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BUG – High “row Cache Mutex” Waits – Oracle 19C
Category: Database Author: Andre Luiz Dutra Ontalba (Board Member) Date: 4 years ago Comments: 0

BUG - High "row Cache Mutex" Waits - Oracle 19c

Today, during an analysis of a performance problem in Oracle 19c, I found an event strange that I had not seen before.
 
I started looking at the event “ROW CACHE MUTEX” with a large number of events in 1 hour of process execution.

 

 

We can see above in 1 hour of processing we had 2,184,882 events with consumption of 51.92% of DB time. 
 
 I can found this bug in Oracle Support
 
Bug 31933451 – High “row Cache Mutex” Waits (Doc ID 31933451.8)
 
Symptoms:
  • Hang (Involving Shared Resource)
  • Internal Error May Occur (ORA-600)
  • Waits for “Row Cache Mutex”
 
Description
Too many row cache objects are being copied or ‘cloned’.  This fix ensures that only the ‘hot’ objects are cloned, not every object on the hash chain.
 
This problem affects all versions 19.x. 
 
There is no workaround for this problem.
 
In version 21.1 is fixed the problem.
 
There is already a specific one-off patch for this released in December.
After the patch was applied, an AWR collection was performed again and we could see that it resolved with an impressive result.
We had a 95.72% reduction in the “ROW CACHE MUTEX” event contention.
 
I hope I helped with this article
 
Stay tuned, following on twitter @aontalba and on Linkedin
 
Andre Ontalba

 

Disclaimer: “The postings on this site are my own and don’t necessarily represent may actual employer positions, strategies or opinions. The information here was edited  to be useful for general purpose, specific data and identifications was removed to allow reach generic audience and to be useful.”


New feature – Bring Your Own IP
Category: Cloud Author: Andre Luiz Dutra Ontalba (Board Member) Date: 4 years ago Comments: 0

New feature - Bring Your Own IP

Now Oracle Cloud Infrastructure allows you to Bring Your Own IP (BYOIP) address space to use with resources in Oracle Cloud Infrastructure. BYOIP lets you manage your IPv4 CIDR blocks to align with your existing deployment policies, security, management and achieve:

 

  • Solution continuity and hardcoded dependencies
  • IP pool management
  • IP reputation
 
The Oracle performs a validation process on imported CIDR blocks, and after validation you are notified that the CIDR block is available for advertisement.

 

Limits and Quotas

 

  • A CIDR block that is /24 or smaller is required for addresses to be advertised to the Internet.
  • You can’t bring more than 10 IPv4 address ranges to your OCI account.
  • You can create up to 10 pools.
  • BYOIP is not available to Oracle Cloud Infrastructure Free Tier or Pay As You Go services.
  • Your addresses can only be imported to a specific Oracle region.
  • You can use BYOIP with a CIDR block that is a minimum of /24 and a maximum of /8.
  • You can’t bring the same address range to more than one compartment at a time.
 

Requirements and Preparation

You must have ownership of the public IPv4 CIDR block you want to import into Oracle Cloud Infrastructure, and the ownership must be registered with a supported Regional Internet Registry (RIR). The Oracle validates ownership of your addresses. Only the following registries are supported, and the addresses must have a specified type or status:

 

 

The addresses in the IP address range must have a clear history. Oracle can investigate the reputation of the IP address range and may reject a range of IP addresses that contains an IP address associated with malicious behavior.

 

 

 

The steps required for BYOIP on Oracle Cloud Infrastructure require significant time, so plan ahead to perform such an import.
 
I hope this helps you!!!
Andre Luiz Dutra Ontalba

 

 

Disclaimer: “The postings on this site are my own and don’t necessarily represent may actual employer positions, strategies or opinions. The information here was edited  to be useful for general purpose, specific data and identifications was removed to allow reach generic audience and to be useful.”


Oracle Groundbreakers EMEA – Virtual Tour 2020 (LuxOUG)
Category: Database Author: Andre Luiz Dutra Ontalba (Board Member) Date: 4 years ago Comments: 0

Oracle Groundbreakers EMEA - Virtual Tour 2020 (LuxOUG)

This year is different, in all it’s aspects. For the OGB EMEA Virtual Tour 2020, this year is about diversity, is about #BackToBasics.
 
For two weeks, speakers from all over the world will come to our houses bringing one of the most valuable gift: their knowledge. Everyone will learn something, regardless how many years of experience we have or how “fresh and new” we are.
 
LuxOUG will be part of this great event. See the agenda and register for all events you wish to participate !!!

 

Link to event registration:  http://ogbemea.com/02-oct-2020/
 
See you at the event !!
 

opatch fails with Error: ‘Archive Action: Source file “$ORACLE_HOME/.patch_storage/…” does not exist.’
Category: Database,Engineer System Author: Andre Luiz Dutra Ontalba (Board Member) Date: 4 years ago Comments: 0

opatch fails with Error: 'Archive Action: Source file "$ORACLE_HOME/.patch_storage/..." does not exist.'

