![[assets/ex_indexscan.png|256]] - **Description**: Scans a table using an index. - **Performance**: Depends on index and query selectivity. - **Factors**: Index size, disk I/O cost. - **Cost**: `index cost + cpu_index_tuple_cost * index entries scanned` - ![[assets/ex_index_scan.svg|200x200]] - **Operates on**: [[Structures/Index|Index]] - **Workloads**: - [[Workloads/IO]] - [[Workloads/Sub/DataFileRead]] - [[Workloads/Sub/DataFilePrefetch]] - [[Workloads/LWLock]] - [[Workloads/Sub/BufferContent]] - [[Workloads/Sub/BufferMapping]] - [[Workloads/Lock]] - [[Workloads/Sub/relation]] - [[Workloads/Sub/page]]