Huge Wait On Database With "enq: CN - Race With Reg" Wait Event With The Use Of Query Change Notification

(Doc ID 2386606.1)

Last updated on APRIL 17, 2018

Applies to:

Oracle Database - Enterprise Edition - Version 11.2.0.4 and later
Information in this document applies to any platform.

Symptoms

Huge number of database sessions are waiting with wait event "enq: CN - race with reg". Querying the sys.reg$ shows huge number of registrations with LOCATION_NAME of the form "net8://...."

Changes

Client Result Cache feature is enabled at the database level.

Cause

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