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Tera-Tom on Teradata Physical Implementation V12-V13 by Tera-Tom Coffing

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Chapter 5 – Secondary Indexes

“The afternoon knows what the morning never suspected.”

- Swedish Proverb

The secondary index knows what the full table scan never suspected. Secondary Indexes provide an alternate path to the data. So far we have learned that every table has one and only one Primary Index and we have learned that the Primary Index is much faster than the Full Table Scan. Secondary Indexes are not as fast as the Primary Index, but they can be pretty fast, and they can be much faster than a Full Table Scan.

There can be up to 32 Secondary Indexes on a table, but there is a price to pay. Every Secondary Index creates a Subtable on every AMP designed to point to the real Primary Index Row-ID. I will explain in full detail. You ...

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