Temporal tables typically contain more rows than otherwise equivalent nontemporal tables. This is due to the way rows are automatically added to temporal tables as a result of most kinds of modifications. Furthermore, rows are never physically deleted from system-time or bitemporal tables, but persist in the tables indefinitely.
For these reasons, temporal tables grow faster than nontemporal tables, at a rate that depends on how frequently they are modified, and on the nature of those modifications.
The following tables show how temporal tables that have a system-time dimension can grow depending on the nature and frequency of table modifications. Valid-time tables are likely to experience less growth, because rows in valid-time tables can be physically deleted from the tables.
Use these examples to estimate annual growth of temporal tables for capacity planning.
Table and Row Size Calculation forms are available in Teradata Vantage™ - Database Design, B035-1094 for nontemporal tables.
- Sequenced modifications are typically historical in nature.
- To reflect conservative estimates, the table size increase calculation is based on the maximum number of rows that can be produced by each type of modification.