NOPI feature in Teradata 13.0

The purpose of teradata 13.0 feature that allows us to create table with no primary index is to improve performance of fastload. because there is no primary index for the rows of a NOPI table the rows are not hashed to an AMP based on their primary index.Instead , Teradata Database either hashes on the Query ID for a row, or it uses a different algorithm to assign the row to its home AMP once it reaches the AMP onto which it has been FastLoaded. The Teradata Database then generates a RowID for each row in a NoPI table by randomly selecting an arbitrary hash bucket that an AMP owns and using it to generate a RowID. Using a NoPI table as a staging table for such applications avoids the row redistribution and sorting required for primary-indexed staging tables. Another advantage of NoPI tables is that you can quickly load data into them and be finished with the acquisition phase of the utility operation, which frees client resources for other applications. LIMITATIONS : You cannot create a NoPI queue table. • You cannot create a NoPI error table. • You cannot create a NoPI table as a SET table. The default table type for NoPI tables in both Teradata and ANSI session modes is always MULTISET. • If neither PRIMARY INDEX (column_list) nor NO PRIMARY INDEX is specified explicitly in a CREATE TABLE request, then whether the table is created with or without a primary index generally depends on the setting of the DBS Control flag DisableNoPI • NoPI tables cannot specify a permanent journal. • NoPI tables cannot specify an identity column. • Hash indexes cannot be defined on NoPI tables because they inherit the primary index of their underlying base table, and NoPI tables have no primary index. • SQL UPDATE triggers cannot update a NoPI table. • SQL UPDATE and UPDATE (Upsert Form) requests cannot update a NoPI target table. SQL UPDATE and UPDATE (Upsert Form) requests can update a primary-indexed target table from a NoPI source table. • SQL MERGE requests cannot update or insert into a NoPI target table. SQL MERGE requests can update or insert into a primary-indexed target table from a NoPI source table. • You cannot load rows into a NoPI table using the MultiLoad utility.