Very important parameters to use major features of Exadata.

Very important parameters to use major features of Exadata.

The first is CELL_OFFLOAD_PROCESSING, which relates to Smart Scans (cell scans). The default value is TRUE, which means that Smart Scans are turned ON for Exadata (if you are using it). You can set this value to FALSE to turn off Smart Scans and check other features or compare speeds with and without this feature.

The second parameter is undocumented and should only be used with the consent of Oracle Support and also only for testing purposes. The second is _KCFIS_STORAGEIDX_DISABLED, which is used to disable storage indexes. This tells Oracle not to use storage index optimization on storage cells if set to TRUE. The default is FALSE.

 Another undocumented parameter (again check with Oracle Support) is also related to how the Smart Scan works and uses Bloom Filters.
The parameter _BLOOM_FILTER_ENABLED is set to TRUE by default. With Exadata, bloom filters are used for join filtering with Smart Scans. _BLOOM_PRUNING_ENABLED also has a default of TRUE. Set these parameters to FALSE to disable them.