16.20 - SPOOL - Teradata Database - Teradata Vantage NewSQL Engine

Number of bytes to be allowed for spool and volatile temporary tables in database_name. The default is the largest value that is not greater than the immediate owner spool space and that is a multiple of the number of AMPs on the system.

n

You can enter the number of bytes as an integer, decimal, or floating point value or as a constant expression whose evaluation determines the number of bytes. You can also enter the value using exponential notation. For example, you can write one thousand as either 1000 or 1E3.

n cannot exceed the spool space parameter in the profile of the creator. If no spool space is defined for that profile, then Teradata Database uses the spool space limit defined for the individual user-creator.

constant_expression

A constant expression is any SQL expression that does not make any column references. Specifying an appropriate constant expression for the SPOOL space size of a database enables Teradata Database to assign an optimal quantity of SPOOL that scales to the size of your system by allocating SPOOL space on a per AMP basis.

When you specify a SPOOL size based on a constant expression, the assigned size does not automatically scale if, for example, you add more AMPs to your system.

BYTES

Optional keyword that redundantly specifies the unit for the amount of space allowed.

SKEW

Keyword that you use to specify a skew limit for SPOOL 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

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+spoolskewlimit/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.

DEFAULT

Use the value of DBS Control DefaultSpoolSkewLimitPercent.

PERCENT

Optional keyword that you can include for readability to indicate that the constant_expression or DEFAULT keyword specifies a percentage of allowable skew.

Example: Creating a Database with a Spool Space Skew Limit

     CREATE DATABASE d1 AS 
       PERM = 1e9
       SPOOL = 1e9 SKEW = 20 PERCENT;