Shutdown Immediate Slow in a 12C PDB Environment (Doc ID 1984138.1)

Last updated on MAY 31, 2016

Applies to:

Oracle Database - Enterprise Edition - Version 12.1.0.2 and later
Information in this document applies to any platform.

Symptoms

 'ALTER PLUGGABLE DATABASE ALL CLOSE' is slow.

The alert log of the CDB shows the below messages :-

Fri Jan 23 10:51:39 2015
alter pluggable database all close immediate
Fri Jan 23 10:51:39 2015
Fri Jan 23 10:51:41 2015
ALTER SYSTEM: Flushing buffer cache inst=1 container=9 local
Pluggable database MYPDB1_PDB closed
Fri Jan 23 10:51:42 2015
ALTER SYSTEM: Flushing buffer cache inst=1 container=4 local
Pluggable database MYPDB2_PDB closed
Fri Jan 23 10:51:43 2015
ALTER SYSTEM: Flushing buffer cache inst=1 container=13 local
Pluggable database MYPDB3_PDB closed
Fri Jan 23 10:51:44 2015
ALTER SYSTEM: Flushing buffer cache inst=1 container=3 local
Pluggable database MYPDB4_PDB closed
Fri Jan 23 10:51:44 2015
ALTER SYSTEM: Flushing buffer cache inst=1 container=8 local
Pluggable database MYPDB5_PDB closed
Fri Jan 23 10:51:46 2015
ALTER SYSTEM: Flushing buffer cache inst=1 container=10 local
Fri Jan 23 10:51:47 2015
ALTER SYSTEM: Flushing buffer cache inst=1 container=15 local
Fri Jan 23 10:51:47 2015
ALTER SYSTEM: Flushing buffer cache inst=1 container=5 local
Fri Jan 23 10:51:48 2015
ALTER SYSTEM: Flushing buffer cache inst=1 container=6 local
Fri Jan 23 10:51:48 2015
Pluggable database MYPDB6_PDB closed
Fri Jan 23 10:51:48 2015
Pluggable database MYPDB7_PDB closed
Fri Jan 23 10:51:48 2015

 

From the above messages we can see, the CDB closes the PDBs one after another, which is a serial operation.
And for each PDB, the DB writes try to scan through the buffer cache and flush the parts which belong to that PDB.

Cause

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