Purpose
Specifies conditions under which data blocks (DBs) for spool and volatile tables will be compressed by default.
Field Group
Compression
Valid Settings
Setting | Description |
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ALWAYS | The DBs of a new Spool table will be compressed. |
NEVER | The DBs of a new Spool table will not be compressed. The Ferret utility COMPRESS command will have no effect. |
IFNOTCACHED | The DBs of a new table will be compressed if they are not being cached. |
Default
NEVER
Changes Take Effect
After the DBS Control Record has been written.
Usage Notes
BLC enables data compression at the data block (DB) level of the Teradata Database file system. Compression reduces the amount of storage required for a given amount of data. The BlockLevelCompression field of DBS Control enables and disables BLC.
BLC can be enabled or disabled system-wide, or for various categories of tables. For Permanent data, these include subtables for primary, fallback, eligible LOB data, and join and hash indexes. Secondary indexes on primary rows are never compressed, but fallback copies of secondary indexes can be compressed to save space.
Spool includes Persistent Spool used for the Redrive feature.
Related Topics
For more information on... | See... |
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BlockLevelCompression field | BlockLevelCompression. |
COMPRESS and UNCOMPRESS commands | Ferret Utility (ferret). |