enq: HW contention - Bug 9407198

enq: HW contention  occured at the top wait event as a result of multiple sessions insert data into the same table.  This event is the competition for high water mark lock.  Oracle Support confirmed that we were hitting a bug 9407198.  The bug's summary is below..

Bug 9407198  "LOG ERRORS INTO" can cause OERI[kcb***] or hang scenarios

 This note gives a brief overview of bug 9407198.
 The content was last updated on: 23-FEB-2011
 Click here for details of each of the sections below.

Affects:

Product (Component)	Oracle Server (Rdbms)
Range of versions believed to be affected	Versions BELOW 12.1
Versions confirmed as being affected	11.2.0.1 11.1.0.7
Platforms affected	Generic (all / most platforms affected)

Fixed:

This issue is fixed in

12.1 (Future Release)

Symptoms:	Related To:
Hang (Process Hang) Internal Error May Occur (ORA-600) ORA-1578 / ORA-1115 ORA-600 [kcbnew_2] ORA-600 [kcbgcur_9]	DBMS_ERRLOG

Description

"LOG ERRORS INTO" can cause various ORA-600 errors, typically 
beginning ORA-600 [kcb*], or hangs, if an ORA-1578 or ORA-1115
error occurs during processing of the SQL statement.

Workaround:
 Address the cause of the triggering error (ie: ORA-1578 or ORA-1115).
 or
 Do not use the error logging clause on SQL statements
 

Note: 
 This fix only addresses the scenario of ORA-1578 and 
 ORA-1115 causing a subsequent problem during error logging.
 See bug 9150510 for a similar issue if the triggering error
 is an ORA-3113 error.