Oracle Server Manager User's Guide

The File I/O Monitor

The File I/O Monitor contains one row for each file in the database and summarizes the read and write activity for each file. Only Oracle files are shown in the File I/O Monitor.

The following figure illustrates the left-most columns of the File I/O Monitor.

Figure 11 - 3. File I/O Monitor

The File I/O Monitor is described below:

Datafile Name of the database file.
Request Reads/s Number of physical reads per second since the last sample.
Request Writes/s Number of physical writes per second since the last sample.
Batch Blks/rd Number of physical blocks per read since the last sample.
Batch Blks/wt Number of physical blocks per write since the last sample.
Resp Time ms/rd Time per read, if TIMED_STATISTICS is TRUE.
Resp Time ms/wt Time per write, if TIMED_STATISTICS is TRUE.

Attention: Statistics related to time are not collected unless the parameter TIMED_STATISTICS is set to TRUE. For information about setting parameters, see the Oracle7 Server Administrator's Guide.

Filters

The following filter is available in the File I/O Monitor:

Datafile Filter for the name of the database file. Monitor displays information for files whose names match the Datafile filter.

SQL Worksheet Equivalent

To start the File I/O Monitor from a SQL Worksheet, you can use the following Server Manager commands:

	MONITOR FILEI/O

	MONITOR FILE

Required Views

To use the File I/O Monitor, you must have access to:

V$DBFILE

V$FILESTAT

Interpreting File I/O Statistics

If the values of Request Reads or Request Writes are high for all files on a given drive, you should consider restructuring your database to allocate database files and tablespaces across additional disk drives.

The product of Request Writes/s and Batch Blks/rd is the amount of data written to the file per second. If this value is high relative to the capacity of the corresponding disk, then you should consider changing the disk to one with a higher transfer rate.

When an index is generated or a SELECT statement is issued, a temporary sort file may be created. Look for excessive I/O to such files. Consider increasing the parameter SORT_AREA_SIZE or assigning different temporary tablespaces to different groups of users. For information about setting parameters, see the Oracle7 Server Administrator's Guide.

Datafile	Name of the database file.
Request Reads/s	Number of physical reads per second since the last sample.
Request Writes/s	Number of physical writes per second since the last sample.
Batch Blks/rd	Number of physical blocks per read since the last sample.
Batch Blks/wt	Number of physical blocks per write since the last sample.
Resp Time ms/rd	Time per read, if TIMED_STATISTICS is TRUE.
Resp Time ms/wt	Time per write, if TIMED_STATISTICS is TRUE.