Re: IO_CELL_OFFLOAD_RETURNED_BYTES stats
- From: "David Fitzjarrell" <oratune@xxxxxxxxx> (Redacted sender "oratune@xxxxxxxxx" for DMARC)
- To: "exriscer@xxxxxxxxx" <exriscer@xxxxxxxxx>, Oracle Mailinglist <oracle-l@xxxxxxxxxxxxx>
- Date: Fri, 25 Apr 2014 09:11:26 -0700 (PDT)
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@xxxxxxxxx> 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
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