General

turn on suggestions

Auto-suggest helps you quickly narrow down your search results by suggesting possible matches as you type.

Showing results for

- Subscribe to RSS Feed
- Mark Topic as New
- Mark Topic as Read
- Float this Topic for Current User
- Bookmark
- Subscribe
- Printer Friendly Page

- Mark as New
- Bookmark
- Subscribe
- Subscribe to RSS Feed
- Get Direct Link
- Email to a Friend
- Report Inappropriate Content

11-20-2016
06:29 AM

11-20-2016
06:29 AM

I am trying to get the wasted space for each table and each database level due to skewness in teradata . I found below 2 statements in our forum. I am not able to understand the things.

Could some one please help.

Statement 1:

SyntaxEditor Code Snippet

COUNT(*)*(MAX(CurrentPerm)-AVG(CurrentPerm))/(1024**3) AS WastedSpace,

Statement 2:

SyntaxEditor Code Snippet

(MAX(CurrentPerm) * (HASHAMP()+1))/(1024**3) AS wastedStorage

Both are giving different result sets. which one will be the rright choice to get wasted space.

Solved! Go to Solution.

Accepted Solutions

- Mark as New
- Bookmark
- Subscribe
- Subscribe to RSS Feed
- Get Direct Link
- Email to a Friend
- Report Inappropriate Content

11-22-2016
03:08 PM

11-22-2016
03:08 PM

For these queries, both COUNT(*) and (HASHAMP()+1) return the total number of AMPs on your system.

Statement 2 is calculating what you might call the "effective space": (Number of AMPs)*(max space per AMP) - but not all of this space is "wasted".

Statement 1 is a correct way to calculate "wasted space": (Number of AMPs)*(max space per AMP - average space per AMP)

An alternative that gets the same answer would be (Number of AMPs)*(max space per AMP) - sum of space on all AMPs

1 ACCEPTED SOLUTION

2 REPLIES

- Mark as New
- Bookmark
- Subscribe
- Subscribe to RSS Feed
- Get Direct Link
- Email to a Friend
- Report Inappropriate Content

11-22-2016
03:08 PM

11-22-2016
03:08 PM

For these queries, both COUNT(*) and (HASHAMP()+1) return the total number of AMPs on your system.

Statement 2 is calculating what you might call the "effective space": (Number of AMPs)*(max space per AMP) - but not all of this space is "wasted".

Statement 1 is a correct way to calculate "wasted space": (Number of AMPs)*(max space per AMP - average space per AMP)

An alternative that gets the same answer would be (Number of AMPs)*(max space per AMP) - sum of space on all AMPs

- Mark as New
- Bookmark
- Subscribe
- Subscribe to RSS Feed
- Get Direct Link
- Email to a Friend
- Report Inappropriate Content

12-04-2016
10:39 PM

12-04-2016
10:39 PM

Thanks Fred.

Copyright © 2004-2015 Teradata Corporation. Your use of this Teradata website is governed by the Privacy Policy and the Terms of Use, including your rights to materials on this website, the rights you grant to your submissions to this website, and your responsibilities regarding your conduct on this website.

The Privacy Policy and Terms of Use for this Teradata website changed effective September 8, 2016.