SAS Companion for the OS/390 Environment

Estimating the Size of a SAS Index

Under OS/390, you can use the following formula to obtain a rough estimate of the size of a simple index:

size=(unique) * (8 + length) * (1.15)

unique: is the number of unique values of the key variable.
8: is the number of bytes of overhead for each unique value in the index.
length: is the length of the key variable, in bytes.
1.15: is a multiplication factor for general index overhead.

Note: The result of this calculation will be in bytes. You can convert this value to tracks based on the capacity of your data storage device. [cautionend]

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