My Oracle Support Banner

Datapump Import May Slow Down Due To "RAC: constraint DDL lock" Waits (Doc ID 2056924.1)

Last updated on FEBRUARY 14, 2019

Applies to:

Oracle Database - Enterprise Edition - Version to [Release 11.2 to 12.1]
Oracle Database Cloud Schema Service - Version N/A and later
Oracle Database Exadata Cloud Machine - Version N/A and later
Oracle Database Exadata Express Cloud Service - Version N/A and later
Oracle Cloud Infrastructure - Database Service - Version N/A and later
Information in this document applies to any platform.


Customer may see performance issues with the datapump import, when importing schemas with large database schemes with several database constraints.

Trace files indicate that the worker processes spent long time on "RAC: constraint DDL lock" wait.

Chain 7:
    Oracle session identified by:
                instance: 2 (<HOSTNAME>)
                   os id: 60170
              process id: 181, oracle@<HOSTNAME> (DW00)
              session id: 433
        session serial #: 59775
    is waiting for 'RAC: constraint DDL lock' with wait info:
                      p1: 'maximum attempts'=0x78
                      p2: 'attempt count'=0x1
            time in wait: 0.212016 sec
           timeout after: 0.787984 sec
                 wait id: 1331503
                blocking: 0 sessions
             current sql: CREATE TABLE "<USER>"."<TABLE_NAME>" .......
             short stack:



To view full details, sign in with your My Oracle Support account.

Don't have a My Oracle Support account? Click to get started!

In this Document

My Oracle Support provides customers with access to over a million knowledge articles and a vibrant support community of peers and Oracle experts.