1.what is activity count? 2.what is skew factor? how it's working explain

Categories >> Software >> Data Warehouse >> Teradata
Suggest New Category

1.what is activity count?
2.what is skew factor?
how it's working explain brefily

Question Posted / nagarjuna

5 Answers
32815 Views
Satyam, I also Faced
E-Mail Answers

Answers were Sorted based on User's Feedback

1.what is activity count? 2.what is skew factor? how it's working explain brefily..

Answer / vinay sir(datawarehousing tech

ActivityCount:The number of rows processed in the previous
sql statement it defines.
EG: if there is a table party is having 14 rows then
SELECT * FROM PARTY;
.ACTIVITYCOUNT= 14

Skewfactor:
It tells the distribution of the rows.
-->If uniformly distributed(normal distribution) skew
factor is 0.
-->Skew factor is the reversal of Parallel efficiency.(if
skew factor is 10 then parallel effciency is 90).

There is aformula to identify the skewness.
Please find the below.
SELECT TableName,SUM(CurrentPerm) AS
CurrentPerm,SUM(PeakPerm) AS PeakPerm,(100 -
(AVG(CurrentPerm)/MAX(CurrentPerm)*100)) AS SkewFactor
FROM Dbc.TableSize
WHERE DataBaseName = 'VINAY'
GROUP BY 1 ORDER BY 1

Is This Answer Correct ?

13 Yes

2 No

1.what is activity count? 2.what is skew factor? how it's working explain brefily..

Answer / yuvaevergreen

1. >> activity count indicates the no of rows affected/processed by the last request(no of rows returned to bteq from teradata).
2. >> skewness refers to the distribution of rows on the amps.
>> If some AMPs are having more rows and some very less, then skewness would be high. This would affect the parallelism.

3. Following query gives the skewness for all tables.
SELECT ts.DatabaseName
,ts.TableName
,td.CreateTimeStamp AS Created
,td.LastAlterTimeStamp AS LastAltered
,td.AccessCount
,td.LastAccessTimeStamp AS LastAccess
,SUM(ts.CurrentPerm) AS CurrentPerm
,SUM(ts.PeakPerm) AS PeakPerm,
(100 - (AVG(ts.CurrentPerm)/MAX(ts.CurrentPerm)*100)) AS SkewFactor
FROM DBC.TableSize ts
JOIN DBC.Tables td
ON ts.DatabaseName = td.DatabaseName
AND ts.TableName = td.TableName
GROUP BY 1,2,3,4,5,6;

Is This Answer Correct ?

6 Yes

0 No

1.what is activity count? 2.what is skew factor? how it's working explain brefily..

Answer / tdguy

activity count - rows processed by sql.
skew factor - distribution of data over the amps.
when the distribution is highly skewed, the amp working may
be affected, which inturn affects parallelism.

Is This Answer Correct ?

3 Yes

0 No

1.what is activity count? 2.what is skew factor? how it's working explain brefily..

Answer / tdguy

Hi Anjum,
As far as I know, "FROM" option in "IMPORT" mload
command can be used to load specific no of records. I would
suggest to use FROM and THRU option to load.

Is This Answer Correct ?

1 Yes

0 No

1.what is activity count? 2.what is skew factor? how it's working explain brefily..

Answer / anjum

one question please....how do we load firsr five record
through mload?

Is This Answer Correct ?

0 Yes

0 No

Post New Answer