Database

turn on suggestions

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

Showing results for

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

a week ago

a week ago

How can we get list of columnar tables. As per my knowledge Columnar are NoPI tables, so in case we found skewness for them, how can we fix their skewness then?

Solved! Go to Solution.

Accepted Solutions

Highlighted

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

a week ago

a week ago

Hi,

NoPI tables are identified by DBC.TablesV.Tablekind = 'O'.

However, since TD 15.10, columnar tables can have either a Primary AMP index or a regular PI.

To identify CP tables then try this:

SEL * FROM dbc.partitioningconstraintsv WHERE columnpartitioninglevel > 0;

If you're on TD 15.10 or higher then specifying a PA or PI for those tables will help fix skew - just like a PI does for regular tables.

HTH

Dave

Ward Analytics Ltd - information in motion

www: http://www.ward-analytics.com

www: http://www.ward-analytics.com

1 ACCEPTED SOLUTION

4 REPLIES

Highlighted

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

a week ago

a week ago

Hi,

NoPI tables are identified by DBC.TablesV.Tablekind = 'O'.

However, since TD 15.10, columnar tables can have either a Primary AMP index or a regular PI.

To identify CP tables then try this:

SEL * FROM dbc.partitioningconstraintsv WHERE columnpartitioninglevel > 0;

If you're on TD 15.10 or higher then specifying a PA or PI for those tables will help fix skew - just like a PI does for regular tables.

HTH

Dave

Ward Analytics Ltd - information in motion

www: http://www.ward-analytics.com

www: http://www.ward-analytics.com

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

a week ago

a week ago

Thanks a lot Dave.

We have TD15.10 and the only Columnar table on our system is a NoPI. Its not highly skewed at the moment.

But, what do u suggest if it gets skewed, should we fix it like we fix any NoPI table (re-inserting data in NoPI table using HASH BY RANDOM)?

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

a week ago

a week ago

Hi Mobeen,

You could try that or use my suggestion from above "If you're on TD 15.10 or higher then specifying a PA or PI for those tables will help fix skew - just like a PI does for regular tables."

Cheers,

Dave

Ward Analytics Ltd - information in motion

www: http://www.ward-analytics.com

www: http://www.ward-analytics.com

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

a week ago

a week ago

Thanks a lot for all the information Dave.