Disk usage for a materialized global temporary table is charged to the temporary space allocation of the user who referenced the table. Temporary space is reserved prior to spool space for any user defined with this characteristic.
If default temporary space is not defined for a database, then the space allocated for any materialized global temporary tables created in that database is set to the maximum temporary space allocated for its immediate owner.
- Number of bytes to be allowed by default for creating global temporary tables by users within this database.
- Any SQL expression that does not make any column references. Specifying an appropriate constant expression for the TEMPORARY space size of a user enables Teradata Database to assign an optimal quantity of TEMPORARY space that scales to the size of your system by allocating TEMPORARY space on a per AMP basis.
- When you specify a TEMPORARY space size based on a constant expression, the assigned size does not automatically scale if, for example, you add more AMPs to your system.
- Optional keyword that redundantly specifies the unit for the amount of space allowed.
- Keyword that you use to specify a skew limit for TEMPORARY space. You can specify a skew limit percentage that allows the maximum AMP space usage to be above the per-AMP quota, that is, the system maximum space limit divided by the number of AMPs.
- Constant expression or constant from 0 through 10000. Specify a value from 1 to 9999 to indicate an AMP-level limit, which is the per-AMP quota * (1+tempskewlimit/100). Specify 0 to set space accounting to the per-AMP level, that is, no skew. A value of 10000 indicates unlimited skew, up to the system maximum space limit.
- Use the value of DBS Control DefaultTempSkewLimitPercent.
- Optional keyword that you can include for readability to indicate that the constant_expression or DEFAULT keyword specifies a percentage of allowable skew.
Example: Modifying a Database to Add a Temporary Space Skew Limit
MODIFY DATABASE d1 AS PERM = 1e9, TEMPORARY = 1e9 SKEW = 20 PERCENT;