IO Screen [ ALLBASE/SQL Performance and Monitoring Guidelines ] MPE/iX 5.0 Documentation
ALLBASE/SQL Performance and Monitoring Guidelines
IO Screen
This screen provides I/O information on the data and log buffer pools.
Click here to view figure.
To invoke the IO screen, use the i command from the IO subsystem or the
/i command from other subsystems.
When you issue the SET DBENVIRONMENT command, the counters on this screen
are set to zero.
Field Definitions
REFRESH The screen refresh rate, in seconds.
SESSIONS The number of DBEnvironment sessions.
per sec The scale used to identify the length of the inverse
video bars and the data in the CUR, AVG, and MAX
columns. In the example above, the MAX frequency of
BUFF ACCESS is 67 per 10.0 seconds.
BUFF ACCESS The number of page requests issued to the data buffer
pool.
DATA DISK RD The number of pages that are not in the data buffer pool
at request time. The operating system must fetch these
pages, either from the operating system buffer pool or
by a physical disk read.
DATA DISK WR The number of dirty pages from the data buffer pool that
were logically written to disk.
LOG BUFF WR The number of records written to the log buffer pool.
LOG DISK RD The number of log pages fetched from disk. Unless you
have used rollforward recovery, this value is zero. The
operating system performs a physical read only if the
log page is not found in the operating system buffer
pool.
LOG DISK WR The number of log pages written from the log buffer pool
to disk. The operating system performs a physical write
for each log buffer write.
CHECKPOINTS The number of checkpoints taken. Checkpoints are
performed automatically, when the nonarchive log becomes
full, or when you issue a CHECKPOINT command.
DATA BUFFER The percentage of pages that are not in the data buffer
MISS RATE pool at request time. The percentage is calculated as
follows:
DATA BUFFER MISS RATE = (DATA DISK RD / BUFF ACCESS) * 100
TOTAL DATA The number of data buffer pages configured. To change
BUFFER PAGES the number of data buffer pages, issue the START DBE
statement or the SQLUtil ALTDBE command.
TOTAL LOG The number of log buffer pages configured. To change
BUFFER PAGES the number of log buffer pages, issue the START DBE
statement or the SQLUtil ALTDBE command.
ARCHIVE MODE Either ON or OFF, to indicate archive
or nonarchive logging.
Display Conventions
The characters displayed in the horizontal bars have special meanings, as
explained in the following table.
Legend
----------------------------------------------------------------------------------------------
| | | |
| Symbol | Corresponding Number | Description |
| | | |
----------------------------------------------------------------------------------------------
| | | |
| ! | CUR | Represents activity that has |
| | | occurred during the most recent |
| | | refresh interval. |
| | | |
----------------------------------------------------------------------------------------------
| | | |
| * | AVG | Designates the average amount of |
| | | activity that has occurred since |
| | | SQLMON has been attached to the |
| | | DBEnvironment. |
| | | |
----------------------------------------------------------------------------------------------
| | | |
| $ | AVG and CUR | Indicates that the average value |
| | | and the value of the most recent |
| | | refresh interval are the same. |
| | | |
----------------------------------------------------------------------------------------------
| | | |
| Full bright inverse | MAX | Designates the maximum amount of |
| video | | activity that has occurred since |
| | | SQLMON has been attached to the |
| | | DBEnvironment. |
| | | |
----------------------------------------------------------------------------------------------
Related SET Commands
Use the SET REFRESH command to modify the refresh rate of the screen.
MPE/iX 5.0 Documentation
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