices: Vec<IndexStats>, )

Collect fresh statistics for a table from row data.

Pass an iterator of (column_name, value_as_string) pairs per row. This builds column stats with distinct counts and optional histograms.

pub fn stats_age_us(&self, table: &str) -> Option<u64>

Check if stats are stale (older than threshold)