Method cache_statement_metadata

src/cache/enhanced_statement_pool.rs:289–324

Cache statement metadata with optimization data

(
        &self,
        cache_key: String,
        metadata: StatementMetadata,
        pattern: QueryPattern,
        hints: OptimizationHints,
    )

    /// Cache statement metadata with optimization data
    fn cache_statement_metadata(
        &self,
        cache_key: String,
        metadata: StatementMetadata,
        pattern: QueryPattern,
        hints: OptimizationHints,
    ) {
        let mut statements = self.statements.write().unwrap();
        
        // Check if we need to evict entries
        if statements.len() >= self.max_size {
            self.evict_least_valuable(&mut statements);
        }

        // Calculate priority score for this entry
        let priority_score = self.calculate_priority_score(&pattern, &hints);

        let entry = CachedStatementEntry {
            metadata,
            pattern: pattern.clone(),
            hints,
            access_count: 0,
            last_used: Instant::now(),
            created_at: Instant::now(),
            avg_execution_time: None,
            priority_score,
        };

        statements.insert(cache_key, entry);

        // Update pattern statistics
        {
            let mut stats = self.stats.write().unwrap();
            *stats.most_accessed_patterns.entry(pattern).or_insert(0) += 1;
        }
    }

    /// Calculate priority score for caching decisions
    fn calculate_priority_score(&self, pattern: &QueryPattern, hints: &OptimizationHints) -> f64 {