15.00 - Special Considerations for NUSI Size Estimates - Teradata Database

Teradata Database Design

prodname
Teradata Database
vrm_release
15.00
category
User Guide
featnum
B035-1094-015K

Special Considerations for NUSI Size Estimates

The number of AMPs in the configuration are an important factor in estimating the total size of any NUSIs defined on a base table, as summarized in the following table:.

 

IF the number of AMPS is …

THEN at least …

AND the result is that …

less than the number of rows per value

one row from each NUSI value is probably distributed to each AMP.

  • Every AMP has every value.
  • Every AMP has a subtable row for every value.
  • greater than the number of rows per value

    some AMPs are missing some NUSI values.

  • Not every AMP has every value.
  • Not every AMP has a subtable row for every value.