What are the Considerations for EXADATA Smart Scan Cell Offloading?

In below mentioned situations the exadata predicate evaluation will not offloaded.
  • If you use more that 255 columns in the query
  • The object which belongs to the tablespace is not stored on the Exadata
  • If a virtual column is present on the query
  • Value of CELL_OFFLOAD_PROCESSING is set to FALSE
  • The table or table partition being used in query is small
  • A LOB or LONG column is being used in the query
  • The data is encrypted and cell-based decryption is disabled
  • Select on the flashback table is performed
  • A CREATE INDEX with NOSORT option
  • If the optimizer wants the scan to return the rows in ROWID order.
  • If the table is clustered one
  • If the table has row dependency enabled
  • If the table rowscn is being fetched
  • Optimizer decides not to use direct path reads

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