15.00 - Capacity Planning for Temporal Tables - Teradata Database

Teradata Database Temporal Table Support

prodname
Teradata Database
vrm_release
15.00
category
Programming Reference
featnum
B035-1182-015K

Capacity Planning for Temporal Tables

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, under normal conditions, “deleted” rows are not truly physically deleted from temporal tables that have a transaction time dimension.

For the same reasons, temporal tables can grow faster than nontemporal tables, depending on how frequently they are modified, and on the nature of those modifications. Tables with transaction-time columns grow monotonically, never shrinking, because rows are never physically deleted from these tables.

The following tables show how temporal tables that have a transaction-time column 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 Database Design for nontemporal tables.

Note:  

  • 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.
  • Example : Lightly Modified Table

     

     

    Transaction-time Table

    Bitemporal Table

    Bitemporal Table

    Table Size Before Modifications (rows)

    100

    100

    100

    Modification Type

    Current

    Current

    Sequenced (historical)

    Modifications per Year (percent of rows)

    10% (0.19% weekly)

    10% (0.19% weekly)

    10% (0.19% weekly)

    Number of Additional Rows Produced per Modification

    1

    1 or 2

    1, 2, or 3

    Largest Table Size After Modifications (rows)

    110

    120

    130

    Annual Increase in Table Size

    10%

    20%

    30%

    Example : Moderately Modified Table

     

     

    Transaction-time Table

    Bitemporal Table

    Bitemporal Table

    Table Size Before Modifications (rows)

    100

    100

    100

    Modification Type

    Current

    Current

    Sequenced (historical)

    Modifications per Year (percent of rows)

    30% (0.58% weekly)

    30% (0.58% weekly)

    30% (0.58% weekly)

    Number of Additional Rows Produced per Modification

    1

    1 or 2

    1, 2, or 3

    Largest Table Size After Modifications (rows)

    130

    160

    190

    Annual Increase in Table Size

    30%

    60%

    90%

    Example : Heavily Modified Table

     

     

    Transaction-time Table

    Bitemporal Table

    Bitemporal Table

    Table Size Before Modifications (rows)

    100

    100

    100

    Modification Type

    Current

    Current

    Sequenced (historical)

    Modifications per Year (percent of rows)

    50% (0.96% weekly)

    50% (0.96% weekly)

    50% (0.96% weekly)

    Number of Additional Rows Produced per Modification

    1

    1 or 2

    1, 2, or 3

    Largest Table Size After Modifications (rows)

    150

    200

    250

    Annual Increase in Table Size

    50%

    100%

    150%