Estimating Administrative TEMP Space Requirements
Allocate the TEMP space required by the applications that support your enterprise to user SysAdmin.
Like PERM space, TEMP space is allocated from the available space of the owning user. Make an estimate of temporary space requirements.
The TEMPORARY=n clause in the CREATE DATABASE and CREATE USER statements permits you to define how many bytes are to be allocated to a database or user for creating global temporary tables. Note that temporary space is reserved prior to spool space for any user defined to have this attribute.
Disk usage for materialized global temporary tables is charged to the temporary space allocation of the user who referenced the table.
Global temporary tables also require a minimum of 512 bytes from the PERM space of the containing database or user. This space is used for the GTT table header.
If no temporary space is defined for a user, then the space allocated for any global temporary tables referenced by that user is set to the maximum temporary space allocated for the immediate owner.