Akar Processor

Physical operator execution pipeline — the runtime that executes query plans.

Physical operators (48 structs):

• PhysicalScan — reads column-major table data into DataChunks
• PhysicalFilter — evaluates expressions, produces selection vectors
• PhysicalProjection — selects/orders columns
• PhysicalOrderBy — multi-key sorting (all Value types, NULLs last)
• PhysicalLimit — chunk-aware LIMIT/OFFSET
• PhysicalHashJoin — hash join with Value-keyed hash table (all types)
• PhysicalAggregate — scalar and GROUP BY aggregates (COUNT, SUM, AVG, MIN, MAX)
• PhysicalCopyFrom — CSV/Parquet file loading into tables
• PhysicalDelete — row deletion from node tables
• PhysicalSet — property updates on matched rows
• PhysicalUnwind — list expression expansion into rows
• PhysicalIntersect — WCOJ intersect execution
• PhysicalRecursiveExtend — recursive path traversal
• PhysicalCountRelTable — CSR metadata COUNT

Expression evaluation:

• Arrow-native evaluation (evaluate_to_arrow + boolean_array_to_selection)
• Parallel aggregation via AggregateHashTable
• Parallel hash join via JoinHashTable
• BlockMergeSort + RadixSort for ORDER BY
• BinaryHeap O(n log k) TopK

Pipeline: QueryProcessor::execute(&[LogicalOperator]) -> flattens plan -> runs physical operators -> returns Vec<DataChunk>.

Tests: 157