bug 7715339 登录失败触发 ‘row cache lock’ 等待

Bug 7715339 - Logon failures causes "row cache lock" waits - Allow disable of logon delay


(文档 ID 7715339.8) 究竟部 

改动时间:2012-7-26类型:PATCH 

为此文档评级 通过电子邮件发送此文档的链接 在新窗体中打开文档 可打印页

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 To:

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 the

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.-----该事件会禁用登录延迟，一种假死的状态

This "event" will disable the logon sleep delay system-wide,

ie. it will affect all user accounts, system-wide, and so should 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 would 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

 honoured and so if the account becomes locked due to exceeeding

 this FAILED_LOGIN_ATTEMPTS then further attempts to

 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 as

  contents are cumulative - the "Fixed" version listed above is

  the first version where the fix is included)

 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

Bug:7715339 (This link will only work for PUBLISHED bugs)

Note:245840.1 Information on the sections in this article