ORA-27123: unable to attach to shared memory segment

Hello,

Of late, in one of our test unix (Sun Solaris) boxes, a database user is trying to connect to the database, but getting an error “ORA-27123: unable to attach to shared memory segment” with permission denied issue.

Initially we thought that there might be an issue with SGA memory area or may be an issue with the shared memory segments and semaphores for the instance allocated. But later we found that the permission on ORACLE_HOME directory got changed accidentally with the full permission.

Here are our findings:

$ sqlplus testusr/password@testdb

SQL*Plus: Release 10.2.0.2.0 - Production on Tue Jan 27 20:53:44 2009

Copyright (c) 1982, 2005, Oracle. All Rights Reserved.

ERROR:
ORA-01034: ORACLE not available
ORA-27123: unable to attach to shared memory segment
SVR4 Error: 13: Permission denied 

As per Oracle Error Messages:

Error: ORA-27123: unable to attach to shared memory segment
Cause: shmat() call failed
Action: check permissions on segment, contact Oracle support

Check the oracle executable file permission.

$ cd $ORACLE_HOME/bin
$ ls -l oracle
-rwxrwxr-x 1 oracle dba 119582976 Feb 3 2008 oracle

Here the oracle file permission has -rwxrwxr-x i.e. 775, but this file must have the permission -rwsr-s- -x i.e. 6751

Change the permissions for oracle file.

$ cd $ORACLE_HOME/bin
$ chmod 6751 oracle
$ ls -l oracle
-rwsr-s--x 1 oracle dba 119582976 Feb 3 2008 oracle

After changing the permissions on oracle executable file, all the users are now able to connect to the database without any errors.

Note: For further information refer the Oracle Metalink Note ID: 1011995.6 Subject: COMMON ORACLE PERMISSION PROBLEMS ON UNIX.

Regards,
Sabdar Syed

Oracle Metalink Notes for Oracle Apps DBAs.

Dear Friends,

Here are the list of Oracle Metalink Notes, I do refer regularly. Moreover, these are very informative. So, I thought of sharing those note ids here with you.

Note: You have to have an account in Oracle Metalink to access notes.

Installation

Note: 452120.1 - How to locate the log files and troubleshoot RapidWiz for R12
Note: 329985.1 - How to locate the Rapid Wizard Installation log files for Oracle Applications 11.5.8 and higher
Note: 362135.1 - Configuring Oracle Applications Release 11i with Oracle10g Release 2 Real Application Clusters and Automatic Storage Management
Note: 312731.1 - Configuring Oracle Applications Release 11i with 10g RAC and 10g ASM
Note: 216550.1 - Oracle Applications Release 11i with Oracle9i Release 2 (9.2.0)
Note: 279956.1 - Oracle E-Business Suite Release 11i with 9i RAC: Installation and Configuration using AutoConfig
Note: 294932.1 - Recommendations to Install Oracle Applications 11i
Note: 403339.1 - Oracle 10gR2 Database Preparation Guidelines for an E-Business Suite Release 12.0.4 Upgrade
Note: 455398.1 - Using Oracle 11g Release 1 Real Application Clusters and Automatic Storage Management with Oracle E-Business Suite Release 11i
Note: 402311.1 - Oracle Applications Installation and Upgrade Notes Release 12 (12.0.4) for Microsoft Windows
Note: 405565.1 - Oracle Applications Release 12 Installation Guidelines

AD Utilities

Note: 178722.1 - How to Generate a Specific Form Through AD utility ADADMIN
Note: 109667.1 - What is AD Administration on APPS 11.0.x ?
Note: 112327.1 - How Does ADADMIN Know Which Forms Files To Regenerate?
Note: 136342.1 - How To Apply a Patch in a Multi-Server Environment
Note: 109666.1 - Release 10.7 to 11.0.3 : What is adpatch ?
Note: 152306.1 - How to Restart Failed AutoInstall Job
Note: 356878.1 - How to relink an Applications Installation of Release 11i and Release 12
Note: 218089.1 - Autoconfig FAQ
Note: 125922.1 - How To Find Oracle Application File Versions

Cloning

Note: 419475.1 - Removing Credentials from a Cloned EBS Production Database
Note: 398619.1 - Clone Oracle Applications 11i using Oracle Application Manager (OAM Clone)
Note: 230672.1 - Cloning Oracle Applications Release 11i with Rapid Clone
Note: 406982.1 - Cloning Oracle Applications Release 12 with Rapid Clone
Note: 364565.1 - Troubleshooting RapidClone issues with Oracle Applications 11i
Note: 603104.1 - Troubleshooting RapidClone issues with Oracle Applications R12
Note: 435550.1 - R12 Login issue on target after cloning
Note: 559518.1 - Cloning Oracle E-Business Suite Release 12 RAC-Enabled Systems with Rapid Clone
Note: 216664.1 - FAQ: Cloning Oracle Applications Release 11i

