12c Client: TNS-3505 or ORA-12154 Using TNSNAMES.ORA (Doc ID 2152990.1)

Last updated on JULY 06, 2021

Applies to:

Symptoms

A 12c client might fail to resolve a TNS connect string when there are multiple aliases separated by commas in a list.  This behavior would not have been present with previous versions of Oracle client. 

For example: 

MYDB,MYDB.us.oracle.com,MYDB.oracle.com =  <====Pre 12c clients would have been able to resolve any of these 3 TNS aliases without error.

    (DESCRIPTION =   (ADDRESS_LIST =   (ADDRESS = (PROTOCOL = TCP)(HOST = SCAN-HOST)(PORT = 1521)))   
        (CONNECT_DATA =   (SERVICE_NAME = MYDB.example.com)))

A 12c client may return the following error:  TNS-3505 or ORA-12154

ORA-12154: TNS:could not resolve the connect identifier specified
TNS-03505: TNS: Failed to resolve name

Changes

 This is a recent upgrade to a 12c client. 

Cause

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