oracle11gbug：修改問題

　　oracle g bug修改普通用戶密碼掛住所有客戶端均連接不上生產中斷分析

　　環境

　　Oracle RAC for IBM AIX 節點

　　一條簡單的修改用戶密碼SQL語句

　　alter user ** identified by ***;

　　竟然會掛住在那此時所有的客戶端架構短連接)均無法連接也是連接出不來也不報錯

　　此時做了個生成了個跟蹤文件如附件

　　後重啟了個節點數據庫後用了不到分鐘又出現所有客戶端無法連接數據庫

　　FYI:

　　相關BUG

　　Description

　　In g 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 onwards

　　by setting event in the initora

　　eg:

　　event= trace name context forever level # disable logon delay

　　This event will disable the logon sleep delay systemwide

　　ie it will affect all user accounts systemwide 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 successive failures a sleep delay is introduced starting

　　at seconds and extending to 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

　　Note:

　　One off fixes for this issue for do not need an event set

　　interim patches for 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)

　　You can check for existing interim patches here: Patch:

　　總結

　　alter system set event= TRACE NAME CONTEXT FOREVER: trace name context forever level scope=spfile;

　　這個event 仍是在g 中推薦設置的

　　後經過驗證確實是屬於g 錯誤密碼驗證延時功能所導致

From:http://tw.wingwit.com/Article/program/Oracle/201311/16662.html