Patching

Note: 225165.1 - Patching Best Practices and Reducing Downtime
Note: 62418.1 - PATCHING/PATCHSET FREQUENTLY ASKED QUESTIONS
Note: 181665.1 - Release 11i Adpatch Basics
Note: 443761.1 - How to check if a certain Patch was applied to Oracle Applications instance?
Note: 231701.1 - How to Find Patching History (10.7, 11.0, 11i)
Note: 60766.1 - 11.0.x : Patch Installation Frequently Asked Questions
Note: 459156.1 - Oracle Applications Patching FAQ for Release 12
Note: 130608.1 - AdPatch Basics
Note::60766.1 - Patch Installation FAQ (Part 1)

Upgrade

Note: 461709.1 - Oracle E-Business Suite Upgrade Guide - Plan
Note: 293166.1 - Previous Versions of e-Business 11i Upgrade Assistant FAQ
Note: 224875.1 - Installation, Patching & Upgrade Frequently Asked Questions (FAQ's)
Note: 224814.1 - Installation, Patching & Upgrade Current Issues
Note: 225088.1 - Installation, Patching & Upgrade Patches Guide
Note: 225813.1 - Installation, Patching & Upgrade Setup and Usage Guide
Note: 224816.1 - Installation, Patching & Upgrade Troubleshooting Guide
Note: 216550.1 - Oracle Applications Release 11i with Oracle9i Release 2 (9.2.0)
Note: 362203.1 - Oracle Applications Release 11i with Oracle 10g Release 2 (10.2.0)
Note: 423056.1 - Oracle Applications Release 11i with Oracle 10g Release 2 (10.2.0.2)
Note: 726982.1 - Oracle Applications Release 11i with Oracle 10g Release 2 (10.2.0.3)
Note: 452783.1 - Oracle Applications Release 11i with Oracle 11g Release 1 (11.1.0)
Note: 406652.1 - Upgrading Oracle Applications 11i DB to DB 10gR2 with Physical Standby in Place
Note: 316365.1 - Oracle Applications Release 11.5.10.2 Maintenance Pack Installation Instructions
Note: 418161.1 - Best Practices for Upgrading Oracle E-Business Suite

Printer

Note: 297522.1 - How to investigate printing issues and work towards its resolution ?
Note: 110406.1 - Check Printing Frequently Asked Questions
Note: 264118.1 - Pasta Pasta Printing Setup Test
Note: 200359.1 - Oracle Application Object Library Printer Setup Test
Note: 234606.1 - Oracle Application Object Library Printer Initialization String Setup Test
Note: 1014599.102 - Subject: How to Test Printer Initialization Strings in Unix

Performance

Note: 390137.1 - FAQ for Collections Performance
Note: 216205.1 - Database Initialization Parameters for Oracle Applications Release 11i
Note: 169935.1 - Troubleshooting Oracle Applications Performance Issues
Note: 171647.1 - Tracing Oracle Applications using Event 10046
Note: 153507.1 - Oracle Applications and StatsPack
Note: 356501.1 - How to Setup Pasta Quickly and Effectively
Note: 333504.1 - How To Print Concurrent Requests in PDF Format
Note: 356972.1 - 11i How to troubleshoot issues with printers

Others

Note: 189367.1 - Best Practices for Securing the E-Business Suite
Note: 403537.1 - Best Practices For Securing Oracle E-Business Suite Release 12
Note: 454616.1 - Export/Import Process for Oracle E-Business Suite Release 12 using 10gR2
Note: 394692.1 - Oracle Applications Documentation Resources, Release 12
Note: 370274.1 - New Features in Oracle Application 11i
Note: 130183.1 - How to Get Log Files from Various Programs for Oracle Applications
Note: 285267.1 - Oracle E-Business Suite 11i and Database FAQ
Note: 453137.1 - Oracle Workflow Best Practices Release 12 and Release 11i
Note: 398942.1 - FNDCPASS Utility New Feature ALLORACLE
Note: 187735.1 - Workflow FAQ - All Versions

Oracle Applications 11i/12 Online Documentation

http://www.oracle.com/technology/documentation/applications.html

Note: Above are only the few important notes, there are bunch of notes on many other issues and topics in the metalink. I would suggest one to refer the metalink for more note ids.

Leave your comments if you feel these Oracle Metalink Notes help you in solving your Application issues.

Regards,
Sabdar Syed,
http://sabdarsyed.blogspot.com/

Metalink is now My Oracle Support!

Yesterday, when I logged in to Oracle Metalink, I saw a new look of Metalink, and also Oracle Metalink Support has now been renamed to



As per My Oracle Support:


“Introducing My Oracle Support, the next generation MetaLink experience. My Oracle Support offers you secure, real-time access to Oracle experts on the complete Oracle software stack. It also provides groundbreaking personalized & proactive support capabilities that help reduce unplanned down time and improve system stability. Leverage the Internet for immediate access to 24/7 support and get the critical and timely information you need for running your usiness.”
A new look of My Oracle Support







Important Blog on new look of My Oracle Support.

Introducing... My Oracle Support!

Classic MetaLink vs. New MetaLink — What’s the Difference?

Regards,
Sabdar Syed,
http://sabdarsyed.blogspot.com/