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SYS Session loop with wait event 'RESMGR:CPU QUANTUM' while Create / Alter / Drop common users in multitenant environment with huge number of PDBs (Doc ID 2859078.1)

Last updated on APRIL 05, 2022

Applies to:

Oracle Cloud Infrastructure - Exadata Cloud Service - Version N/A to N/A [Release N/A]
Oracle Database Cloud Service - Version N/A to N/A [Release 1.0]
Gen 2 Exadata Cloud at Customer - Version N/A to N/A [Release All Releases]
Gen 1 Exadata Cloud at Customer (Oracle Exadata Database Cloud Machine) - Version N/A to N/A
Oracle Database - Enterprise Edition - Version 18.0.0.0 and later
Information in this document applies to any platform.

Symptoms

Information in this document applies to any platform where Oracle Database is version 12.2 and higher 

While creating a common user in a multitenant environment with a huge number of PDBs (more than 1000), might cause performance issues with a high no of sessions with wait event  'RESMGR:CPU QUANTUM'

F07781 ACTIVE resmgr:cpu quantum 1478,44091 170014 SYS oracle dbhost_11 oracle@dbhost_11 (PP17) sqlplus@dbhost_11 (TNS V1-V3) 1
F26859 ACTIVE resmgr:cpu quantum 3211,64898 175863 SYS oracle dbhost_11 oracle@dbhost_11 (PNJU) sqlplus@dbhost_11 (TNS V1-V3) 1
F02445 ACTIVE resmgr:cpu quantum 2166,30009 175861 SYS oracle dbhost_11 oracle@dbhost_11 (PNJV) sqlplus@dbhost_11 (TNS V1-V3) 1
F11851 ACTIVE resmgr:cpu quantum 5732,60975 175859 SYS oracle dbhost_11 oracle@dbhost_11 (PNJW) sqlplus@dbhost_11 (TNS V1-V3) 1
F16837 ACTIVE resmgr:cpu quantum 1567,55463 175857 SYS oracle dbhost_11 oracle@dbhost_11 (PNJX) sqlplus@dbhost_11 (TNS V1-V3) 1
F14982 ACTIVE resmgr:cpu quantum 4910,58819 175855 SYS oracle dbhost_11 oracle@dbhost_11 (PNJY) sqlplus@dbhost_11 (TNS V1-V3) 1
F16721 ACTIVE resmgr:cpu quantum 862,58989 175853 SYS oracle dbhost_11 oracle@dbhost_11 (PNJZ) sqlplus@dbhost_11 (TNS V1-V3) 1

Changes

To create common a user in a multitenant environment, with 1000s of PDBs, the user needs to be created in all the PDBs.
This is a resource-intensive operation and might cause performance issues if the environment is not sufficiently sized.

Cause

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In this Document
Symptoms
Changes
Cause
Solution
References

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