- **Description**: Merges sorted results from multiple subqueries. - **Performance**: Merges sorted results, efficient for large datasets. - **Factors**: Number and size of input datasets. - **Cost**: Sum of sorted subquery costs. - ![[ex_merge_append.svg|200x200]] - **Operates on**: [[Result Set]] - **Workloads**: - [[LWLock]] - [[BufferContent]] - [[IPC]] - [[AppendReady]]