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Oracle® Database Reference 10g Release 2 (10.2) Part Number B14237-02 |
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# V$MAP_FILE_IO_STACK

`V$MAP_FILE_IO_STACK` displays the hierarchical arrangement of storage containers for files. Each row in the view represents a level in the hierarchy.

Column | Datatype | Description
--- | --- | ---
`FILE_MAP_IDX` | `NUMBER` | File index (corresponds to `FILE_MAP_IDX` in `V$MAP_FILE`)
`DEPTH` | `NUMBER` | Element depth within the I/O stack
`ELEM_IDX` | `NUMBER` | Index corresponding to element
`CU_SIZE` | `NUMBER` | Contiguous set of logical blocks of the file, in HKB units, that is resident contiguously on the element
`STRIDE` | `NUMBER` | Number of HKB between contiguous units (CU) in the file that are contiguous on this element. Used in RAID5 and striped files.
`NUM_CU` | `NUMBER` | Number of contiguous units that are adjacent to each other on this element that are separated by `STRIDE` HKB in the file. In RAID5, the number of contiguous units also include the parity stripes.
`ELEM_OFFSET` | `NUMBER` | Element offset in HKB units
`FILE_OFFSET` | `NUMBER` | Offset in HKB units from the start of the file to the first byte of the contiguous units
`DATA_TYPE` | `VARCHAR2(15)` | Datatype (`DATA`, `PARITY`, or `DATA AND PARITY`)
`PARITY_POS` | `NUMBER` | Position of the parity. Only for RAID5. This field is needed to distinguish the parity from the data part.
`PARITY_PERIOD` | `NUMBER` | Parity period. Only for RAID5.
`ID` | `NUMBER` | Unique identifier
`PARENT_ID` | `NUMBER` | Parent identifier