Skew factor

Database

Skew factor

Waht is skew factor and how does one measure it? For eg, the skew factor of the Acctg system table is 7 whereas the factor for AccLogTbl is 23.

What do these signify?

varun
1 REPLY

Re: Skew factor

The skew factor tells you how unevenly a table is distributed across AMPs. A value of zero is "perfect". A value approaching 100 would indicate that all of the data is on one AMP.

You can get it as follows by table:

SELECT databasename
,tablename
,100 * (1 - (AVG(currentperm) / MAX(currentperm))) skew_factor
FROM dbc.tablesize
GROUP BY 1,2
ORDER BY 1,2;