Hi,
I would sample logical reads from v$segment_statistics while the query
is still runing. If you calculate the delta you should see which segment
keeps changing.
An other option is query v$active_session_history.
Regards
Lothar
On 25.04.2016 19:10, Jessica Mason wrote:
Hello List,
Last week, I was involved in a production issue, where a data load job, which normally takes few hours to complete, had been running for more than 48 hours. I tried to take the following systematic approach to identify the cause -
Step 1 - Identify the session and started profiling it. All the time, the session was on CPU.
Step 2 - To understand why the session was burning CPU, the v$sesstat view was queried and below were the top statistics that were changing :
43126075162624 logical read bytes from cache
240440566773 table scan rows gotten
2632208820 session logical reads
2632206511 consistent gets
2632206511 consistent gets from cache
2632205708 consistent gets from cache (fastpath)
Step 3 - Next, I wanted to know the object ( table/index) against which these logical IOs were happening so that I could focus on the operations, involving these objects, in the execution plan but didn't know which view to query.
The above information could have saved us lot to time to identify the cause ( in this case, an unique index was dropped and Oracle was doing FTS on a table which was referred 6 times in the query fetching million of records).
So, my questions to the list is that which v$ view should I have checked?
Or is there a better approach to troubleshoot such issues?
Thanks
JM
