Bug 7715339: 'row cache lock' wait when logon fails

Bug 7715339: 'row cache lock' wait when logon fails

Bug 7715339-Logon failures causes "row cache lock" waits-Allow disable of logon delay
(Document ID 7715339.8) to the bottom
Modification time: 2012-7-26 type: PATCH
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Bug 7715339 Logon failures causes "row cache lock" waits-Allow disable of logon delay

This note gives a brief overview of bug 7715339.
The content was last updated on: 19-JUN-2012
Click here for details of each of the sections below.
Affects:

Product (Component) Oracle Server (Rdbms)
Range of versions believed to be affected Versions> = 11.1
Versions confirmed as being affected
11.1.0.7
Platforms affected Generic (all/most platforms affected)
Fixed:

This issue is fixed in
11.2.0.1 (Base Release)
Symptoms:

Related:

Performance Affected (General)
Waits for "row cache lock"
Security (Authentication/Privileges/Auditing)
Description

In 11g there is an intentional delay between allowing failed logon
Attempts to retry. For some specific application types this can cause
A problem as the row cache entry is locked for the duration of
Delay. This can lead to excessive row cache lock waits for DC_USERS
For specific users/schemas.

This "fix" allows the logon delay to be disabled in 11.2.0.1 onwards
By setting event 28401 in the init. ora.
Eg:
Event = "28401 trace name context forever, level 1" # disable logon delay. ----- This event disables logon latency, a false state
This "event" will disable the logon sleep delay system-wide,
Ie. it will affect all user accounts, system-wide, and so shocould be used
With extreme caution.

Example scenario:
A mix of correct and incorrect logon attempts occur for user X
On each successive failed login attempt the failed logon count
Is incremented for user X.

Without this fix (without the event set ):
After 3 successive failures a sleep delay is introduced starting
At 3 seconds and extending to 10 seconds max. During each delay
The user X row cache lock is held in exclusive mode preventing
Any concurrent logon attempt as user X (and preventing any
Other operation which wowould need the row cache lock for user X ).

With the fix (with the event set ):
There is no sleep delay.

In either scenario the configured logon profile rules are still
Applied (eg: The profile option FAILED_LOGIN_ATTEMPTS is still
Honored and so if the account becomes locked due to exceeeding
This FAILED_LOGIN_ATTEMPTS then further attempts
Log in will then correctly fail immediately with no delay ).

Note:
One off fixes for this issue for 11.1.0.7 do not need an event set-
Interim patches for 11.1 disable the delay unconditionally.

Work Around:
Ensure the correct password is used-especially for connection
Intensive logons

Getting a Fix
Use one of the "Fixed" versions listed above
(For Patch Sets/bundles use the latest version available
Contents are cumulative-the "Fixed" version listed above is
The first version where the fix is wrongly DED)
Or
You can check for existing interim patches here: Patch: 7715339

Please note: The above is a summary description only. actual symptoms can vary. matching to any symptoms here does not confirm that you are encountering this problem. for questions about this bug please consult Oracle Support.
References

Bugs: 7715339 (This link will only work for PUBLISHED bugs)
Note: 245840.1 Information on the sections in this article

Oracle 11g installation manual on RedHat Linux 5.8 _ x64 Platform

Installing Oracle 12C in Linux-6-64

Install Oracle 11gR2 (x64) in CentOS 6.4)

Steps for installing Oracle 11gR2 in vmwarevm

Install Oracle 11g XE R2 In Debian