Secondary index

Tools & Utilities

Secondary index

Hello everybody, I am very new to Teradata.Can anyone pls explain me in brief, in which situation we use Secondary index and why.

I really appreciate that.

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2 REPLIES
Enthusiast

Re: Secondary index

Hi,

You can use the secondary indexes in the following situations:

  1. To improve access of frequently accessed columns which can not be defined as PI.
  2. To enforce uniqueness using USI  (PrimaryKey, UNIQUE)
  3. To improve access to Range queries(NUSI over PPI tables)

But remember Secondary indexes cause a lot of overhead on system resources in terms of Disk space and IO. SI create a subtale that use diskspace and there is a maintainance overhead as well.

Khurram

Re: Secondary index

Thanks a lot Mr. Saeed, its helped me a lot. I appreciate your help.