1. Database Reference
  2. Dynamic Performance Views
  3. Dynamic Performance (V$) Views: V$IM_COLUMN_LEVEL to V$RULE_SET_AGGREGATE_STATS
  4. V$IOSTAT_FILE

8.18 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

NUMBER

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 - Operating 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

CON_ID

NUMBER

The ID of the container to which the data pertains. Possible values include:

  • 0: This value is used for rows containing data that pertain to the entire CDB. This value is also used for rows in non-CDBs.

  • 1: This value is used for rows containing data that pertain to only the root

  • n: Where n is the applicable container ID for the rows containing data