Having an inventory of typically used and business critical statements as
well as their execution plans and resource usage might be the kind of thing
to have around when response time issues occur.
Knowing the before part makes it a whole lot easier to diff.
Paul
On Aug 25, 2017 1:18 PM, "Sanjay Mishra" <dmarc-noreply@xxxxxxxxxxxxx>
wrote:
Thanks Cary. After making the required parameter change, application query
is back to normal. Will keep the suggested command for future use.
Rgd
Sanjay
On Thursday, August 24, 2017 2:57 PM, Cary Millsap <
cary.millsap@xxxxxxxxxxxx> wrote:
exec dbms_monitor.session_trace_enable(:sid,:serial)
...where :sid and :serial are the session_id and serial# of the Oracle
session you're curious about. The resulting trace file will show you all
the database calls and system calls that the session has executed. If
you're curious about your trace file, feel free to send it to me, and I'll
be glad to have a look.
Cary Millsap
Method R Corporation
Author of *Optimizing Oracle Performance <http://amzn.to/OM0q75>* and *The
Method R Guide to Mastering Oracle Trace Data, 2nd edition
<http://amzn.to/1U7q8X1>*
On Fri, Aug 18, 2017 at 2:49 PM, Sanjay Mishra <dmarc-noreply@xxxxxxxxxxxxx>
wrote:
After going thru patch details with Oracle it was found patch was doing the
following and so until got downtime to test patch thru all dev/test, the
following changes at database level resolve the issue
_optimizer_dsdir_usage_ control=0 -- disable use of directives
_sql_plan_directive_mgmt_ control=0 -- disable creation of directives
Tx for all suggestion and updates
Sanjay
On Friday, August 18, 2017 11:41 AM, Sanjay Mishra <
dmarc-noreply@xxxxxxxxxxxxx> wrote:
Jonathan
Thanks for your input. After having long session with Oracle Support
yesterday where SQL plan management and other options tried to stick with
one of the good execution but issue remains and finally Oracle provided
that it is due to bug and need to apply Patch 16470650
Bug 16470650
<https://support.oracle.com/epmos/faces/BugDisplay?id=16470650&parent=SrDetailText&sourceId=3-15564872561>
- Plans missing after loading from AWR to a SQL Tuning Set ( Doc ID
16470650.8
<https://support.oracle.com/epmos/faces/DocumentDisplay?parent=SrDetailText&sourceId=3-15564872561&id=16470650.8>
)
Working to get downtime to apply patch and will try the SQL again.
Tx
Sanjay
On Friday, August 18, 2017 2:37 AM, Jonathan Lewis <
jonathan@xxxxxxxxxxxxxxxxxx> wrote:
If it's taking a lot of CPU it's not hanging.
The most likely explanation - in the absence of any detailed information -
is that the query has changed it's execution path.
If the select is taking seconds while the insert is taking hours this may
mean the insert path is not allowed to take the access path of the select
statement (e.g. it's a distributed query which is allowed to use a
"driving_site (remote)" strategy while the insert has to drive off the
local site).
Alternatively the query started at a point in time when it had to do a huge
amount of read-consistency work, but the query doesn't have to do any
because it started at a much later point in time. (This one is a little
unlikely given the difference in scale, but a technical possibility).
Are your licensed to use the AWR, or have you installed Statspack. If the
insert has taken hours then its execution plan will have been captured in
AWR and you can check the plan and compare it with the "seconds" query.
You could query the dba_hist_active_sess_history to see where the insert
spent most of it's time (Randolf Geist has some excellent "XPLAN_ASH"
material to do this for you, but essentially it means pulling ASH rows for
the SQL_ID and picking out the plan operation details.
Regards
Jonathan Lewis
______________________________ __________
From: oracle-l-bounce@xxxxxxxxxxxxx <oracle-l-bounce@xxxxxxxxxxxxx > on
behalf of Sanjay Mishra <dmarc-noreply@xxxxxxxxxxxxx>
Sent: 18 August 2017 04:20
To: Oracle-L Freelists
Subject: Insert statement hanging
Hi
I had insert statement which is selecting database from 3-4 table and
hanging for several hours. Some main points are
- The Target Table where insert is going is empty table
- Select statement as itself is working geting 10K records in few sec
- Tried to create new table to insert but still not worked
- Insert session is showing very high wait on CPU and taking big CPU time
- Bouncing database and running insert worked first few min but as App is
started , it is again hanged and never complete
Opened Oracle SR now but they ask for Trace analyzer and so want to check
experts as what can be other thing to check. This was working fine and
suddenly started in last few days where no patching on Oracle/OS or major
changes to involved table are done.
Environment is Linux with Non-RAC using ASM as storage and Oracle
12c(12.1.0.2)
TIA
Sanjay
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