Connect Via SCAN Intermittently Fails With ORA-12516: TNS:listener Could Not Find Available Handler With Matching Protocol Stack (Doc ID 1638175.1)

Last updated on OCTOBER 13, 2016

Applies to:

Oracle Database - Enterprise Edition - Version 11.2.0.3 and later
Information in this document applies to any platform.

Symptoms

o multinode (3+) RAC  cluster
o application using SCAN and a dedicated service (here serv1) to connect to the database
o service is configured to run on instances 1 & 2 (preferred)
o intermittently connect attempts fail with error
  ORA-12516: TNS:listener could not find available handler with matching protocol Stack

Cause

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