Expert Oracle Exadata - Parent Directory

CHAPTER 5 EXADATA SMART FLASH CACHECellCLI> list flashcache detailname:cellDisk:creationTime:degradedCelldisks:effectiveCacheSize:id:size:status:cell03_FLASHCACHEFD_01_cell03,FD_00_cell032010-11-09T15:29:28-06:0040Gad56aa9d-0de4-4713-85f2-197134523ebb40GnormalOnce again, using cellcli to manage storage including flash cache is covered in more detail inChapter 8, but this section should give you a basic understanding of how the flash cache is created.Controlling ESFC UsageGenerally speaking, objects will be cached in the ESFC based on the storage software’s automaticcaching policy. However, you can override the automatic policy for individual database objects by usingthe CELL_FLASH_CACHE storage clause attribute. The attribute has three valid values:NONE: Never cache this object.DEFAULT: The Automatic caching mechanism is in effect. This is the defaultvalue.KEEP: The object should be given preferential status. Note that this designationalso changes the default behavior of Smart Scans, allowing them to read fromboth the cache and disk.You can specify the storage clause when an object is created. Some options of the storage clause canbe modified using the ALTER command as well. Here’s an example of changing the CELL_FLASH_CACHEstorage clause using the ALTER command.alter table kso.skew storage (cell_flash_cache keep);You can also see whether objects have been designated for more aggressive caching by looking atthe cell_flash_cache column of dba_tables or dba_indexes:SYS@EXDB1> @esfc_keep_tablesSYS@EXDB1> select owner, table_name, status, last_analyzed,2 num_rows, blocks, degree, cell_flash_cache3 from dba_tables4 where cell_flash_cache like nvl('&cell_flash_cache','KEEP')5 /Enter value for cell_flash_cache:OWNER TABLE_NAME STATUS LAST_ANAL NUM_ROWS BLOCKS DEGREE CELL_FLASH_CACHE----- ---------- ------ --------- --------- ------- ------ ----------------KSO SKEW VALID 18-SEP-10 32000004 162294 1 KEEPKSO SKEW3 VALID 14-OCT-10 384000048 1949727 1 KEEP134