- **Description**: Collects and merges sorted results from parallel workers. - **Performance**: Efficient for large datasets, uses memory. - **Factors**: Dataset size, available memory, CPU costs. - **Cost**: `cpu_operator_cost * number of tuples` - ![[assets/ex_hash.svg|200x200]] - **Operates on**: [[Structures/Result Set]] - **Workloads**: - [[Workloads/IO]] - [[Workloads/Sub/BufFileRead]] - [[Workloads/Sub/BufFileWrite]] - [[Workloads/LWLock]] - [[Workloads/Sub/ParallelHashJoin]] - [[Workloads/IPC]] - [[Workloads/Sub/HashBuildAllocate]] - [[Workloads/Sub/HashBuildElect]] - [[Workloads/Sub/HashGrowBatchesElect]] - [[Workloads/Sub/HashGrowBucketsElect]]