4.5 Briefly describe the screens in the static subsystem
Key points
- The DBEnvironment does not need to be active to obtain any screen in the
subsystem.
Menu
SQLMONITOR SUBSYSTEMS (and abbreviations):
OVERVIEW IO LOAD LOCK SAMPLEIO STATIC
/o /i /loa /loc /sa /st
CURRENT SUBSYSTEM SCREENS:
STATIC DBEFILE SIZE INDIRECT CLUSTER HASH
st d si i c h
Static screen
SQLMONITOR STATIC => st /* From the current subsystem */
SQLMONITOR OVERVIEW => /st /* From another subsystem */
This screen provides miscellaneous information about each DBEFileSet within
the DBEnvironment, including the names of all tables in the DBEFileSet, the
number of B-tree indexes and referential constraints (PCRs) that are defined
on each table, the implicit locking structure associated with each table (for
example, PUBLIC), and whether or not a table is actually a TurboIMAGE data set.
SQLMONITOR STATIC => help tune
1 DO NOT PUT USER-DEFINED OBJECTS IN THE SYSTEM DBEFILESET
Static dbefile screen
SQLMONITOR STATIC => d /* From the current subsystem */
SQLMONITOR OVERVIEW => /st d /* From another subsystem */
This screen provides information about the capacity and fullness of each
DBEFileSet existing in the DBEnvironment. The capacity and fullness of each
DBEFile contained within the DBEFileSet(s) is also provided. This information
can be used to determine whether or not space should be added to or removed
from the DBEnvironment.
In the above example, only one DBEFile has been added to the SYSTEM DBEFileset.
The maximum number of pages in the DBEFile is 5000 (each page is 4K). 143 of
those pages (or 3%) are "used" (in other words, these pages have data
on them).
SQLMONITOR STATIC => help tune
1 DROP EXTRA DBEFILES
Static size screen
SQLMONITOR STATIC => si /* From the current subsystem */
SQLMONITOR OVERVIEW => /st si /* From another subsystem */
This screen provides information about the size of tables, B-tree indexes,
and referential constraints (PCRs) contained within a DBEFileSet.
SQLMONITOR STATIC => help tune
1 DO NOT PUT USER-DEFINED OBJECTS IN THE SYSTEM DBEFILESET
2 PLACE LARGE (>1000 PAGES) TABLES IN THEIR OWN DBEFILESETS
3 GATHER SMALL TABLES INTO DBEFILESETS OF ABOUT 1000 OR LESS PAGES.
Static indirect screen
SQLMONITOR STATIC => i /* From the current subsystem */
SQLMONITOR OVERVIEW => /st i /* From another subsystem */
This screen provides information about the percentage of indirect rows that
exist in each table of a DBEFileSet. An indirect row is one that can only be
accessed by first fetching one page to obtain the address of the row, and then
fetching a second page to actually obtain the row data. Indirect rows increase
the amount of I/O that must be performed to obtain data.
This screen can be used to monitor the number of rows in TurboIMAGE data sets
(these rows should never be reported as indirect rows).
SQLMONITOR STATIC => help tune
1 UNLOAD/LOAD A TABLE TO REMOVE INDIRECT ROWS
Static cluster screen
SQLMONITOR STATIC => c /* From the current subsystem */
SQLMONITOR OVERVIEW => /st c /* From another subsystem */
This screen provides information about the clustering of B-tree indexes and
referential constraints (PCRs) contained within a DBEFileSet. Applications
which frequently access data in index order (which includes using an ORDER BY,
GROUP BY, DISTINCT, or UNION clause) will have better performance if the table
data is "clustered" (physically stored on disk in index order). Performance
is improved because I/O is minimized.
SQLMONITOR STATIC => help tune
1 UNLOAD/SORT/LOAD A TABLE TO RECLUSTER AN INDEX/CONSTRAINT
Static hash screen
SQLMONITOR STATIC => h /* From the current subsystem */
SQLMONITOR OVERVIEW => /st h /* From another subsystem */
The STATIC HASH screen provides information about the overflow chains
associated with hashed tables.
SQLMONITOR STATIC => help tune
1 UNLOAD/LOAD A HASHED TABLE TO REMOVE OVERFLOW PAGES
Page last updated on November 29, 1995
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