This screen displays comparative information for all logical
areas of a particular type, on a single screen.
By default, the screen displays the four most useful statistic
fields for the respective logical area type. However, you may
configure both the statistic fields displayed as well as the type
of statistic information displayed.
The "system" logical area information can be filtered from the
display, which will result in application logical areas being
displayed only.
There is no way to "mix and match" different logical areas on the
same screen display. This is impossible because of the different
statistic information collected for different logical area types.
It is possible to zoom on a specific logical area and display its
relevant statistic information. This drill-down capability makes
the "Logical Area Overview" an extremely useful analytical tool
for identifying performance bottlenecks or potential problems.
This screen is not available if the /NOLOGICAL_AREA qualifier is
specified, or if the INPUT qualifier is specified.
This screen displays the following fields:
o Logical Area Name -This column displays the name of the
logical area, followed by a period ".", followed by the name
of the physical area (storage area) in which the logical area
partition resides.
A maximum of 20 characters is displayed when the screen width
is 80 columns, which typically results in the storage area
name being partially truncated. To display the entire storage
area name, it may be necessary to zoom on the logical area
using the Zoom on-screen menu option. Alternately, a screen
width of more than 100 columns can be used to display the
entire area name.
For performance reasons, the logical area names are not sorted
in any particular order by default. You can configure the
screen to display the logical areas in alphabetical order.
Each logical area displayed represents a single partition of
that logical area. There is no method available to display the
logical areas aggregate statistic information.
o Statistic Field #1 - This column displays a user-selectable
statistic field appropriate for a hashed index logical area.
The default statistic field is "hash index fetched."
o Statistic Field #2 - This column displays a user-selectable
statistic field appropriate for a hashed index logical area.
The default statistic field is "hash insertion."
o Statistic Field #3 - This column displays a user-selectable
statistic field appropriate for a hashed index logical area.
The default statistic field is "hash deletion."
o Statistic Field #4 - This column displays a user-selectable
statistic field appropriate for a hashed index logical area.
The default statistic field is "pages discarded."
o Statistic Type - This column identifies the "type" of
statistic information being displayed. The following types
are available:
o CurTot - This column indicates the total number of
occurrences of the statistic since the database was opened
or the statistic collection information was reset; you can
reset this information using the "Reset" on-screen menu
option.
o CurRate - This column indicates the current occurrence-
per-second rate of the statistic during the last sample
interval (screen refresh); you can change the sample
interval using the "Set_rate" on-screen menu option.
o MaxRate - This column indicates the maximum occurrence-per-
second rate of the statistic since the RMU Show Statistic
utility was started or the statistic collection information
was reset; you can reset this information using the "Reset"
on-screen menu option.
o AvgRate - This column indicates the average occurrence-per-
second rate of the statistic since the database was opened
or the statistic collection information was reset; you can
reset this information using the "Reset" on-screen menu
option.
o PerTrans - This column indicates the transaction average
of the total-count column and the total number of completed
transactions.
Note the following:
o The "system" logical areas can be filtered from the "Logical
Area Overview" screen by selecting the "Display application
logical areas" option of the "Tools" menu. System logical
areas can be included on the screen by selecting the "Display
all logical areas" option of the "Tools" menu. Note that these
options are not available using the "Config" on-screen menu
option.
o The "Logical Area Overview" screen can also be configured to
display application logical areas only (no "system" logical
areas) using the configuration variable SYSTEM_LOGICAL_AREAS
with the keyword FALSE. Specifying the configuration variable
with the keyword TRUE, the default, will display all logical
areas, including "system" logical areas.
o The "Logical Area Overview" screen statistic type can be
specified using the configuration variable LOGICAL_OVERVIEW_
STAT with one of the following keywords: CUR_TOTAL, CUR_RATE,
MAX_RATE, AVG_RATE or PER_TRANS.
o The "Logical Area Overview" screen logical area type can be
specified using the configuration variable LOGICAL_OVERVIEW_
TYPE with one of the following keywords: TABLE, BTREE, HASH or
BLOB.
o When selecting statistic fields for the various columns using
the "Config" on-screen menu option, no validation is performed
to eliminate duplicate selections. This means you can display
the same statistic field in one or more columns at the same
time, if you so desire.