Expert Oracle Exadata - Parent Directory

CHAPTER 2 OFFLOADING / SMART SCANCELL_OFFLOAD_DECRYPTION parameter controls this behavior, and that as it does with the hiddenparameter _CELL_OFFLOAD_HYBRIDCOLUMNAR, setting the parameter to a value of FALSE completely disablesSmart Scans on encrypted data, which also disables decryption at the storage layer.Virtual ColumnsVirtual columns provide the ability to define pseudo-columns that can be calculated from other columnsin a table, without actually storing the calculated value. Virtual columns may be used as partition keys,used in constraints, or indexed. Column level statistics can also be gathered on them. Since the values ofvirtual columns are not actually stored, they must be calculated on the fly when they are accessed. Thesecalculations can be offloaded when access is via Smart Scans.SYS@SANDBOX1> alter table kso.temp_skew add col1_plus_pk as (col1+pk_col);Table altered.SYS@SANDBOX1> select col1_plus_pk from kso.temp_skew where rownum < 10;COL1_PLUS_PK------------2799826027998258279982562799825427998252279982502799824827998246279982449 rows selected.SYS@SANDBOX1> select count(*) from kso.temp_skew where col1_plus_pk=27998244;COUNT(*)----------2SYS@SANDBOX> @fsx4Enter value for sql_text: select count(*) from kso.temp_skew where col1_plus_pk=27998244Enter value for sql_id:SQL_ID CHILD OFFLOAD AVG_ETIME IO_SAVED_% SQL_TEXT------------- ------ ------- ------------- ---------- --------------------35tqjjq5vzg4b 0 Yes 1.14 99.99 select count(*) from1 row selected.SYS@SANDBOX1> @dplanEnter value for sql_id: 35tqjjq5vzg4b41