An incremental load may modify a large number of pages within the table being loaded.
As a result, the pages are temporarily versioned within the main dbspace, until the transaction commits and a checkpoint can release the old versions. This versioning can be particularly prevalent if the incremental load follows a delete from the same table. The reason for this is that, by default, Sybase IQ reuses row IDs from deleted records.
To help reduce space usage from versioned pages, set the APPEND_LOAD option ON so that IQ appends new data to the end of the table. APPEND_LOAD is OFF by default.
The APPEND_LOAD option applies to LOAD, INSERT...SELECT, and INSERT...VALUES statements.