Re: enqueue waits
- From: Jared Still <jkstill@xxxxxxxxx>
- To: raja4list@xxxxxxxxx
- Date: Tue, 2 Aug 2005 10:54:48 -0700
The enqueues (locks) are occurring because another session
has an incompatible lock mode.
A DELETE needs SX (sub exclusive lock) mode to perform the delete.
Any session holding a higher mode lock (S, SSX, X) will block this
operation.
Examine the DBA_LOCKS and DBA_WAITERS views to determine
which sessions are blocking.
A good explanation is found in MetaLink note 15476.1, along with
several scripts.
Also read the Concepts manual, as it goes into some detail on this.
Data Concurrency and Consistency:
http://download-west.oracle.com/docs/cd/B19306_01/server.102/b14220/consist.htm#g43931
HTH
Jared
On 8/2/05, raja rao <raja4list@xxxxxxxxx> wrote:
>
> Hi All,
> When i try to delete few rows (4 rows) from the table
> bom.cst_item_cost_details (oracle apps 11.5.9), i observed that the
> session is waitng on enqueues.
> (The above table is too big, it has 20 million records in it.)
> But could not get much info what is the child table on which it is
> serching.
> Can someone throw somelight how to understand and find the root cause of
> these enqueus.
> what even could help understand the root cause .
> Thanks,
> Raj
>
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--
Jared Still
Certifiable Oracle DBA and Part Time Perl Evangelist
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