SQL/MX 2.x Reference Manual (H06.04+)

SQL/MX File Attributes

HP NonStop SQL/MX Reference Manual—540440-003

8-3

AUDITCOMPRESS

The AUDITCOMPRESS file attribute controls whether TMF audit records for the file

are compressed. Compressed audit records omit unchanged columns from the before

and after images of updated rows. Uncompressed audit records allow you to read

complete rows in the audit trail but require more space.

You set the AUDITCOMPRESS attribute for a table with CREATE TABLE or ALTER

TABLE. You set the AUDITCOMPRESS attribute for an index with CREATE INDEX or

ALTER INDEX.

The table default is AUDITCOMPRESS. The index default is the table value at index

creation.

Considerations for AUDITCOMPRESS

Index Default

By default, the AUDITCOMPRESS attribute is automatically set for an index to match

that of the associated base table. If the AUDITCOMPRESS file attribute is changed on

the base table, that change is automatically propagated to the index.

Difference Between Compressed and Uncompressed Row

Images

Audit records of uncompressed files contain entire before and after images of changed

rows. Audit records of compressed files generally contain only changed columns and

columns of the clustering key. Other columns are occasionally included to improve

performance, such as when a single unchanged column physically occurs between

several changed columns.

AUDITCOMPRESS | NO AUDITCOMPRESS