There are few limitations which we have on Fastload.
These limitations are necessary for Fastload to load data with the lightning fast speed into tables.
- NO SECONDARY INDEXES ARE ALLOWED ON TARGET TABLE – Fastload can load tables only with primary indexes defined on it. If we have a secondary index on the table then Fastload will not load that table. We get a error message if we load such type of table –
If secondary index exist already, we need to drop them.
After loading the table through Fastload we can easily recreate them on the table.
CREATE INDEX (Column-name/s) ON dbname.tablename —— > creates Non Unique Secondary Index
CREATE UNIQUE INDEX (Column-name/s) ON dbname.tablename —— > creates Unique Secondary Index
- NO REFERENTIAL INTEGRITY IS ALLOWED – Fastload cannot load data into tables that are defined with Referential Integrity (RI). This would require too much system checking to prevent referential constraints to a different table
- NO TRIGGERS ARE ALLOWED AT LOAD TIME – Fastload is much too focused on speed to pay attention to the needs of other tables, which is what Triggers are all about. Additionally, these require more than one AMP and more than one table. Fastload does one table only. Simply ALTER the Triggers to the DISABLED status prior to using Fastload.
- DUPLICATE ROWS ARE NOT SUPPORTED – Multiset tables are a table that allow duplicate rows — that is when the values in every column are identical. When Fastload finds duplicate rows, they are discarded. While Fastload can load data into a multi-set table, Fastload will not load duplicate rows into a multi-set table because Fastload discards duplicate rows
Related Post –Teradata Utilities : FASTLOAD – Part 1