Error
Error Code: ORA-27123

Oracle Error ORA-27123: Shared Memory Issue

📦 Oracle Database
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Description

The ORA-27123 error indicates that the Oracle database server is unable to attach to a shared memory segment. This typically occurs during database startup or when a process attempts to access shared memory required for database operations.
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Error Message

ORA-27123: unable to attach to shared memory segment
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Known Causes

4 known causes
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Insufficient Permissions
The Oracle user lacks the necessary permissions to access the shared memory segment. This can happen if the file system permissions are incorrect or if the Oracle user is not part of the correct group.
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Shared Memory Exhaustion
The system has exhausted available shared memory resources, preventing the Oracle process from attaching to the required segment. Other applications or Oracle instances may be consuming excessive shared memory.
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Incorrect SHMMAX Setting
The `SHMMAX` kernel parameter, which defines the maximum size of a shared memory segment, might be set too low for the Oracle instance's requirements. This limits the size of shared memory segments that can be created.
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Resource Conflicts
Another process might be holding a lock or interfering with the shared memory segment, preventing Oracle from attaching to it. This could be due to a rogue process or a misconfigured application.
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Solutions

Coming Soon

Detailed step-by-step solutions for this error are being prepared. In the meantime, try these general troubleshooting tips:

General Troubleshooting Tips

  • Check the error message carefully for specific details
  • Review recent changes that might have caused the error
  • Search for the exact error code in the official documentation
  • Check log files for additional context
  • Try restarting the application or service

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