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Static Hash Screen

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

[hash]

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 LNGTH

The maximum and average lengths of the overflow chains, 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.