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ezhilv 1 post Joined 10/07
04 Oct 2007
How effceint the Teradata is ?

Hi,In Organization, we are palnning to move to teradata enterprise datawarehouse. But all the datawarehouse products will work fine in the normal scenorios, how teradata behaves in the following scenorio, We have dimension which is having 10 M records and a helper table with 20 M records and fact with the 20 M records.When the reports hits the helper tables the it dies. The tables are properly indexed with the help of the DBA's. How does the Teradata behaves in this scenorio.thanks,Ezhilv

marcmc 112 posts Joined 12/05
10 Oct 2007

I cannot analyse this without DDL, data and the SQL Statements used.An explain plan would also help.You made need join indices on your tables for the report to be efficient.Also does yer explain plan show product joins?

MumtazHussain 1 post Joined 01/07
23 Oct 2007

Is teradata retrives records faster using a pk having number or declared at varchar. What impact will it create if tables are having composite PK, including combination of number, Date and Varchar2??

dnoeth 4628 posts Joined 11/04
23 Oct 2007

There's almost no difference between an Integer PI and a 100 byte multi-column VarChar PI, because Teradata uses hashing. Of course there's more overhead to calculate a hash value from 100 byte compared to 4 bytes, but this is negligible.For joins it's similar: first both hash values are compared (each 4 bytes just like an integer) and only if those are the same, then the columns are compared. Dieter


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