SQL/MP Reference Manual

HP NonStop SQL/MP Reference Manual—523352-013

I-29

ISLACK File Attribute

ISLACK is a file attribute that specifies the minimum percentage of space to leave for

future insertions when loading index blocks. ISLACK applies only to key-sequenced

tables and to indexes.

The default is the value of the SLACK file attribute.

The default for SLACK is 15 percent.

percent

is an integer from 0 to 99 that specifies the percent of empty space to leave in

each index block during loading.

Considerations—ISLACK



ISLACK specifications are usually between 15 and 25 percent.



Specifying a larger-than-normal ISLACK value when a file is initially loaded, and

many more inserts are expected, can improve performance by reducing the

number of block splits required when inserts occur.



For a file expected to have little activity, you can save disk space by specifying a

smaller-than-normal ISLACK value.

ISLACK percent