Re: How to simulate/generate the wait event "enq: IV - contention"

From: Andy Sayer <>
Date: Sat, 11 May 2019 15:45:29 +0100
Message-ID: <>

Hi Kunwar,

IMO that is a backwards way of tackling the problem. You should look at everything you can about the waiting when it actually happened - not try to replicate similar symptoms and fix those. If diagnostics pack licence has been purchased you will have a goldmine if information you can look at in gv$active_session_history (or the dba_hist version). Have a look at what was blocked and when, what were they trying to execute? What were all the parameters of the wait? What was the blocker doing? Remember you will have to look over all instances.

This wait event is mainly about syncing object invalidations between instances. So look at what DDL occurred around the time of the event (look at dba_objects.last_ddl_time for clues, otherwise you might get lucky with ASH - but you’ll only be able to see the command type rather than the SQL for most DDL). If DDL is logged, then check there.

Hope this helps,

On Sat, 11 May 2019 at 15:04, kunwar singh <> wrote:

> Hi Listers,
> I have a strange issue in one of accounts that my company supports.
> This wait coming daily at sporadically different times. It lasts only for
> few seconds, but it creates havoc for application job at that moment.
> How do we troubleshoot this apart from going to MOS.
> I would like to go deep into it , so is there a way/testcase i can
> reproduce the this wait event and then scan though all data dictionary
> /10046/other dumps in order to find the root cause and fix for it.
> Once i am able to reproduce this wait, IMO , it will get easier to
> troubleshoot it.
> --
> Cheers,
> Kunwar

Received on Sat May 11 2019 - 16:45:29 CEST

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