This section summarizes the benefits, best uses, and restrictions of row compression in Teradata Database.
Benefits of Row Compression
- Reduces storage space by storing a repeating column value set only once, while any non-repeating column values that belong to that set are stored as logical extensions of the base repeating set
- Assigned by default for hash indexes
- Like multivalue compression, no decompression is necessary to access row-compressed data values
- Has no effect on table header size
Best Use of Row Compression
- Hash and join indexes that have numerous column values that repeat across rows.
Restrictions and Limitations of Row Compression
- Only applies to hash and join indexes
- Must be explicitly specified in the CREATE JOIN INDEX request for a join index at the time the index is created
For more information, see “CREATE JOIN INDEX” in SQL Data Definition Language - Syntax and Examples, B035-1144.