HP 3000 Manuals

ALLBASE/SQL Performance and Monitoring Guidelines

Static Hash Screen 

This screen provides information about the primary and overflow pages of
hashed tables.

	       Click here to view figure.
            

To invoke the Static Hash screen, use the h command from the Static
subsystem or the /st h command from other subsystems.

Field Definitions 

DBEFILESET       The name of the DBEFileSet.

                 The keyword DETACHED means that the DBEFileSet is
                 detached.  The keywords DETACHED DBEFILES mean that the
                 DBEFileSet is attached, but some of the DBEFiles within
                 it are detached.

OWNER.TABLE      The name of each hashed table in the DBEFileSet.

PRIMPAGES        The number of primary pages allocated for the hash
                 structure.  This value is equivalent to the PRIMPAGES
                 column of SYSTEM.HASH and is specified by the UNIQUE
                 HASH clause of the CREATE TABLE statement.

PRIMDATA         The number of primary pages that currently contain table
                 data.  This value is equivalent to the NPAGES column of
                 SYSTEM.HASH.

PRIMOVERF        The number of primary pages containing table data that
                 have overflow pages.  This value is equivalent to the
                 NOVERFLOW column of SYSTEM.HASH.

OVERPAGES        The number of overflow pages allocated for the hash
                 structure.

OVERFLOW CHAIN   The maximum and average lengths of the overflow chains,
LNGTH            displayed graphically.  The maximum length is
                 represented by full bright, inverse video bars.  The
                 average length is indicated by half bright, inverse
                 video bars and is delimited on the right with an
                 asterisk.

MAXOVERFLOW      The length of the longest overflow chain in the table.
                 This value is one less than the MAXLEN column of the
                 SYSTEM.HASH pseudotable, because MAXLEN includes the
                 primary page in the chain length.

AVGOVERFLOW      The average length of the overflow chains, calculated as
                 follows:

                      AVGOVERFLOW = round (OVERPAGES / PRIMOVERF)

Related SET Commands 

Use the SET DBEFILESET command to improve performance and to display only
those tables contained in a particular DBEFileSet.

MPE/iX 5.0 Documentation