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External Procedures - Troubleshooting ORA-28575 Errors (Doc ID 70638.1)

Last updated on JULY 20, 2020

Applies to:

Oracle Database Cloud Schema Service - Version N/A and later
Gen 1 Exadata Cloud at Customer (Oracle Exadata Database Cloud Machine) - Version N/A and later
Oracle Cloud Infrastructure - Database Service - Version N/A and later
Oracle Database Exadata Express Cloud Service - Version N/A and later
Oracle Database Backup Service - Version N/A and later
Information in this document applies to any platform.
*** Checked for relevance on 20-Jul-2020 ***


This article provides brief overview of the Oracle external procedure architecture and provides a number of suggestions for troubleshooting the "ORA-28575 unable to open RPC connection to external procedure agent" error. Although the emphasis of this bulletin is on the UNIX environment, many of the concepts also apply to windows environments as well.

This article does not address all aspects of the external procedures. It just provides enough background information to troubleshooting the ORA-28575 error.


A list of the essential components for executing an external procedure is included below, along with a brief description of the role of each component.



    1. The AGENT or AGENT IN clause with the PL/SQL library or PL/SQL call specification.
    2. When Multi-Threaded extproc (MTA) is configured.

Otherwise default configuration is recommended.

Extproc Agent:

Shared or Dynamic link library (In case of Windows):

External procedure call specification:


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