- **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` - ![[ex_hash.svg|200x200]] - **Operates on**: [[Result Set]] - **Workloads**: - [[IO]] - [[BufFileRead]] - [[BufFileWrite]] - [[LWLock]] - [[ParallelHashJoin]] - [[IPC]] - [[HashBuildAllocate]] - [[HashBuildElect]] - [[HashGrowBatchesElect]] - [[HashGrowBucketsElect]]