Re: IO_CELL_OFFLOAD_RETURNED_BYTES stats

The io_cell_offload_eligible_bytes column reports the bytes of data that qualify for offload. This is the volume of data that can be offloaded to the storage cells during query execution. The io_cell_offload_returned_bytes column reports the number of bytes returned by the regular I/O path. These are the bytes that were not offloaded to the
cells.


 
David Fitzjarrell
Primary author, "Oracle Exadata Survival Guide"

On Friday, April 25, 2014 9:39 AM, Ls Cheng <exriscer_at_gmail.com> wrote:
 
Hi


I am check a query statistics in Exadata and I noticed that v$sql.IO_CELL_OFFLOAD_ELIGIBLE_BYTES is cero but IO_CELL_OFFLOAD_RETURNED_BYTES has a pretty high value.


How can this possible?

select
executions,
disk_reads*16384/(1024*1024) PHY_MB,
IO_CELL_OFFLOAD_ELIGIBLE_BYTES/1024/1024 as "OFFLOADED_MB",
IO_CELL_OFFLOAD_RETURNED_BYTES/1024/1024 as "OFFLOAD_RT_MB",
IO_INTERCONNECT_BYTES/1024/1024 as "ICONNECT_MB",
PHYSICAL_READ_REQUESTS      ,
PHYSICAL_READ_BYTES/1024/1024 PHY_R_MB         ,
PHYSICAL_WRITE_REQUESTS     ,
PHYSICAL_WRITE_BYTES/1024/1024 PHY_W_MB
from v$sql
where sql_id = '4j92kqhrpcpr6'

EXECUTIONS     PHY_MB OFFLOADED_MB OFFLOAD_RT_MB ICONNECT_MB PHYSICAL_READ_REQUESTS   PHY_R_MB PHYSICAL_WRITE_REQUESTS   PHY_W_MB
---------- ---------- ------------ ------------- ----------- ---------------------- ---------- ----------------------- ----------
         1 130755.328            0    259544.156  520041.828                2801860 130598.375                  641580 129899.297


Thanks

--
http://www.freelists.org/webpage/oracle-l