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Teradata - How Teradata can accesses data ?

asked vishnoiprem August 17, 2014 05:08 AM  

How Teradata can accesses data ?


1 Answers

answered By vishnoiprem   0  
  • Primary Index (fastest)
  • Secondary Index (second fastest way)
  • Full Table Scan (slowest way)

Primary Index (fastest) - When ever a Primary Index is utilized in the SQL
WHERE Clause the PE will be able to use the Primary Index to get the data with a one-
AMP operation.

Secondary Index (next fastest) - If the Primary Index is not utilized sometimes
Teradata can utilize a secondary index. It is not as fast as the Primary Index, but it is
much faster than a full table scan.

Full Table Scan (FTS) (Slowest)
Teradata handles full table scans brilliantly because Teradata accesses each data row only
once because of the parallel processing. Full Table Scans are a way to access Teradata
without using an index. Each data block per table is read only once.
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