V$IOSTAT_FILE

V$IOSTAT_FILE displays information about disk I/O statistics of database files (including data files, temp files, and other types of database files). I/O statistics for Data files and Temp files are provided for each file. All other file types (for example, control files, log files, archive logs, and so on) have their statistics consolidated into one entry in the view.

Column Datatype Description
FILE_NO NUMBER File identification number
FILETYPE_ID VARCHAR2(25) Type of file (for example, log file, data file, and so on)
FILETYPE_NAME VARCHAR2(28) Name of the file, in the case of a data file or temp file. For all other files, a corresponding string to be displayed (for example, ARCHIVELOG).
SMALL_READ_MEGABYTES NUMBER Number of single block megabytes read
SMALL_WRITE_MEGABYTES NUMBER Number of single block megabytes written
LARGE_READ_MEGABYTES NUMBER Number of multiblock megabytes read
LARGE_WRITE_MEGABYTES NUMBER Number of multiblock megabytes written
SMALL_READ_REQS NUMBER Number of single block read requests
SMALL_WRITE_REQS NUMBER Number of single block write requests
SMALL_SYNC_READ_REQS NUMBER Number of synchronous single block read requests
LARGE_READ_REQS NUMBER Number of multiblock read requests
LARGE_WRITE_REQS NUMBER Number of multiblock write requests
SMALL_READ_SERVICETIME NUMBER Total service time (in milliseconds) for single block read requests
SMALL_WRITE_SERVICETIME NUMBER Total service time (in milliseconds) for single block write requests
SMALL_SYNC_READ_LATENCY NUMBER Latency for single block synchronous reads (in milliseconds)
LARGE_READ_SERVICETIME NUMBER Total service time (in milliseconds) for multiblock read requests
LARGE_WRITE_SERVICETIME NUMBER Total service time (in milliseconds) for multiblock write requests
ASYNCH_IO VARCHAR2(9) Indicates whether asynchronous I/O is available for the file (ASYNC_ON) or not (ASYNC_OFF)
ACCESS_METHOD VARCHAR2(11) I/O library used to access the file. Possible values include:
  • OS_LIB - OS system calls are used to access the file

  • ODM_LIB - Oracle Disk Manager library is used to access the file

  • ASM_MANAGED - The file is managed and accessed though ASM

  • DNFS_LIB - The file is accessed through direct NFS library

RETRIES_ON_ERROR NUMBER Number of read retries on error