This section summarizes the benefits, best uses, and restrictions of row header compression in Teradata Database.
Benefits of Row Header Compression
- Only applied to columns partition that have COLUMN format
- Reduces I/O overhead
- Automatically applied to column partitions with COLUMN format whether you specify AUTO COMPRESS or NO AUTO COMPRESS
Best Use of Row Header Compression
- Column partitions in COLUMN format that contain many column partition values per container
Restrictions and Limitations of Row Header Compression
- If only a few column partition values can be placed in a container because of their width, there can be an increase in the space needed for a column-partitioned object in COLUMN format compared to the object without column partitioning
In this case, ROW format might be a more appropriate choice
- If a combined partition contains only a few column partition values, there can be a very large increase in the space needed for a column-partitioned object compared to the same object defined without column partitioning
In this case, consider either altering the row partitioning to allow for more column partition values per combined partition, reducing the number of row partitions, or removing column partitioning altogether
- Over partitioning a table loses the advantages of row header compression