15.00 - Example Measurement 1 - Teradata Database

Teradata Database Design

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

Example Measurement 1

Table A and Table B both have 60 million 100-byte rows. An aggregate join index with two INTEGER columns and one SUM(INTEGER) column.

From these figures, the computed size of the aggregate join index is as follows:

 

FOR this type of join index …

THERE is one join index row …

non‑aggregate

for every matching row in the base table.

aggregate

per group of rows in the join of the base tables.

The permanent space specification is as follows:

 

Current Permanent Space (Bytes)

Peak Permanent Space (Bytes)

Maximum Permanent Space (Bytes)

2,041,595,904

2,041,595,904

0

Using these figures, you can compute a measured row size:

Because the measured and computed disk spaces are identical within a narrow confidence interval, it is safe to conclude that the disk space formula is accurate for an aggregate join index.