 
Another quick article about a problem I had yesterday during an update patch in ODA. I found an error during patch in the Oracle Binary.

 

[Sep 14, 2020 2:40:58 PM] [INFO] add CopyAction for olsrelod.sql
[Sep 14, 2020 2:40:58 PM] [INFO] OPatchSessionHelper::sortOnOverlay() Given list - 25897615 25034396 26477255 20370037 21688501 18430870 27435440 24425998
[Sep 14, 2020 2:40:58 PM] [INFO] size of PatchObject list: 8
[Sep 14, 2020 2:40:59 PM] [INFO] Patch 24425998:
Achive Action: Directory "/u01/app/oracle/product/12.1.0.2/dbhome_3/.patch_storage/24425998_Sep_28_2016_12_31_24" does not exists or is not readable.
'oracle.rdbms, 12.1.0.2.0': Cannot update file '/u01/app/oracle/product/12.1.0.2/dbhome_3/lib/libserver12.a' with '/ksfd.o'
[Sep 14, 2020 2:40:59 PM] [INFO] Prerequisite check "CheckRollbackable" on auto-rollback patches failed.
The details are:

Patch 24425998:
Achive Action: Directory "/u01/app/oracle/product/12.1.0.2/dbhome_3/.patch_storage/24425998_Sep_28_2016_12_31_24" does not exists or is not readable.
'oracle.rdbms, 12.1.0.2.0': Cannot update file '/u01/app/oracle/product/12.1.0.2/dbhome_3/lib/libserver12.a' with '/ksfd.o'
[Sep 14, 2020 2:40:59 PM] [SEVERE] OUI-67073:UtilSession failed: Prerequisite check "CheckRollbackable" on auto-rollback patches failed.
[Sep 14, 2020 2:40:59 PM] [INFO] --------------------------------------------------------------------------------
[Sep 14, 2020 2:40:59 PM] [INFO] The following warnings have occurred during OPatch execution:
[Sep 14, 2020 2:40:59 PM] [INFO] 1) OUI-67303:
Patches [ 25897615 25034396 26477255 20370037 21688501 18430870 27435440 24425998 ] will be rolled back.
[Sep 14, 2020 2:40:59 PM] [INFO] 2) OUI-67303:
Patches [ 25897615 25034396 26477255 20370037 21688501 18430870 27435440 24425998 ] will be rolled back.
[Sep 14, 2020 2:40:59 PM] [INFO] --------------------------------------------------------------------------------
[Sep 14, 2020 2:40:59 PM] [INFO] Finishing UtilSession at Mon Sep 14 14:40:59 CEST 2020
[Sep 14, 2020 2:40:59 PM] [INFO] Log file location: /u01/app/oracle/product/12.1.0.2/dbhome_3/cfgtoollogs/opatchauto/core/opatch/opatch2020-09-14_14-39-20PM_1.log

 

According to the document: opatch fails with Error: ‘Archive Action: Source file “$ ORACLE_HOME / .patch_storage / …” does not exist.’ or ‘Achive Action: Directory “$ ORACLE_HOME / .patch_storage / …” does not exist or is not readable’. (Doc ID 1244414.1)
The reason for this is:
Files needed to rollback existing subset patch (es) are missing from $ORACLE_HOME/.patch_storage.

BACKGROUND
==============
When an Oracle software patch is installed, the first step is to place an unmodified copy of each affected $ORACLE_HOME file into a directory under the “$ORACLE_HOME/.patch_storage”.  These file copies will be used if the software patch is ever manually, or automatically rolled back.

 

Well after I saw this error, I was sure that nothing had been removed before the patch.
 
The only supported solutions:

 

  1. The missing directories and files can be restored from a backup of the ORACLE_HOME.
  2.  
  3. If no backups exist then re-install the $ORACLE_HOME.
  4.  
  5. Clone from another ORACLE_HOME of a like installation.

 

 

In my case I always have the backup of the following directories $ORACLE_HOME/inventory/oneoffs and    $ORACLE_HOME/.patch_storage.
 
I found the patch folder /.patch_storage/24425998_Sep_28_2016_12_31_24 that was needed to perform the rollback and after that the patch was applied successfully.
 
2020-09-15 07:47:04 Patch 29972716 is successfully already applied on the Home: /u01/app/oracle/product/12.1.0.2/db_home3
2020-09-15 07:47:04 SUCCESS: Successfully applied the patch on the Home : /u01/app/oracle/product/12.1.0.2/db_home4, /u01/app/oracle/product/12.1.0.2/db_home1, /u01/app/oracle/product/12.1.0.2/db_home3.

 

I hope this helps you!!!
 
Stay tuned, following on twitter @aontalba and on Linkedin

 

Andre Luiz Dutra Ontalba

 

Disclaimer: “The postings on this site are my own and don’t necessarily represent may actual employer positions, strategies or opinions. The information here was edited  to be useful for general purpose, specific data and identifications was removed to allow reach generic audience and to be useful.”


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