Akar Planner

Logical query plan construction from bound statements.

Logical operators (58 variants):

• ScanNode / ScanRel — table scans
• Filter — predicate evaluation
• Projection — column selection
• OrderBy — sorting (multi-key, ASC/DESC)
• Limit — limit + offset
• HashJoin / CrossProduct — join strategies
• Aggregate — scalar and GROUP BY
• Flatten — factorization unwinding
• Union — concatenation
• Intersect — WCOJ intersect
• SemiJoin / RecursiveExtend — traversal
• TableFunctionCall — extension table functions
• +12 DDL operators

Passes through: LogicalOperator tree with children_mut(), visit_bottom_up() helpers.

Tests: 21